Food comes first: methodologies for the National Nutrition Survey of New Zealand

Tags: New Zealand, National Nutrition Survey, National Nutrition, University of Otago, National Nutrition Survey of New Zealand, Methodologies, food intake, New Zealanders, New Zealand Health, Ministry of Health, participant, Nutrition, measurements, food frequency questionnaire, FOOD SECURITY, SHOW CARD, interviewer, New Zealand Health Survey, FOOD SECURITY SHOW CARD, Dr Murray Skeaff Department of Human Nutrition, Dr Boyd Swinburn National Heart Foundation., Parnell Dr Caroline Horwath Dr Elaine Ferguson, Mark Clements Advisor, survey methodologies, Statistics New Zealand, Public Health Group, Public Health Commission
Content: PUBLIC HEALTH REPORT NUMBER 2 FFOOOODD CCOOMMEESS FFIIRRSSTT:: MMEETTHHOODDOOLLOOGGIIEESS FFOORR TTHHEE NNAATTIIOONNAALL NNUUTTRRIITTIIOONN SSUURRVVEEYY OOFF NNEEWW ZZEEAALLAANNDD Robert Quigley BSc, BCApSc, Dip Diet, NZRD Coordinator of the National Nutrition Survey Carolyn Watts BCApSc, NZRD Advisor (Nutrition) Published with the permission of the Director-General of Health Published in October 1997 by public health group ministry of health Wellington, New Zealand ©1997 Ministry of Health, PO Box 5013, Wellington ISBN 0-478-20862-6 (booklet) ISBN 0-478-20863-4 (internet) Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 39
FOREWORD This report is the second in the new report series published by the Public Health Group of the Ministry of Health. This series carries on from the five bulletins that were produced by the former Public Health Commission. The reports fall into two groups. Reports in the first group provide a more detailed analysis of the epidemiology and scientific literature related to a particular public health issue, which is used to inform policy advice. Reports in the second group consider methodological issues, which are either used to strengthen the Ministry's ability to monitor and report on the state of the public health, and/or support the implementation of policy. This report on the National Nutrition Survey methodologies falls into this second group. The purpose is to inform interested parties in New Zealand and internationally about the objectives of the National Nutrition Survey and to provide a description of the methodologies that were used in data collection. Up to date knowledge about the food and nutrient intake and nutritional status of New Zealanders is critical to achieving the Ministry of Health's goal of healthy New Zealanders. The National Nutrition Survey represents a major investment in nutrition information by the Ministry of Health. We would be pleased to receive comments or suggestions on this report and applications for use of the methodologies. Readers are invited to write to the Public Health Group, Ministry of Health, PO Box 5013, Wellington. Karen O Poutasi (Dr) Director-General of Health October 1997 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand i
CONTENTS
FOREWORD
Page __________________________________________________________ i
INTRODUCTION __________________________________________________________ 1
Objectives of the National Nutrition Survey __________________________________ 2
BACKGROUND __________________________________________________________ 3 Other Surveys _________________________________________________________ 3 National Diet Survey 1977 __________________________________________ 3 The Life in New Zealand Survey 1989-1990 ____________________________ 3 The New Zealand Health Survey _____________________________________ 4 Linking the New Zealand Health Survey and the National Nutrition Survey _____________________________________ 4 Supporting Groups _____________________________________________________ 4 The Ministry for the Environment ____________________________________ 5 Mдori and Pacific Issues _________________________________________________ 5 Computer-assisted data entry _____________________________________________ 6
THE TENDERING PROCESS FOR THE NATIONAL NUTRITION SURVEY _________ 7
SAMPLE FRAME __________________________________________________________ 8 Selecting the population sampling units _____________________________________ 9 Selecting households within population sampling units _________________________ 9 Selecting a single respondent within a household _____________________________ 9 Sample size __________________________________________________________ 10 Sample groupings for analyses ____________________________________________ 10 Timing of sampling _____________________________________________________ 10 Household contact ______________________________________________________ 11 Non-respondent information ______________________________________________ 11
ii Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
METHODOLOGIES _________________________________________________________ 12 Pretesting the National Nutrition Survey Methodologies ________________________ 12 The order of survey methodologies _________________________________________ 14 Interviewers __________________________________________________________ 14 Multiple-pass 24-hour dietary recall methodology _____________________________ 15 Carrying out the multiple-pass 24-HDR _______________________________ 17 Repeat sample ____________________________________________________ 18 Analysis of data __________________________________________________ 19 Dietary supplements ____________________________________________________ 20 `Your usual food intake' questionnaire ______________________________________ 21 Quantitative versus qualitative food frequency questionnaire _______________ 21 Objectives of the food frequency questionnaire __________________________ 22 Format __________________________________________________________ 22 Pretesting _______________________________________________________ 22 Repeatability study ________________________________________________ 22 Completing the questionnaire ________________________________________ 23 Barriers to dietary change ________________________________________________ 25 Food security indicators _________________________________________________ 26 Environmental chemicals ________________________________________________ 27 Blood pressure _________________________________________________________ 28 Anthropometric measurements ____________________________________________ 29 Height __________________________________________________________ 29 Weight __________________________________________________________ 30 Circumference measurements _______________________________________ 30 Elbow breadth ____________________________________________________ 30 Skinfolds ________________________________________________________ 31 Blood samples _________________________________________________________ 31 Storage of blood samples ___________________________________________ 32 INTERVIEW TIMES _________________________________________________________ 34 ETHICAL ISSUES __________________________________________________________ 35 Informed Consent _______________________________________________________ 35 Feedback to participants _________________________________________________ 35 PROMOTIONAL MATERIALS ________________________________________________ 36 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand iii
ACKNOWLEDGMENTS _____________________________________________________ 37 Non-Ministry members of the National Nutrition Survey Technical Advisory Committee ____________________________________________________ 37 Ministry of Health members of the National Nutrition Survey Technical Advisory Committee ____________________________________________________ 38 Independent experts involved in the selection process __________________________ 39 The University of Otago _________________________________________________ 39 Personnel ________________________________________________________ 39 Principal investigators _____________________________________________ 40 Consultants ______________________________________________________ 40
APPENDICES ___________________________________________________________ 41 Appendix 1: Food/Nutrient-matching flow chart _____________________________ 41 Appendix 2: Dietary supplements questions _________________________________ 42 Appendix 3: `Your usual food intake' questionnaire ___________________________ 48 Appendix 4: Barriers to dietary change questions _____________________________ 64 Appendix 5: Food security questions _______________________________________ 76 Appendix 6: Environmental chemicals questions _____________________________ 80 Appendix 7: Consent forms ______________________________________________ 82 Appendix 8: Participant feedback letters ____________________________________ 85 Appendix 9: Participant information pamphlet _______________________________ 89 Appendix 10: health professionals' information pamphlet ______________________ 91 Appendix 11: University of Otago change of address card ______________________ 93 Appendix 12: University of Otago calling card _______________________________ 94
GLOSSARY
___________________________________________________________ 95
REFERENCES ___________________________________________________________ 102
iv Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
INTRODUCTION Nutrition is a key factor in the continued health and wellbeing of New Zealanders. At all stages of life, people require appropriate food and nutrient intakes to maintain good health and to guard against developing illness and disease. Food is an important part of the New Zealand lifestyle, not only in terms of health, but also in terms of social, cultural and spiritual significance. Knowledge about the food and nutrient intake and nutritional status of New Zealanders is critical to the work of the Ministry of Health. The need for improved knowledge was the driving force behind the development of the National Nutrition Survey in 1996 and 1997. The most recent information about New Zealanders' eating habits was collected in 1989­1990 (Russell and Wilson 1991). It is important to collect information at regular intervals so that policy and strategy can be updated and reflect the current situation for nutrition in New Zealand. The Ministry of Health intends to repeat the National Nutrition Survey on a regular basis, either five or ten yearly, so that a time series can be established for ongoing monitoring of nutrition. The objectives of the National Nutrition Survey highlight the reasons why it is so important to collect information on the nutritional status of New Zealanders. The objectives also outline the many ways in which the Ministry of Health and others will use the information. Health promotion through nutrition messages may help reduce ischaemic heart disease, cancer and stroke, which are the three leading causes of death and illness for New Zealanders. The Ministry of Health contracted the University of Otago to develop the National Nutrition Survey methodologies, undertake the fieldwork and produce summary results. The National Nutrition Survey was a voluntary cross-sectional population survey. The sample frame for the National Nutrition Survey was dependent on the sample frame for the New Zealand Health Survey. Approximately 5000 adults were interviewed in their homes between December 1996 and December 1997 for the National Nutrition Survey. Significant over-sampling of Mдori and Pacific people occurred to improve the data collected for these groups. The methodologies in the National Nutrition Survey have been designed as a computerassisted data entry system. The methodologies are: multiple pass 24-hour diet recall (24-HDR); dietary supplements; qualitative food frequency questionnaire and key food habits (optically scannable); barriers to dietary change; food security; environmental chemicals; blood pressure; selected anthropometric measurements; and blood samples. Data will be released publicly in January 1999. This bulletin outlines the objectives of the National Nutrition Survey, its background, and the methodologies that were used in data collection. The survey represents a major investment in nutrition information by the Ministry of Health. Publication of this material will be useful to others in New Zealand and internationally who may be undertaking similar research initiatives. The Ministry of Health will also be encouraging other researchers to use the results when they are released, so that the information can be of maximum benefit to the health of New Zealanders. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 1
OBJECTIVES OF THE NATIONAL NUTRITION SURVEY The objectives for the survey were based on those in the National Plan of Action for Nutrition (PHC 1995), which emphasised the need for a National Nutrition Survey as a means of gaining current information on the nutritional status of New Zealanders. The Ministry had the following objectives for the National Nutrition Survey. · To ensure participation of Mдori at all levels through appropriate consultation, resource allocation and the development of culturally-appropriate practices for collection and dissemination of data. · To provide data on nutrient and food intakes that are suitable for risk assessment required for setting and reviewing national and international regulatory food policies (such as fortification and contaminant monitoring). · To assist in the development of food policy and regulations related to food composition and safety, and assist in the provision of information related to food production, manufacture and sales. · To monitor food and nutrient intakes against the Food and Nutrition Guidelines for New Zealand (Report of the Nutrition Taskforce 1991), compare nutrient intakes with the recommended dietary intakes (RDIs) and assist in future revision of RDIs. · To provide baseline data on the nutritional status and food security of the population for comparisons with future surveys. · To assess changes in dietary habits over time and provide a basis for comparisons with future regular surveys. · To assist with the ongoing development of, and monitor the impact of, New Zealand's nutrition policy, monitor health goals and targets for nutrition and diet-related diseases and assist in the revision of future health goals and targets. · To provide information on the inter-relationship of health, social, economic and nutrition variables in selected population subgroups for policy development, including health promotion. · To provide a basis for nutrition education and other strategies to improve nutrition, and to provide a means of measurement for existing nutrition programmes. · To facilitate the development of nutritional status and dietary intake indicators which could be used for more regular surveillance. · To provide information on the levels of chlorinated organic chemicals (dioxins, poly chlorinated biphenyls (PCBs) and pesticides) in New Zealanders, which can be used for the development of policy and national environmental standards. · To provide this much-needed information to external users such as dietitians, nutritionists, the food industry and Mдori health providers. 2 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
BACKGROUND The National Nutrition Survey is the third national survey carried out in New Zealand that has gathered information on the nutritional status of New Zealanders. The planning and operation of the National Nutrition Survey has received interest and support from a range of national and other government organisations. The interactions between the New Zealand Health Survey and National Nutrition Survey have been important considerations throughout the entire survey. OTHER SURVEYS NATIONAL DIET SURVEY 1977 The National Diet Survey, funded by the National Heart Foundation in 1977, was the first nationwide survey of New Zealanders' dietary habits (Birkbeck 1983). The survey had a range of methodologies that focused on the possible factors that may affect coronary heart disease. Dietary intake was estimated using 24-HDR, with a supplementary questionnaire covering dietary supplements, use of iodised salt and smoking habits. Anthropometric measures were: height; sitting height; weight; mid-upper arm circumference; and triceps and subscapular skinfold thickness. THE LIFE IN NEW ZEALAND SURVEY 1989-1990 The Life in New Zealand (LINZ®) survey conducted in 1989­1990 by the University of Otago for the Hillary Commission for Recreation and Sport with supplementary funding from other organisations and the Department of Health, was the most recent national survey to include measures of nutritional status and dietary intake. The LINZ® survey focused on physical activity and leisure patterns, and included dietary intake measurement by 24-HDR on a subsample of 1,702 people. Two qualitative food frequency questionnaires were completed by 4,683 people. Physical measures included weight; height; six skinfold thicknesses; waist, hip, mid-upper arm and calf circumference; elbow and knee width; and blood pressure. A blood sample was taken and blood lipids measured. The LINZ® survey data are the most recent national data available for dietary intake. The survey data may not be representative of Mдori as the numbers of Mдori who participated in the survey were small. The 1996­1997 National Nutrition Survey data will be compared with the LINZ® survey data to establish trends in dietary intake where this is appropriate. There are significant differences in the 24-HDR methodologies used between the two surveys and the New Zealand Food Composition Database (NZFCD) has changed significantly. Direct comparisons for all intake data will not be possible. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 3
THE NEW ZEALAND HEALTH SURVEY At the same time as the National Nutrition Survey was being developed, the Ministry of Health and the four regional health authorities were also planning the New Zealand Health Survey. This was also a nationwide survey and followed the 1992­1993 Household Health Survey. The aims of the 1996 ­1997 New Zealand Health Survey were to provide information on the health status, use of health services, and health risk factors of New Zealanders. The New Zealand Health Survey was carried out in the participants' homes, with questionnaires taking approximately 30 minutes to complete. The questionnaires were mostly interviewer-administered but a short self-completed questionnaire was also used. Parents and caregivers were also asked a small number of questions about children in their care. The New Zealand Health Survey was developed by the Ministry of Health and the four regional health authorities. Linking the New Zealand Health Survey and the National Nutrition Survey It became obvious early in the development of the National Nutrition Survey that the Ministry would need to link the two surveys together so that the people selected to participate in the New Zealand Health Survey would also be asked to participate in the National Nutrition Survey. This would: · decrease the survey burden on the total New Zealand population by using only one sample frame · reduce the cost for the National Nutrition Survey · enable the collection of one set of socio-Demographic data for use in both surveys · create a linked data set of health and nutrition information. Statistics New Zealand was contracted to develop the New Zealand Health Survey design and sampling methodology, assist with the final development of the questionnaire, pretest the health survey, carry out fieldwork for the health survey, process the health survey results and prepare a clean data set. Interviewing for the New Zealand Health Survey started on 14 October 1996. The decision by the Ministry to link the two surveys placed tight timeframes around the University of Otago's contracts to develop the National Nutrition Survey methodologies and prepare for the fieldwork. The University of Otago entered into a separate contract with Statistics New Zealand for the transfer of personal identification data between the two organisations. SUPPORTING GROUPS The Ministry of Health has had significant support from other governments. In particular, the Agriculture Research Service of the United States Department of Agriculture and the Australian Commonwealth Department of Health and Family Services have had considerable input into New Zealand's National Nutrition Survey methodologies, further strengthening inter-governmental ties in public health. The methodologies used in the New Zealand National Nutrition Survey are similar to those used by the American and Australian governments, which may allow international comparisons to be made. 4 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
Individuals from non-governmental agencies, nutrition experts and other individuals have had significant involvement in the planning and development of the survey, especially those involved in the National Nutrition Survey Technical Advisory Committee (NNSTAC). Recognising that a diverse range of skills were required to plan and develop a successful National Nutrition Survey, the Ministry set up the NNSTAC to provide technical and cultural advice on all aspects of the survey. The committee met at regular intervals throughout the planning and development of the methodologies, holding its first meeting in August 1995. The members are listed in the acknowledgments. THE MINISTRY FOR THE ENVIRONMENT There is considerable interest within government agencies to conduct inter-agency work where possible. The Ministry of Health carried out an extensive campaign to inform other government agencies about the New Zealand Health Survey and National Nutrition Survey. From this campaign, the Ministry for the Environment expressed an interest in the blood samples being collected in the National Nutrition Survey. The Ministry for the Environment was conducting an Organochlorines Programme, which had a primary aim of developing national environmental standards and guidelines for organochlorine substances. The application of these standards and guidelines will safeguard human health by regulating any further ongoing emissions of organochlorines into the environment. Collection of blood samples will allow the determination of the baseline levels of persistent organochlorine chemicals in the general New Zealand population. These data will be one facet of the larger Organochlorines Programme. Otago University and the Ministry for the Environment had a separate contract to cover the collection and processing costs for the organochlorine blood sample and the set of interviewer-administered questions which they required. MAORI AND PACIFIC ISSUES Mдori and Pacific advisors have been involved in the National Nutrition Survey at every stage of development as part of the NNSTAC, and have been working with the University of Otago on the survey. This ensured that the methodologies would be designed in a culturally-appropriate manner, that the information collected would be useful for Mдori and Pacific people and that data analyses occurred in an appropriate manner. This is further reflected by the Ministry of Health's decision to over-sample Mдori and Pacific participants to improve the quality of data collected for Mдori and Pacific people. Te Rцpu Rangahau Hauora a Eru Pцmare (the Eru Pцmare Mдori Health Research Centre) was involved in the National Nutrition Survey providing Mдori input into all decisions. A senior lecturer from the University of Auckland provided Pacific input into all decisions. Several other Mдori and Pacific consultants have also assisted the University of Otago team, to ensure that the National Nutrition Survey best met the needs of New Zealand's diverse population. Te Rцpu Rangahau Hauora a Eru Pцmare also provided a letter for the interviewers of the New Zealand Health Survey to leave with Mдori households. The letter discussed why it was important for Mдori to participate in the National Nutrition Survey, explained the purpose of the survey and encouraged Mдori to participate. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 5
Ten Mдori field team support officers were employed by the University of Otago to provide assistance to the interview staff. Their main roles were: · to promote the survey to Mдori health workers and their local community · to be available to answer questions on the survey from Mдori participants and Mдori health workers. COMPUTER-ASSISTED DATA ENTRY The objectives of the National Nutrition Survey were very clearly set out at the start of the survey development. The University of Otago had the challenge to deliver those objectives within tight timeframes and budget. To achieve them, the University developed a new computer-assisted data capture system for all responses in the National Nutrition Survey, except the food frequency questionnaire and key food habits questions. There were many advantages to using this technology compared with paper and pencil data collection, including the following. · Paper and pencil recording followed by coding and checking of coding is triple handling of information. Direct entry of data saves coding time and therefore money and eliminates the errors associated with coding the data at a later date. · The controlled questioning process reduces interviewer variability. · Computer-assisted questioning always `skips' to the next appropriate question in the questionnaire depending on the answer. This guides the interviewer through the interview. · Error checks have been built into the software at the data entry stage to question unlikely responses. For example, a person's height of 280 cm would be queried directly after data entry. The interviewer can ratify or correct the value. · Computer-assisted entry has allowed all the interview questions to be directly stored on the computer, negating the need for heavy and cumbersome manuals. · Computer-assisted data entry has allowed time saving in the multiple-pass 24-HDR, in particular using the bar code scanner to identify products consumed. · Within the multiple-pass 24-HDR, computer-assisted entry ensures that all `probe questions' relevant to the foods consumed by a participant are asked by the interviewer. · Every question requires an answer before moving on to the next. · Built-in time lags remind the interviewer that they must take a 60-second pause between the blood pressure readings. · The difference in the first and second readings of anthropometric data are calculated immediately and the interviewer may be instructed to perform a third reading if the difference between the first two measurements is too large. · Completed interviews can be returned to the University of Otago by copying to a single diskette. 6 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
THE TENDERING PROCESS FOR THE NATIONAL NUTRITION SURVEY Late in 1995, the Ministry of Health entered into the process of tendering out the National Nutrition Survey. For contracting purposes, the National Nutrition Survey was broken into three distinct contracts. Firstly, the development of the qualitative food frequency, key food habits and barriers to dietary change questionnaires was tendered. This served a dual purpose: to begin development on a methodology knowing that the overall timeframes were very tight; and also to alert the Ministry to the potential providers for the full survey. Potential providers for the full survey were requested to submit a proposal to develop the remaining methodologies to be used in the National Nutrition Survey. Both these contracts were won by the University of Otago. A third contract was then negotiated with the University of Otago to undertake the fieldwork for the National Nutrition Survey and also undertake preliminary analyses of the data. The total cost for the three contracts was $3.066 million (excluding Goods and Services Tax). The Ministry of Health staff and independent experts who participated in this process are listed in the acknowledgments. The University of Otago team are also listed in the acknowledgments. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 7
SAMPLE FRAME A consequence of linking the two concurrent surveys was that the sample frame for the National Nutrition Survey was dependent on the sample frame for the New Zealand Health Survey. The New Zealand Health Survey and National Nutrition Survey sample frame was selected by Statistics New Zealand after consideration of both surveys' requirements. The target population for the surveys was the civilian usually-resident population 15 years of age and over in New Zealand. A number of standard exclusions from the population were made. These were: · people living in non-private dwellings · long-term residents of rest homes · people in hospitals and psychiatric institutions · inmates of penal institutions · members of the permanent armed forces · overseas diplomats · overseas visitors who expect to be resident in New Zealand for less than 12 months · people living on offshore islands (except Waiheke Island). Children (less than 15 years of age) were not included in the National Nutrition Survey because the NNSTAC recommended that methodologies would need to be developed specifically for children. The sample frame used in the surveys was an area-based frame. New Zealand is divided into 18,800 small geographic areas that are defined mesh block boundaries. These geographic areas are called primary sampling units (PSUs). Most PSUs contain between 50 and 100 dwellings, with an average size of 65 dwellings per PSU. The PSUs are divided into 122 strata according to various characteristics derived from the 1991 Census data. PSUs are first grouped according to 14 defined regions based on regional council boundaries. These regions are divided into Urban and Rural strata. These strata are further divided according into high/low Mдori population. Auckland and Wellington strata are further divided into high/low Pacific populations. Further stratification is made by clustering PSUs according to a number of other socioeconomic variables such as employment, education, age structure and family structure (eg, high proportion of sole-parent families). 8 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
A three-stage stratified design was used for the surveys. The required samples were chosen through a selection of: (i) a set of PSUs (ii) households within these selected PSUs (iii) a single respondent within a household. SELECTING THE POPULATION SAMPLING UNITS The PSUs used for the National Nutrition Survey and the New Zealand Health Survey were the same 1,752 PSUs that were being used for a separate Statistics New Zealand Survey ­ the Household Labour Force Survey. The selection of the PSUs for the Household Labour Force Survey was undertaken by drawing a simple random sample from each of the 122 strata described above. SELECTING HOUSEHOLDS WITHIN POPULATION SAMPLING UNITS A list of all private households in each selected PSU was constructed. Within each PSU, a random selection of households was taken. This selection was made in such a way to ensure an even geographic distribution of selected households across the PSU. Approximately 9,000 households were selected in this manner for the health and nutrition surveys. The set of National Nutrition Survey and New Zealand Health Survey PSUs did not fall uniformly across the various population subgroups for which estimates were required, as defined by the objectives. Therefore, selection of extra Mдori and Pacific households was required. An additional sample of 1,600 was selected to boost the Mдori and Pacific people's sample in the New Zealand Health Survey. Within the 1,752 PSUs originally chosen from the Household Labour Force Survey sample, a number had recently participated in the Household Labour Force Survey. Where the Household Labour Force Survey data showed that the household contained Mдori or Pacific adults, these households were screened for inclusion into the New Zealand Health Survey. Nine hundred adult Mдori households and 700 adult Pacific households were visited by a New Zealand Health Survey interviewer and asked to participate in the New Zealand Health Survey. Only Mдori or Pacific people from such households were eligible to participate in the New Zealand Health Survey. None of these households were part of the original 9,000 selected for the surveys. SELECTING A SINGLE RESPONDENT WITHIN A HOUSEHOLD One adult was randomly selected from each household by first ranking all eligible adults in the household by age, and then selecting a person based on a random number selection table. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 9
SAMPLE SIZE This publication was written while the surveys were still under way, and therefore accurate sample size numbers were not available. Approximately 10,600 households were selected to participate in the New Zealand Health Survey, of which about 8,500 would ultimately participate. From this New Zealand Health Survey sample it was expected that 6,000 New Zealand Health Survey respondents will consent to having their name passed on to the National Nutrition Survey, of which about 5,000 would ultimately participate in the National Nutrition Survey. The oversampling of Mдori and Pacific people in the New Zealand Health Survey was designed to achieve completed health survey interviews for 1,200 Mдori and 600 Pacific people. The number of Mдori and Pacific people completing the National Nutrition Survey was dependent on the response rate for these groups.
SAMPLE GROUPINGS FOR ANALYSES
The New Zealand Health Survey sample frame was designed to allow national estimates to be obtained for the following groups in the New Zealand Health Survey:
·
gender (male; female)
·
age group (15­ 44; 45­64; 65+; all ages)
·
ethnicity (Mдori; Pacific; Other)
·
regional health authorities (Northern; Midland; Central; Southern)
·
urban/rural (main urban; secondary urban; minor urban; rural)
·
Community Services card (hold; do not hold)
·
gender by ethnicity; age group; regional health authority; urban/rural
·
gender by ethnicity (Mдori; non Mдori) by age group.
Within all of the subgroups listed above, estimates for the New Zealand Health Survey will have an accuracy of 10 percent absolute error or less. That is, for a given prevalence, the 95 percent confidence interval is smaller than the given prevalence +/- 10 percent. Due to the nature of the sampling frame accuracy estimates could not be calculated for the National Nutrition Survey.
TIMING OF SAMPLING The New Zealand Health Survey interviews began on 14 October 1996 and continued to October 1997. The allocation of interviews for the 10,600 households was evenly spread throughout the 12-month period. Similarly, the 10,600 households were evenly spread across the geographic area of New Zealand. Interviewing for the National Nutrition Survey began on 2 December 1996 and continued to November 1997. Tight timeframes made it impossible to begin any earlier than this as the methodologies were not fully developed. This time lag between the two surveys was caught up in the early months of the National Nutrition Survey so that a time delay of approximately five weeks existed between interviews for the surveys.
10 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
HOUSEHOLD CONTACT Prior to the National Nutrition Survey, respondents to the New Zealand Health Survey were asked if they may want to participate in the National Nutrition Survey. Written consent was required to hand over the participants name, address, phone number and other minor details to the University of Otago. A team leader for the National Nutrition Survey telephoned each participant (or visited if a telephone was not connected) to arrange an interview time for the National Nutrition Survey. The team leader used a `contact form' supplied by the University of Otago to access information about the participants. Included in this form was the selected day for the interview. This was to ensure an even coverage for all seven days of the week over the duration of the survey. The team leader attempted to make the interview on that day, but where this was not possible, a day as close as possible to the selected day was chosen. NON-RESPONDENT INFORMATION For those people who participate in the New Zealand Health Survey but not the National Nutrition Survey, the Ministry will have access to their full socio-demographic profiles. For those people who do not participate in the New Zealand Health Survey there will be a small amount of information available for people who complete the household information sheet and do not complete the survey. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 11
METHODOLOGIES PRETESTING THE NATIONAL NUTRITION SURVEY METHODOLOGIES The methodologies underwent pretesting in two field trials. The first field trial occurred in Dunedin and Rotorua during August 1996. The objectives of the first field trial were: · testing whether the questionnaires flow well and whether the individual questions were clear · measuring the time to complete the different components · testing whether the order of the questionnaires and measurements were appropriate · determining how the participants reacted to the different components · determining the participants' understanding of the consent forms and the information pamphlet · testing the response rate · testing the interaction between the New Zealand Health Survey and the National Nutrition Survey · testing the procedure of the New Zealand Health Survey interviewers leaving the `Your usual food intake' questionnaire · testing the courier system for the transport of blood · determining the procedures and questionnaires were appropriate for Mдori people. The sample drawn for the trial was supplied by Statistics New Zealand as part of the New Zealand Health Survey field test. Fifty people from the New Zealand Health Survey trial (out of 62) consented to having their names passed on to the National Nutrition Survey and 38 people were interviewed, including 15 Mдori. All methodologies, training manuals and equipment underwent considerable further development as a result of the first field test. Interactive procedures between the New Zealand Health Survey and National Nutrition survey were also tested and refined. The second field trial occurred in Auckland in September 1996 to trial the National Nutrition Survey on Pacific people. The objectives of the second field trial were: · determining the procedures and questionnaires were appropriate for Pacific people · continuing pre testing the methodologies. 12 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
Sampling for the Auckland field trial was not random, nor was it linked to the New Zealand Health Survey. The trial sampled 33 Pacific people from a range of ethnic groups (Tongan, Niuean, Samoan and Cook Islands). Fifteen full interviews were undertaken, and 18 interviews focused on specific aspects of the methodology. Additional pretesting of the food security and environmental chemicals sections was conducted on a further 16 people in Northland. A glossary of common foods eaten by Mдori and Pacific people was prepared to ensure interviewers were familiar with alternative names for these common foods. The qualitative food frequency questionnaire underwent pretesting in a separate study from the two field trials because of the timing of contracts with the University of Otago. One aspect of the qualitative food frequency questionnaire that was included in the field trials was the method of presenting the questionnaire to participants. In the first field trial the New Zealand Health Survey interviewer left the questionnaire with the participant. Over 50 percent of questionnaires had to be replaced because they were lost during the three-week gap before the National Nutrition Survey interview. A decision was made to post the questionnaire to participants with a letter of introduction, just prior to the National Nutrition Survey interview. For more information on the pretesting for this questionnaire, see the `Your usual food intake' questionnaire section. The pretesting of the food security indicators in the first field trial showed that the questions were misunderstood and viewed with suspicion by the participants. It was decided to provide statements rather than questions. For example, `food runs out in my household due to lack of money', the respondent chooses from: often, sometimes, never. The pretesting also identified a lack of understanding by the interviewers of the concept of food security which was subsequently reflected in their interviewing style. More comprehensive training of the interviewers was undertaken and the interviewer training manual section on food security was expanded. Interviewers were encouraged to ensure that questions were not perceived as judgemental or threatening. This was achieved through a verbal explanation provided for the interviewer to read prior to each food security indicator statement. During pretesting of the blood pressure methodology, the acceptability to respondents of three repeat measurements was assessed as some members of the NNSTAC felt that two measurements would be more acceptable. Blood pressure measurements appeared to cause no discomfort in the pretesting so three readings were recommended for the National Nutrition Survey. The University of Otago also conducted separate tests involving six individuals being measured by four different OMRON blood pressure monitors and a Hawksley Random Zero machine. After analysing the data in a two-factor analysis it was confirmed that three measures should be taken and the results averaged. The measurement of bioelectrical impedance was pilot tested. Resistance and reactance was measured on a BIA ­ 101 RJL system analyser (RJL-systems Detroit) with a 50 kHz, 800 µA device, following the instructions of the manufacturer. The intention was to use the measurements of bioelectrical impedance in predictor equations for body fat mass. A study looking at Mдori and Samoan people in Auckland measured body composition using Dual-Energy X-ray Absorptiometry (DEXA). Predictor equations for body fat mass using skinfold measurements, bioelectrical impedance and anthropometric measurements (weight, height) were also developed. The results showed that the differences between body fat mass estimated by the regression equations and those measured by DEXA were small (less than 1.0 kg) for all methods. Bioelectrical impedance did not produce estimations of body fat mass that were significantly better than equations using skinfold measurements or anthropometric measurements (Swinburn et al 1997). The results from the pilot-testing indicated that many homes did not have a suitable place for the measurement to take place. These problems led the NNSTAC to recommend against the inclusion of bioelectrical impedance in the National Nutrition Survey. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 13
THE ORDER OF SURVEY METHODOLOGIES The following order for the various methodologies was used: · `Your usual food intake' questionnaire posted out and self-completed · multiple-pass 24-HDR · dietary supplements · `Your usual food intake' questionnaire checked · barriers to dietary change · food security · environmental chemicals · blood pressure · anthropometric measurements · blood samples. The `Your usual food intake' questionnaire was mailed to the participant by the University of Otago for the participant to fill out before the National Nutrition Survey interviewer arrived. The multiplepass 24-HDR was the primary methodology and was undertaken first during the home interview. This ensured that if the interview was cut short for any reason, the multiple-pass 24-HDR data would have been collected. It also established rapport between the interviewer and the participant before completing more intrusive methodologies. Dietary supplements, barriers to dietary change, food security and environmental chemicals questions were also interviewer-administered and naturally flowed on from the 24-HDR. The `Your usual food intake' questionnaire was checked by the assistant before the barriers to dietary change questions were asked. This is because responses in the `Your usual food intake' questionnaire were required for answering certain barriers to dietary change questions. Blood pressure had to be measured after 30 minutes' rest, and taking it directly after the respondent had spent time answering the 24-HDR, and other interviewer-administered questions ensured this. Anthropometric measurements were then completed, before taking the blood samples ­ the methodology that was perceived to have the highest respondent burden. All methodologies were voluntary. Participants were able to decline participation for any particular methodology. INTERVIEWERS Two people were used in the National Nutrition Survey to conduct the home interviews with participants. Each interviewer underwent a two-week training programme covering all of the methodologies in the National Nutrition Survey. The interviewer was the main person responsible for carrying out all methodologies. The assistant underwent a two-day training programme covering certain aspects of the methodologies in the National Nutrition Survey. The assistant's role was to assist the interviewer wherever possible. The interviewer and assistant also worked in pairs for security And safety reasons on the advice of the New Zealand Police and to meet the University of Otago's obligations under the Employment Contracts and the Occupational Safety and Health Acts. 14 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
MULTIPLE-PASS 24-HOUR DIET RECALL METHODOLOGY This was the primary methodology used in the National Nutrition Survey. A 24-HDR is a quantitative record of all foods and drinks the participant consumed the previous day, covering a 24-hour duration from midnight to midnight. This includes all foods and drinks consumed both at and away from home. Significant discussion went into what would be the most appropriate methodology to meet the objectives outlined for the National Nutrition Survey. Options included food records, a 24-HDR, or a quantitative/ qualitative food frequency questionnaire. The main focus of the survey was to meet the information needs of the Ministry of Health, and because the information was to be used in a variety of ways, a multiple-pass 24-HDR as the primary methodology was most appropriate. There were a number of logistical reasons that meant that food records would be unsuitable to the sampling method imposed by the unison of the New Zealand Health Survey to the National Nutrition Survey. Furthermore, the number of participants required to ensure accurate data for all ethnic and socio-demographic characteristics made food records too expensive as an option. The prime function of the Ministry of Health is to provide evidence-based policy advice to the Government. For food and nutrition policy, there was a need for detailed food and nutrient intake information. It must be emphasised that food intake was a core requirement of the methodology. Previous nutrition surveys in New Zealand had a significant focus on nutrient intake. Food intake information is required for dietary modelling work, which in turn can be used in many regulatory areas, such as contaminant monitoring and monitoring changes to the food supply. This is particularly important in New Zealand where a joint food standard-setting system was agreed to by the Australian and New Zealand Governments in 1995, and commenced in July 1996 . As part of an effort to harmonise food standards with Australia, New Zealand food manufacturers and importers are now allowed to fortify a range of foods with an increased number of vitamins and minerals. When agreeing to this new system, the New Zealand Government approved funding to monitor the effect of the increased fortification of New Zealand foods on the health of the New Zealand population. It was therefore necessary to collect very detailed information on food intake to gather baseline data, allowing future assessment of the fortification policies. In particular, brand names of foods had to be collected where legislation permitted foods to be fortified. These data can be further analysed to monitor the changes that fortified foods have had on the population's nutrient intake. The Ministry of Health also realised the importance of foods as set out in the Food and Nutrition Guidelines for Healthy New Zealanders. These are food-based guidelines which provide a recommendation on the number of servings that should be consumed from each of the major food groups by healthy individuals. Food intake data were required to assess whether New Zealanders were meeting these recommendations. The potential use of the 24-HDR food intake data by food manufacturers and producers, and pharmaceutical companies was not a key consideration when selecting the 24-HDR methodology. However, the food-based data are likely to be of significant interest to these groups and other private companies by providing data about the use of specific products. Food-based information was also a major requirement to ensure that recipes of foods, such as vegetarian lasagne, and foods eaten in combination, such as toast and butter, are adequately coded. This will allow a description of eating habits, such as `what foods commonly have fat added to them?', and `what type of fat is added?'. It will also allow more accurate matching of foods to nutrient lines in the New Zealand Food Composition Database (NZFCD), which will increase the accuracy of the nutrient intake data. Similarly, detailed food portion size data were required, not only to increase the accuracy of the nutrient intake data, but also to provide estimates on portion sizes eaten in New Zealand. The Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 15
data from the multiple-pass 24-HDR methodology will provide this information about participants' food habits. The cultural diversity in New Zealand was a significant factor in the need to use a food-based system to collect dietary information. Mдori and Pacific people were two of the main ethnic groups sampled and a flexible system to account for all foods consumed by participants was required. The multiplepass 24-HDR methodology is designed to record whatever the participant consumes, regardless of the participant's culture. Nutrient intake information was also of significant interest to the Ministry of Health. In particular, the Ministry required national estimates on the nutrient intake from basic food items and the total nutrient intake from food for population groups. The National Nutrition Survey is the principal method for providing this detailed nutrient intake data on a national sample. The nutrient information will contribute to several Ministry of Health publications, including the annual Progress on Health Outcome Targets report and the five-yearly health status and health determinants reports. Nutrient data will be used as reference data for the population at large and to estimate the prevalence of dietary intake above and below specific points such as the recommended dietary intakes (RDIs). Examining trends over time between the 1977, 1989/90 and current National Nutrition Survey, will be possible for nutrient intake data. The information requirements of the Ministry of Health dictated that a 24-HDR methodology be used as the primary methodology in the National Nutrition Survey. The multiple-pass 24-HDR methodology drew on techniques used in the United States Department of Agriculture's-Agriculture Research Services, Continuing Survey of Food Intakes by Individuals' 24-HDR (Cypel et al 1997; Guenther et al 1995) and the Australian Commonwealth Department of Health and Family Service's Australian Nutrition Survey 24-HDR (Brown et al 1995; Bloom et al 1995). These methodologies focused on an open-ended collection of all foods eaten by a participant and were developed to reduce under-estimation of dietary recall. The multiple-pass 24-HDR gave the interviewer maximum ability to collect the information on foods, as consumed by the participant, which supplies maximum food-based information, as required by the Ministry. The NHANES III 24-HDR methodology developed by the University of Minnesota's Nutrition Coordinating Center was examined because it was a direct data-capture programme (McDowell et al 1990). The University of Otago decided to develop a new direct data-capture programme to reflect the unique needs of the New Zealand National Nutrition Survey. The multiple-pass 24-HDR methodology was a direct data-capture programme developed by the University of Otago. The programme was designed to match foods consumed by participants to a food-list database. The preparation of the food-list database was a major step in the development of the programme. Several steps were taken to prepare the food-list database. · The Australian National Nutrition Survey food-list database was purchased. · The list was modified to reflect New Zealand's unique food supply by: ­ deleting foods not permitted or available in New Zealand ­ adding unique New Zealand foods ­ consulting AC Nielsen packaged foods sales data ­ consulting Producer Boards for primary produce such as meat, dairy, fruit and vegetables ­ perusing foods available in supermarkets ­ consulting with Mдori and Pacific groups. At the start of the survey the food list contained approximately 9,000 foods and 5,000 recipes. 16 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
CARRYING OUT THE MULTIPLE-PASS 24-HDR The basic outline of the multiple-pass 24-HDR followed a three-step interview process. The first pass is termed the quick list. This was a list of all the foods eaten in the 24-hour period by the participant. The quick list was entered directly into the computer. The recall of the foods by the participant occurs in any order ­ for example, chronologically, by meals, by occasion ­ whichever method the participant chooses. The second pass is termed the detailed description. The computer recalled all the foods in the quick list, one by one, allowing the interviewer to collect detailed information about each food. This included a detailed description of the food, the cooking method, when it was eaten, the amount eaten, and whether it was eaten in combination with other foods. If the food was a packaged food and had a barcode, the interviewer could use the computer's bar code scanner to scan in the barcode of the food. The barcode scanner was a further option available to the interviewer to record the food description. A detailed food-list database existed within the computer to help the interviewer identify the food that the participant consumed. Specific prompt questions were built into the computer software so that when a particular food was recalled, specific questions were asked for that food. The above technique identified each food consumed by the participant to a level of detail required for brand name identification (where required) and matching to the NZFCD at a later date. The interviewer was able to match most foods directly to the computer's food list at the interview. This removed the need for lengthy descriptions of foods or coding of foods at a later date. The objectives of the National Nutrition Survey included collecting detail on both food and nutrient intakes of New Zealanders. Having an extensive food list enabled considerable detail on food consumption to be obtained. If foods had been coded at an earlier stage to the nutrient lines of the NZFCD much of this food data would have been lost. Examples of the probe questions for a participant who had a glass of milk entered on their quick list are: · at what time did you have your milk? · was anything added to your milk just before you drank it? (This prompts the participant to remember any other foods that have not already been recalled and allows combinations of foods to be recorded.) · do you know the brand and product name of the milk? (This provides an accurate description of the food and is especially important in food groups which may contain foods fortified with vitamins and minerals.) · if no (to the above question). What kind was it? (The reply categories include many possible types of milk. For example, trim milk < 0.5 percent fat, homogenised standard milk 3.5 percent fat, etc.) · was it ready to drink, a fluid made from a powder, or a powder? · how much of the milk did you actually have? If a food could not be matched accurately to the food-list database the interviewer was able to describe the food in a `notepad' within the programme for later identification by nutrition staff at the University of Otago. The interviewer could also use the notepad to record additional details even if a food was identified on the food list. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 17
Food and beverage measures such as cups, spoons and sticks, and photographs were used to help the respondent identify portion volumes and weights. Photographs of take-away containers, spreads on bread, and other similar photographs were used to help the participant describe serving sizes. Thickness sticks were used to estimate thickness of foods such as meat, fish, poultry and cheese. Grids and concentric circles were used to estimate the size of larger objects. Balls were used by the participant to estimate circular foods such as apples and oranges. Dried beans were used to describe the size of mounds of foods such as mashed potato and rice, and to describe the volume of soft foods and beverages. A help file of standard serving sizes of foods and weights was used to help estimate the size of the portion consumed by the participant. Combinations of food as they were consumed were recorded. For example, that the participant consumed margarine with bread. Combinations are coded by the programme for: · beverages with additions · breakfast cereals with additions · savoury baked products, bread and crackers with additions · sweet products (puddings, cakes and pies) with additions · vegetables with additions · soup with additions · other combinations (eg, meat pie with tomato sauce). If a food consists of different ingredients and the amount of each ingredient is known, then the food can be recorded as a `home recipe'. If this detail is not known then a food can be recorded as a `standard recipe' providing the food matches a recipe on the recipe-list database. A food can be recorded as a `modified recipe' when the participant knows the major ingredients but not the exact amounts used. Questioning about `modified recipes' focussed on gaining information about ingredients likely to contain fat. For example, if the participant ate lasagne, they were asked to identify the main ingredients in their lasagne (meat or vegetables, etc) and the type of fat and/or milk and/or cheese used. The third and final pass in the 24-HDR is called the review. The interviewer reviewed the detailed recorded intake. This acted as a check for both interviewer and participant. The interviewer reviewed what was eaten in a chronological order and asked if anything else was eaten, besides the foods recorded. The interviewer also clarified the portion sizes reported. New foods could be added or deleted at this time and weights/volumes could be edited, or at any other stage in the interview. Data collection was standardised because the probe questions appeared on screen and the interviewer could not move on to the next question until an answer was entered. Any discrepancies flagged by the direct data-entry system or queries about foods entered on the notepad were followed up with an interviewer as each diet record was checked by University of Otago nutrition staff. REPEAT SAMPLE Within-person variation in a person's nutrient intake data occurs naturally due to the day-to-day variety in people's food intake. Variation in nutrient intake necessitated a subsample of National Nutrition Survey participants undergo a second multiple-pass 24-HDR. Calculations can be made when individual repeat samples are taken to reduce the distribution (spread) of each nutrient for the population. This was especially important because the 24-HDR nutrient intake data were to be used for estimating the 18 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
prevalence of dietary intakes above and below RDIs. Making these population adjustments for withinperson variation allowed a more reliable estimate of risk of inadequate or toxic intake to be made. The number of people included in the repeat sample had to be large enough to estimate the withinperson variation in the participants' diets. It is important to note that the within-person variation is determined on an individual basis and then calculated for the entire sample. Ideally, every participant would be resampled, but increasing the numbers of participants in the resampling beyond a certain level adds little extra predictive value. The number to resample was based on similar international surveys as mathematical formulae to estimate the number of participants to resample are extremely complex. The Australian Nutrition Survey resampled one in ten participants, out of a total sample of 13,800 people, returning 1,380 participants. After consultation with statistical experts, it was decided that the New Zealand National Nutrition Survey should resample approximately 600 participants. Repeat interviews took place within three weeks of the first National Nutrition Survey interview. Seasonality was an issue that was discussed regarding the repeat sample. It was decided that seasonal variability could confound the within-person variability. The logistical problems of repeat sampling in a different season during a 12-month survey, and the logistical problems of tracking participants between season were considered too great. It was decided, for logistical reasons, that participants would undergo the repeat sample within one month. This would allow future interviews to be arranged at a similar time in the area to reduce travelling expense associated with collecting the repeat 24-HDR. The interviewer who undertook the repeat sampling was usually the same interviewer who undertook the original 24-HDR. This further limited intra-interviewer variability. This was designed to increase the response rate for the repeat 24-HDR if rapport already existed between the interviewer and the participant. If the original interviewer was not available to undertake the repeat 24-HDR, then a different interviewer was sent. To maximise the within-person variability of dietary intake a different day of the week from the original 24-HDR interview was selected for the repeat 24-HDR. If the original 24-HDR was on a weekday, then the repeat sample was asked to occur on a weekend day, and vice versa. Where a different day of the week could not be arranged then the repeat 24-HDR took place on the same day of the week as the original 24-HDR. Urban/rural differences for within-person variability are unknown in New Zealand. However, differences in urban/rural food and nutrient intakes were minimal in the LINZ® survey. It was decided for the National Nutrition Survey that only people in urban areas would be eligible to be asked to undergo a repeat 24-HDR, as repeated visits to rural areas would incur an unsustainable cost for the survey. ANALYSIS OF DATA The New Zealand Food Composition Database (NZFCD) will be used to analyse the data collected in the multiple-pass 24-HDR. At present, the database contains information on 52 core nutrients for approximately 2,000 foods. The quality of the nutrient intake information from a 24-HDR is dependent on a number of factors, of which the number of foods on the NZFCD and the quality of data are significant. Crop & Food Research Ltd maintains the NZFCD and will assist the University of Otago with the nutrient analysis of the multiple-pass 24-HDR and matching of the food list to nutrient lines in the NZFCD. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 19
The multiple-pass 24-HDR will generate data on what foods New Zealanders eat. Each food eaten will be matched to a food on the NZFCD for nutrient analysis. The number of foods on the NZFCD will be expanded in a variety of ways: · analysis of foods · derivation of nutrient composition from ingredients of dishes · information from overseas food composition databases. It is not feasible to have nutrient data for every food or dish eaten, so criteria were developed to decide how foods from the multiple-pass 24-HDR will be matched to foods on the NZFCD (Appendix 1). After four months, preliminary data from the survey were used to establish the frequency with which foods from the food list and `new' foods recorded on the notepad were being consumed. On the basis of this information, the list of foods which the NZFCD would analyse was revised and updated. Two other projects relating to food composition will provide information for the NZFCD and the National Nutrition Survey. 1. Fortified foods Fortification of a range of foods with vitamins and minerals is now permitted in New Zealand. The Ministry of Health has a commitment to monitor the potential health impacts of consuming fortified foods. A project to monitor fortified foods available for sale in New Zealand has been purchased by the Ministry of Health from the Therapeutic Database (TDB). The TDB also collects information on ingredients in manufactured foods. 2. Vitamin and mineral supplements Information on composition of vitamin and mineral supplements is being collected in a separate project purchased by the Ministry of Health from the Institute of Environmental Science and Research Ltd (ESR). The data collected by ESR will be included on the NZFCD. DIETARY SUPPLEMENTS The NNSTAC recommended that quantitative information be collected on dietary supplement intake. The committee considered it was important to collect this information because cases where dietary supplement intake was high would significantly impact on total nutrient intake. The information on dietary supplement intake is collected in two ways: quantitatively for the previous 24 hours; and qualitatively for consumption over the past year. The information on dietary supplement intake during the previous 24 hours is collected separately from the multiple-pass 24-HDR. At the time when the food-list database for the 24-HDR was developed, it was not possible to include a complete list of dietary supplements, so it was decided to ask the question separately. The results from the dietary supplement questions are recorded electronically and nutrient intake from dietary supplements will be assessed. Information is collected on brand name, description (amino acid, multi-mineral, etc) and quantity consumed. There are two show cards, providing examples of vitamin and mineral supplements and other supplements. The show cards are used to help the participant accurately describe the type of dietary supplement consumed. A printed example of the dietary supplement questions and show cards are attached as Appendix 2. 20 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
`YOUR USUAL FOOD INTAKE' QUESTIONNAIRE The `Your usual food intake' questionnaire contained the qualitative food frequency questionnaire (FFQ) and key food habits questions. Controversy surrounded the selection of a qualitative FFQ for use in the National Nutrition Survey rather than a quantitative FFQ, as discussed below. The requirement for a FFQ in the National Nutrition Survey was to provide an estimate of the participants usual food intake over the preceding 12 months. This will provide complementary data to the multiple-pass 24HDR in a quick and easy format, allowing simple analysis of food consumption patterns. The questionnaire also included a number of questions asking about the key food habits of the participant; hence the FFQ in the National Nutrition Survey was titled `Your usual food intake'. The additional key food habit questions were developed after examination of similar LINZ® survey and Australian questions, and consultation with the NNSTAC. These questions focus on food habits which have a significant effect on the nutrient intake of a person. For example, type of fat used in cooking and type of bread eaten. These questions can be used in the future to estimate whether potential health promotion strategies are being effective. Using a small number of questions to determine if the population's diet is changing will be significantly simpler than completing an extensive multiplepass 24-HDR. QUANTITATIVE VERSUS QUALITATIVE FOOD FREQUENCY QUESTIONNAIRE Significant discussion was held around the issue of a quantitative versus qualitative FFQ. This stemmed from the wide use of quantitative and semi-quantitative FFQs in epidemiological research. In New Zealand, a quantitative FFQ had already been used in several major studies. Several points were considered in determining the type of FFQ to be used in the National Nutrition Survey. Historically, data collected from FFQs have been used in a variety of ways, including: · estimating intakes of individual or selected nutrients · determining intake of specific food groups (eg, fruits and vegetables) · monitoring trends in dietary patterns over time · determining quartiles of nutrient intake · ranking of individuals by nutrient intakes · estimating mean nutrient intakes. However, not all FFQs are developed equally and their uses have reflected this. It is widely agreed that a qualitative FFQ should only be used to collect data on single nutrients, determine the intake of specific food groups and monitor trends in dietary patterns over time (Bergman et al 1990; Sempos 1992). Qualitative FFQs are often used in conjunction with other methods of dietary assessment such as the 24-HDR. Quantitative FFQs can perform the same functions as the qualitative FFQ, but additionally, they have been used for the latter three purposes listed above. Not all of these purposes were relevant in the National Nutrition Survey because the multiple-pass 24-HDR provided this information. While quantitative FFQs are the method of choice in large-scale epidemiological studies, this did not imply that the National Nutrition Survey should use one. Quantitative FFQs are appropriate to meet only limited and predefined objectives. The National Nutrition Survey is not an epidemiological study and its goals, objectives and resources reflect this. Finally, a qualitative FFQ reduces the burden on participants because decisions on portion size are not required. It also shortens the time required to complete the survey, reducing overall respondent burden which may improve the response rate for the survey. Therefore, a qualitative FFQ was chosen for the National Nutrition Survey. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 21
OBJECTIVES OF THE FOOD FREQUENCY QUESTIONNAIRE The qualitative FFQ had a number of specific objectives. · To produce information covering all of the major food types in the New Zealand food supply about the usual food intake of the population. · To estimate the percentage of New Zealanders consuming at least six servings of breads and cereals, and at least five servings of Vegetables and fruits, each day. · To be coded by optical scanning equipment. To ensure that these objectives were achieved, the food lists for the National Nutrition Survey FFQ were based on all available information. The initial work began by generating a list of all foods consumed by greater than 1 percent of the population from the LINZ® survey 24-HDR data. Pretesting among Mдori and Pacific groups was very valuable in expanding the food list for Mдori and Pacific people's eating patterns. Additional work was carried out by seeking input from a wide variety of individuals and organisations and by examining other FFQs used in Australia and New Zealand. F O R M AT One questionnaire was used for all survey participants, regardless of age, gender and ethnic group, and the questionnaire was designed for a reading age of 10 years. The frequency-of-use format used in the FFQ was a multiple-choice format. Previous experience from the development team suggested that multiple-choice formats were easier to use than coded formats. The need for the questionnaire to be optically scanned also necessitated a multiple-choice format. The number of frequency-of-use categories included in the FFQ was eight for all questions except the drinks category, which required only seven (and included 6 + times per day, which was not useful for any other food category). It was necessary to provide enough categories for participants to adequately estimate their frequency of consumption, at the same time as not overwhelming participants with too many options. PRETESTING Pretesting of the FFQ occurred in Dunedin, Whangarei and Auckland. The pretesting used focus groups in which volunteers were asked to complete the questionnaire two pages at a time. After each two pages were completed the participants were asked how they answered each question and whether they were confused about any aspects. The interviewer was able to detect any misunderstanding of questions because of their knowledge about the intended meaning of each question. REPEATABILITY STUDY A repeatability study was conducted to determine the reliability or reproducibility of the FFQ. This was a measure of the FFQ's ability to achieve the same (though possibly wrong) results when administered on two occasions. It was not a measurement of validity for the FFQ. Assessment of validity requires comparison of the FFQ against a gold standard measure of dietary intake in which the errors of dietary assessment between the two methods are as independent as possible to avoid over-estimating the validity. As an example, a diet history would not be a good method to act as a comparison because the types of error, such as memory and understanding of questions, are similar. Food records kept for a suitable number of days to accurately estimate intake would be a suitable comparison method for validating a FFQ. However, assessing validity for the food-based qualitative FFQ used in the National Nutrition Survey was unable to be carried out within the tight timeframes. 22 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
The repeatability study was undertaken on a mix of males and females from a range of age groups and socioeconomic backgrounds. There were 35 Mдori, 37 Pacific and 38 Pдkehд subjects in the repeatability analyses, totalling 110 people. The second administration occurred three weeks after the original administration and included a question about diet or weight change since the original administration. Any subjects who indicated they had changed their diet or their weight were excluded from the analyses on the basis that they may have changed their diet. Each food item was analysed based on the percentage of respondents whose responses on the two occasions fell within the same frequency-of-use category or within one frequency-of-use category. On average, the level of exact agreement in the reported frequency of consumption was 52 percent for Mдori, 59 percent for Pдkehд and 43 percent for Pacific people. When the adjacent category was also included, the level of agreement was 82 percent for Mдori, 89 percent for Pдkehд and 73 percent for Pacific people. Across the sample, gender did not affect repeatability of response. On average, 52 percent of men and women produced exact agreement on two occasions in their reported frequency of consumption of food items. The results of the repeatability study suggest that caution should be used when interpreting FFQ responses from Pacific people. The percentage of subjects whose responses differed by more than one category was 23 percent for the Pacific people, compared with 17 percent in Mдori and 10 percent in Pдkehд. While repeatability is poorer for the Pacific people, it is not significantly different from that in overseas studies. The results of the repeatability study prompted refinements to the FFQ to make it simpler and improve data quality. COMPLETING THE QUESTIONNAIRE The qualitative FFQ is titled `Your usual food intake' in the National Nutrition Survey. It is an optically scanned document which requires a pencil and eraser to be supplied with the questionnaire. All errors and stray marks had to be erased completely and the questionnaire should not have been folded or bent. `Your usual food intake' was mailed to the participant by the University of Otago for the participant to fill out before the National Nutrition Survey interviewer arrived. This had several advantages. Firstly, it removed a long questionnaire from the main interview time, significantly reducing perceived respondent burden. Secondly, it allowed the interviewer to check the `Your usual food intake' questionnaire for mistakes, gaps and multiple responses to questions. If the participant had not filled out the `Your usual food intake' questionnaire, then the interviewer waited until it was completed, and helped where necessary. This added significant time to the interview, but ensured a high completion rate for this questionnaire. Testing was not undertaken to determine if completion of the FFQ before the 24-HDR influenced responses to the 24-HDR. Any influence caused by this was considered to be uniform because the methodologies were completed in the same order by all participants. The initial questions in the `Your usual food intake' questionnaire covered the key food habits of participants and the number of servings from the fruits and vegetables, and breads and cereals food groups. The servings of fruit and vegetables could be separated into fruit consumption and vegetable consumption. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 23
Key food habit questions covered a range of important topics: · the eating pattern of the participant, for example, lacto-ovo vegetarian · servings of fruit per day · servings of vegetables per day · slices or rolls of bread (and toast) per day · type of bread eaten most often · servings of foods such as pasta, rice, muesli, porridge and breakfast cereals per week · whether the participant usually eats breakfast cereal and if so, what type · whether the participant eats meat fried or roasted in fat and if so, what type · whether the participant eats vegetables fried or roasted in fat and if so, what type · whether the participant drinks or uses milk and if so, what type · whether the participant uses butter or margarine on bread or crackers and if so, what type · whether the participant eats red meats and if so, whether they trim off excess fat · whether the participant eats chicken and if so, whether they remove the skin · whether the participant eats eggs and if so, how many per week. The remaining questions in the `Your usual food intake' questionnaire covered frequency of consumption of a number of categories of foods. They were: · dairy foods · bread and cereal foods · meat and fish · miscellaneous · dressings and sauces · vegetables · fresh fruits - when they are in season · other fruits · drinks. For seasonal foods such as certain fruits, where consumption may have been variable throughout the year, subjects were able to estimate their usual consumption when each item was in season. Subjects decided which items were seasonal for them. This reduced the complexity of the questions for participants. Questions for frozen, dried and canned fruits were separated from fresh fruits in season, to avoid confusion for the participant. Certain questions in the `Your usual food intake' questionnaire gave the participant the opportunity to enter an `other' selection. The cultural diversity in New Zealand required this more open format, to adequately allow all participants to describe their usual food intake accurately. A copy of the `Your usual food intake' questionnaire is attached as Appendix 3. 24 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
BARRIERS TO DIETARY CHANGE To provide a basis for nutrition education and other strategies to improve nutrition, a series of questions on participants' barriers to dietary change were required. These questions focused on main themes from the National Plan of Action for Nutrition (PHC 1995): · to increase consumption of fruits and vegetables · to increase consumption of breads and cereals · to reduce dietary fat intake. The questions were developed to allow assessment of the difficult aspects of making dietary changes, the percentage of people currently making a change, and the number of people thinking about making a change in the next six months. The barriers to dietary change can be analysed separately as perceived barriers (for those people who are thinking of making a change) and actual barriers (for those people who are making a dietary change). The questions were worded to avoid a judgemental interpretation. This was very difficult to achieve and pretesting was extremely valuable. Presenting categories of foods to participants may suggest to the participant that these are the food groups that they should be changing. However, these food groups are widely used in recommendations and health promotion and so it was sensible to use these categories. Presenting an open-ended question such as `Are there any foods which you are trying to eat more, or less, of?' would have provided a wide range of answers, making coding very difficult. To ease the coding of the questions the responses were pre-coded. This still allowed responses in the `other' category. Participants were asked about their barriers to dietary changes if: EITHER · they were not meeting the Food and Nutrition Guidelines for Healthy New Zealanders for fruits and vegetables, breads and cereals OR · they were meeting the Food and Nutrition Guidelines for Healthy New Zealanders but were currently trying to change their eating behaviour. All participants were asked about barriers to lowering their dietary fat intake, because at the time of the interview it was not possible to determine whether or not participants were following the recommendation. To determine whether participants were meeting the Food and Nutrition Guidelines for Healthy New Zealanders for fruit and vegetables, and breads and cereals intake, the answers to questions 1, 2, 4 and 6 of the `Your usual food intake' questionnaire were transferred to questions 1, 2 and 3 in the `Barriers to dietary change' section. This allowed more direct questioning in the `Barriers to dietary change' section because previous eating patterns were known. Question 4 in the `Barriers to dietary change' section asked participants whether they were making any changes to their diet at present. If participants answered `yes', then questions 5, 6, 7, 8 and 9 probed what type of change participants were trying to make to the appropriate food group: fruits; vegetables; breads and cereals; butter/margarine/oils. Question 10 asked participants whether they were thinking about making any changes to the foods they would eat in the next six months. If participants answered `yes', then questions 11, 12, 13 and 14 probed what type of change participants were trying to make to the appropriate food group: fruits; vegetables; breads and cereals; butter/margarine/oils. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 25
Questions 15, 16 and 17 asked participants with low intakes of a food group (fruits; vegetables; breads and cereals) and participants who had stated in an earlier question that they were attempting to eat more from a food group, about the sorts of things they often found difficult about increasing consumption of that food group. All participants were asked question 18, about difficulties with cutting down on butter/margarine/oils or other foods high in fat. All questions were accompanied by show cards which the interviewer used to ensure questions were asked in an open-ended fashion and to help participants with responses. The difficult `skips' in the questioning process because of the branching questions were simplified by being computer-assisted. The computer carried out the correct skips depending on the answers given by participants. A printed example of the `Barriers to dietary change' questions and show cards are attached as Appendix 4. FOOD SECURITY INDICATORS `Food security' is an internationally recognised term that addresses issues surrounding access to the food people need for a healthy life. Traditionally, food security was linked to hunger and malnutrition in developing countries, however it is now recognised that increasing numbers of people in developed countries experience problems with access to the food they need, mainly due to lack of money. Food security encompasses the ready availability of nutritionally adequate and safe foods, and the assured ability to acquire personally acceptable foods in a socially acceptable way. The National Plan of Action for Nutrition (PHC 1995) identified food security as a priority area for research. This was on the basis of a growing number of anecdotal reports and the increasing amount of international evidence of its importance for good nutrition and health. The development of food security indicators included: · a review of the food security indicators currently being used in developed countries and the international experience in the use of food security indicators · identification of the key issues surrounding access to food for New Zealanders on a low income · development of food security indicator questions based on identified key themes · pretesting the food security indicators. The identification of the key themes surrounding access to food was via focus group interviews. Focus groups were conducted with Mдori, Pacific and Pдkehд people. All focus group participants were on low incomes and had major responsibility for food procurement and preparation in their household. The eight food security indicators were developed from five main themes. · Food insecurity, covering issues of hunger, stress over providing meals/food, restriction on the amount and type of food purchased because of lack of money, lack of access to food, (usually transport-related) and lack of money for food purchase because of the expense of other living costs. · Food inadequacy, covering issues of lack of choice of food and the resulting monotony of diet and restrictions in amounts of food eaten or provided, often resulting in going without food or meals for adults (particularly mothers) and restricted size of meals for children. 26 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
· Coping strategies, ranging from personal, emotional and Social Support and activities to compensate for lack of food or money to buy food. · Alternative sources, for both food and resources for food purchase when there is insufficient food because of lack of resources. These include the church, family/whдnau, friends, stealing, gardens, food gathering, selling personal belongings, the use of food banks and soup kitchens and the use of special benefits and food grants. · Cultural issues, although important in perceived food inadequacy, cultural issues appeared to be more important in aspects of hospitality and use of special traditional or cultural foods. Specific coping strategies, including sources of food, differed among different cultural groups, especially in terms of food gathering. The themes were generally consistent with most of the international experiences in food security except in the areas of coping strategies and hospitality. A printed example of the `Food security questions', including the verbal explanation proceeding each question and the show cards, are attached as Appendix 5. ENVIRONMENTAL CHEMICALS The organochlorine chemicals methodology was proposed and funded by the Ministry for the Environment. As discussed in an earlier section, the Ministry for the Environment required blood samples from a representative New Zealand population to undertake a cross-sectional survey of the background levels and body burden of persistent organochlorine chemicals. Organochlorines include poly chlorinated dibenzo-p-dioxins and poly chlorinated dibenzofurans (generically called dioxins), poly chlorinated biphenyls (PCBs) and pesticides such as DDT, aldrin, dieldrin and chlordane. Dioxins are produced as by-products of a number of industrial and combustion processes. PCBs were formerly used in electrical transformers, and the pesticides were once widely used in the agriculture and timber manufacturing industries. This study is a fundamental component of the Ministry for the Environment's larger Organochlorines Programme which aims to develop Resource Management Act 1991 national environmental standards for dioxins and guidelines for other organochlorine substances. The application of these standards will safeguard human health by regulating any future or ongoing emission of these substances into the environment. Four aims have been identified for the National Nutrition Survey aspect of the Organochlorines Programme. · To measure baseline levels of dioxins, PCBs and organochlorine pesticides in serum sampled from the New Zealand population. · To determine the relationships of organochlorine contaminant body burden to key demographic criteria. · To investigate any evidence of increased exposure to organochlorine chemicals for specific subpopulations. · To obtain data that can be used, under the Resource Management Act 1991, to develop national environmental standards and guidelines for the protection of human health and the environment from organochlorine chemicals. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 27
A number of smaller studies on organochlorines have been carried out in New Zealand in the past and these have suggested that the body burden for the general population is in the low to medium range compared with levels found in comparable studies in Europe and North America. The present study is the largest of its type that has been undertaken in New Zealand and will obtain for the first time a detailed data set on body burden levels on a representative sample of the New Zealand population. This will allow the significance of human body burdens for New Zealanders to be assessed in the light of overseas research on the human health effects of dioxins and other organochlorines. Development of the study design involved the Epidemiology Group; Institute of Environmental Science and Research (ESR): Communicable Disease Centre, PO Box 50-348, Porirua. There are a limited number of laboratories in the world which have the capability and expertise to analyse human blood for dioxins. The two laboratories that were involved in the analytical work for this study are ESR, Lower Hutt, New Zealand and the Centers for Disease Control and Prevention, Atlanta, Georgia, USA. Because of the very low levels at which organochlorines can be present in blood and the cost involved in undertaking dioxin and organochlorine analyses, pooling of the individual samples was required. The study design proposed that analytical samples be obtained from the pooling of serum according to strata defined by key demographic, biographic and geographic parameters. Five computer-assisted questions were included in this section to help pool the Ministry for the Environment blood samples correctly. These questions were interviewer administered and show cards were used to help participants with categories for answers. Questions 1 and 2 asked how long a person had lived in an area and whether the area was a city/town or in the country. A city/town was defined as an area within 3 km of a town with at least 2,500 people. The answers to questions 1 and 2 were used to help pool the samples into strata. Questions 3, 4 and 5 asked participants if they had ever worked with, or had direct contact with, certain organochlorine chemicals. It was assumed that people who had been exposed to these chemicals would be aware of this. This information was used to group certain participants who had contact with these chemicals. The study was looking at background levels in the population and single high levels in a pooled sample would significantly distort the result. Following collection of the blood samples in the National Nutrition Survey, approximately 4­5 ml of serum was separated for each participant and stored frozen at -70 °C. Based on the questionnaire information, samples were pooled for each aspect of the study based on a protocol developed with the assistance of Statistics New Zealand. The pooled samples were then analysed using internationally accepted methods and quality assurance procedures. A printed example of the `Environmental chemicals' questions and show cards are attached as Appendix 6. BLOOD PRESSURE The NNSTAC recommended that the OMRON 706C smart-inflate blood pressure monitor be used with either a standard or large cuff. No stethoscope is required with this machine. The OMRON monitor has automatic inflation and records pulse, systolic and diastolic pressure. In the LINZ® survey, the Hawksley Random Sphygmomanometer was used. The University of Otago recommended that a small comparability study be undertaken so that the results of the National Nutrition Survey could be compared with the LINZ® survey. 28 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
The procedure was explained to all participants before the blood pressure measurements started. The participant was asked whether any blood pressure medication was taken and this was recorded. Blood pressure was measured over bare skin where possible. Participants were seated at a table, with their left arm resting on the table so that their inner elbow was level with their heart. A towel was used to adjust the height of the arm. The large cuff was used if the arm circumference was greater than 35 cm. Where the interviewer was unsure, the large cuff was used initially and changed to the small cuff if necessary. Three measurements are made on the left arm (wherever possible) with a one minute gap between each reading. When a measurement was not taken, the reason for this was recorded. ANTHROPOMETRIC MEASUREMENTS Measurements of height, weight, triceps and subscapular skinfolds, and waist and hip circumference were taken. These measurements could be used as indicators of levels of body fatness and the location of fat. The distribution of body fat was particularly important as an indicator of cardiovascular and metabolic health risks. It was recommended by the NNSTAC to measure only two skinfold sites so that comparisons could be made with previous New Zealand surveys. It was agreed by the committee that the respondent burden (both time and effort) was too great to take further skinfold measures. Elbow breadth measurement was taken and is used as an indication of frame size. Mid-upper arm circumference was taken and is used in conjunction with the triceps skinfold to calculate arm muscle and fat areas as an indicator of nutritional status. The NNSTAC recommended that the Anthropometric Standardisation Reference Manual (Lohman et al 1988) be used to standardise the collection of physical measurements. The participant was asked to remove heavy jewellery and empty their pockets before anthropometric measurements were made. In general, measurements were made by the interviewer and recorded by the assistant. If a person was chairbound or unable to stand unaided, no physical measurements were taken. If they were unable to stand upright, weight and waist and hip measurements were taken if possible. All females under 55 years of age were asked if they were pregnant. No physical measurements were taken from women who were pregnant. When a measurement was not taken, the reason for this was recorded. The assistant recorded any characteristics that may have affected the accuracy of the measurement (eg, hairstyle/headgear). The measurements were made in the following order: HEIGHT The participant was asked to remove their shoes. A portable stadiometer (designed by the University of Otago) was used on a level floor. The participant was asked to stand with their feet flat on the base plate, heels together and weight evenly distributed on both feet. The participant's back was as straight as possible, their arms hanging loosely by their sides and their heads positioned so that their line of vision was parallel to the floor. The participant was asked to breath in deeply and stretch to their fullest height, without altering their head position. The bar was brought down gently onto the participant's head with enough pressure to compress any hair. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 29
Two measurements were made (to the nearest 0.1 cm). The participant was asked to step away from the stadiometer between each measurement. If the two measurements differed by more than 0.5 cm, then the assistant requested the interviewer take a third measurement. WEIGHT Seca digital platform scales (Model 770), calibrated at every interview, were used. The scales are able to measure weights up to 200 kg. Calibration weights of 5 kg were used prior to each weighing. A masonite board was taken to each interview so that the scales could be placed on a hard level surface. The participant was asked to stand on the scales with their feet together, arms hanging loosely by their side and head facing forward. Two measurements were made (to the nearest 0.1 kg). The participant was asked to step away from the scales between each measurement. If the two measurements differed by more than 0.5 kg, the assistant instructed the interviewer to take a third measurement. Participants wearing artificial limbs were not asked to remove them. Participants who had artificial limbs but were not wearing them were not asked to put them on. Interviewers recorded these details as required. CIRCUMFERENCE MEASUREMENTS Waist and hip circumference measurements were taken over one layer of light clothing using a Rabone metal diameter tape. Mid-upper arm circumference measurements were taken on bare skin where possible. All measurements were taken with the tape in a horizontal position, pulled firmly but not causing indentation. All measurements were taken twice and recorded to the nearest 0.1 cm. The assistant instructed the interviewer to take a third measurement where the waist and/or hip measurements differed by more than 1.0 cm or the mid-upper arm measurements differed by more than 0.5 cm. The waist measurement was taken at the natural narrowing midway between the last rib and the crest of the ilium. The measurement was taken at the end of a normal expiration. The hip measurement was taken at the maximum circumference around the buttocks when viewed from the side. Participants should not have contracted their gluteal muscles. The mid-upper arm measurement was taken on the right side of the body. The participant was asked to flex their elbow to 90° with their palm facing upwards. The interviewer stood behind the participant to locate the mid point between the tip of the shoulder and the point of the elbow. The mid point was marked with a felt tip pen. The circumference measurement was taken with the participant's arm hanging just away from their side with their palm facing their thigh. ELBOW BREADTH The measurement was taken using vernier bone callipers and recorded to the nearest 0.1 cm. The interviewer measured the distance between the epicondyles of the humerus on the right arm. The interviewer stood in front of the participant as they flexed their elbow to 90° with the back of their hand facing the interviewer. The interviewer felt the position of the epicondyles and applied the callipers at a slight angle to the epicondyles rather than parallel to them. Firm pressure was exerted to decrease the influence of soft tissue. The assistant instructed the interviewer to take a third measurement where the elbow breadth measurements differed by more than 0.5 cm. 30 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
SKINFOLDS Triceps and subscapular skinfold measurements were taken using Harpenden callipers. The measurements were taken on the right side of the body where possible, with the respondent standing in the anthropometric posture, arms hanging comfortably and loosely at their side. The triceps skinfold was measured on the back of the arm at the point marked for the mid-upper arm circumference. The interviewer stood behind the participant and picked up the tricep skinfold with the thumb and index finger directed downwards, approximately 1.0 cm above the marked point. The calliper was applied to the marked point and held for four seconds before the reading was taken. The subscapular skinfold was measured on the back, just below the inferior angle of the scapular. The interviewer stood behind the participant and identified the inferior angle of the scapular by running their fingers along its border. The interviewer picked up the subscapular skinfold with the thumb and index finger on a diagonal, inclined downwards and outwards approximately 45° to the horizontal plane in line with the natural cleavage of the skin. The calliper was applied 1.0 cm below the thumb and finger and held for four seconds before the reading was taken. Two measurements for each site were taken, recorded to the nearest 0.1 mm. If the two measurements differed by more than 0.5 mm, the assistant instructed the interviewer to take a third measurement. BLOOD SAMPLES There was considerable discussion among NNSTAC members about appropriate blood analyses. Indices for iron and lipids were always considered a high priority. It was recommended by the NNSTAC that a fasting sample was not necessary. A subcommittee of the NNSTAC, which also included representatives from the University of Otago, was formed to advise further on the blood analyses. The final list of analyses to be conducted was made just prior to the survey beginning. They were: · mean cell volume · packed cell volume · haematocrit · platelets · haemoglobin · red blood cell count · white blood cell count · C-reactive protein · serum ferritin · erythrocyte protoporphyrin · HDL cholesterol · total cholesterol · transferrin receptors (females aged 15­34 years inclusive) · organochlorine chemicals. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 31
Three vacutainers of blood were collected from each respondent with minimum stasis from an arm vein. The three vacutainers were separated as follows: · 5 ml vacutainer with EDTA added Used for: mean cell volume packed cell volume haematocrit haemoglobin platelets red blood cell count white blood cell count erythrocyte protoporphyrin. Laboratory protocol precluded any storage of remaining sample. · 10 ml vacutainer Used for: HDL cholesterol total cholesterol transferrin receptors C-reactive protein serum ferritin. Up to three 0.5 ml aliquots of serum and one 0.5­1.6 ml aliquot of serum are stored at -80°C. · 10 ml vacutainer Used for: organochlorine chemicals by the Ministry for the Environment. Each vacutainer was labelled with a barcode label at the time of data collection. The blood samples were transported by courier to Southern Community Laboratories in Dunedin. Because of changes in flight schedules to Dunedin, weekend samples were transported to Southern Community Laboratories in Christchurch for haematology analyses. Frozen serum was subsequently shipped to Dunedin for the remaining assays the following week. Haematology assays are identical in the Dunedin and Christchurch laboratories. Blood samples were packaged for transport by New Zealand Couriers according to the specifications of the IATA Packing Instruction 650 in packaging supplied by Dangerous Goods Management Ltd. STORAGE OF BLOOD SAMPLES Storage of blood serum samples was seen as advantageous by the NNSTAC, as not all analyses were possible given the budget. Samples to be stored for future analysis are three 0.5 ml serum samples in separate aliquots and one serum aliquot to fill a 1.6 ml tube as much as possible were stored in a -70°C freezer. 32 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
The protocol for the collection and storage of blood was developed in consultation with the ethics committee and all involved groups. The aliquots of blood are stored at the University of Otago under the kaitiakitanga (guardianship) of Te Rцpu Rangahau Hauora a Eru Pцmare. Other researchers wanting to access these samples for nutrition-related assays will have to seek the permission of Te Rцpu Rangahau Hauora a Eru Pцmare, ethics committees and the Ministry of Health. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 33
INTERVIEW TIMES The average length of the full interview changed over the course of the survey as interviewers increased their skill with the computer programme. Also, there was wide variability in the length of the interview depending on the age of the participant, language barriers, the amount eaten and the complexity of the diet in the previous 24 hours. The interview length could also be affected by the `Your usual food intake' questionnaire. If the questionnaire had not been completed prior to the interview, or it required a lot of checking, this increased the length of the interview significantly. Bearing in mind the difficulties mentioned above, the average interview time was calculated during a four-week period of the survey to be 69 minutes, with a range from 31 minutes to 162 minutes. 34 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
ETHICAL ISSUES The National Nutrition Survey is a voluntary survey. Ethical approval for the survey was obtained from all of the regional health authorities (RHAs) after the application was placed with the Wellington RHA Ethics Committee. INFORMED CONSENT Informed consent was obtained from each participant. Two separate consent forms were used: one for participants aged 15­17 years requiring parental or guardian approval; and one for participants aged 18 years and older. These are attached as Appendix 7. FEEDBACK TO PARTICIPANTS Participants were also asked whether they wanted to receive feedback on some of their clinical results. The interviewers were not permitted to provide verbal feedback to the participants on their measurements. All results were reviewed by the clinical principal investigator and a letter was sent to the participant. Examples of the three letters are included in Appendix 8. Letter one went to participants with results in the normal range. Letter two went to participants with results that were considered significantly outside the normal range. Letter three went to participants with results that were considered outside the normal range, but of sufficient concern that the participant was directed to visit their local doctor. This letter also included the option of sending the results to the doctor. The criteria for determining if a participant received letter three was a case-by-case decision made by the clinical principal investigator. Blood haematology results were not routinely reported to participants because of their complexity of interpretation. In cases where there were unusual features to the blood haematology, the participant was asked if they wanted the results forwarded to their doctor. The participant was asked to supply the name and address of their doctor so that this could be done. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 35
PROMOTIONAL MATERIALS To ensure that informed consent was achieved, an information pamphlet was given to all participants in the New Zealand Health Survey by the health survey interviewer. A copy of this pamphlet is attached as Appendix 9. A second pamphlet was designed by the Ministry of Health to inform health professionals about the New Zealand Health Survey and the National Nutrition Survey. This is attached as Appendix 10. A change of address card was given to all New Zealand Health Survey participants by the health survey interviewer. This was a useful method of keeping track of changes of addresses, phone numbers or unavailability for periods of time. A copy of the card is attached as Appendix 11. A calling card was carried by all National Nutrition Survey interviewers to leave at the participant's house if they were not home. A copy of the card is attached as Appendix 12. A pencil was included with the `Your usual food intake' questionnaire posted to each National Nutrition Survey participant. This was used to fill in the optically-scanned questionnaire. The pencil also had the National Nutrition Survey toll-free phone information number. A toll-free telephone line was set up to provide a contact point for participants who wanted to ask the University of Otago questions about the National Nutrition Survey. 36 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
ACKNOWLEDGMENTS
NON-MINISTRY MEMBERS OF THE NATIONAL NUTRITION SURVEY TECHNICAL ADVISORY COMMITTEE
Name
Position
Time on committee
Professor Jim Mann (Chair)
Professor of Human Nutrition, University of Otago.
Aug '95 ­
Dr Barry Borman
Central Regional Health Authority.
Nov '96 ­
Professor Rosalind Gibson
Professor of Human Nutrition, University of Otago.
Mar '96 ­
Dr Hunaara Kaa Judith Ka'ai
University of Auckland. Te Hotu Manawa Mдori.
Feb '96 ­ Mar '96 Mar '96 ­
Makuini McKerchar
Southern Health Ltd.
Feb '96 ­
Winsome Parnell
Department of Human Nutrition, University of Otago.
Aug '95 ­ Aug '96
Life in New Zealand Health and Activity Research Unit Observer, University of Otago.
Aug '96 ­
Dr Robert Scragg
Department of Community Health, University of Auckland.
Aug '95 ­
Susan Sharpe
Department of Medicine, University of Auckland.
Aug '95 ­ May '96
Dr Murray Skeaff
Department of Human Nutrition, University of Otago.
Aug '95 ­
Dr Boyd Swinburn
National Heart Foundation.
July '96 ­
Patsy Watson
Department of Chemistry, Massey University (Albany Campus).
Aug '95 ­
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 37
MINISTRY OF HEALTH MEMBERS OF THE NATIONAL NUTRITION SURVEY TECHNICAL ADVISORY COMMITTEE
Name
Position
Time on committee
Dr Gillian Durham
Director of Public Health and General Manager, Public Health Group
Aug '95 ­
Elizabeth Aitken
Senior Advisor, Nutrition
Aug '95 ­
Donnell Alexander
Advisor, Nutrition
Aug '95 ­ Mar '96
Maraea Bellamy
Team Leader-Sector, Te Kete Hauora
Nov '95 ­ Feb '96
Mark Clements
Advisor, Medical Statistician
Aug '95 ­
Lib Coubrough
Advisor, Nutrition
Feb '96 ­ May '97
Jill Coulson
Senior Advisor, Epidemiology
Nov '95 ­ Feb '96
Michele Grigg
Senior Advisor, Demography
Aug '95 ­ May '97
Jane McLennan
Advisor, Nutrition
July '96 ­
Dr Arbutus Mitikulena
Public Health Medicine Registrar
Nov '95 ­ Feb '96
Gail Powell
Acting Manager, Public Health Intelligence
May '96 ­ Sep '96
Robert Quigley
Coordinator, National Nutrition Survey
Nov '95 ­
Jenny Reid
Senior Advisor, Nutrition
Aug '95 ­ Jan '96 Feb '97 ­
Tim Rochford
Advisor, Mдori Public Health Policy
Nov '95 ­ May '97
Michelle Vanderlanh Smith Senior Advisor, Pacific People's Health Nov '95 ­ May '97
Carolyn Watts
Advisor, Nutrition
Mar '96 ­
Heather Wilson
Advisor, Nutrition
Feb '96 ­
Helen Wyn
Manager, Public Health Intelligence
Nov `95 ­
38 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
INDEPENDENT EXPERTS INVOLVED IN THE SELECTION PROCESS
Name Barbara Brown Professor Stewart Truswell Hiki Pihema Makuini McKerchar Judy Paulin
Position Commonwealth Department of Health and Family Services, Australia. Professor of Human Nutrition, University of Sydney, Australia. Te Taro O Te Ora, Gisborne. Southern Health Ltd. Department of Justice.
THE UNIVERSITY OF OTAGO The University of Otago was the provider of the National Nutrition Survey to the Ministry of Health. The Life in New Zealand Health and Activity Research Unit coordinated the project providing the organisation and overall management on behalf of the University of Otago. The main groups involved in the National Nutrition Survey are. · The Life in New Zealand Health and Activity Research Unit, University of Otago. · The Department of Human Nutrition, University of Otago. · Te Rцpu Rangahau Hauora a Eru Pцmare, Wellington School of Medicine, University of Otago. · Southern Community Laboratories, Dunedin.
PERSONNEL
The University of Otago personnel involved in the National Nutrition Survey are:
Project Director:
Professor David Russell
Project Coordinator:
Dr Noela Wilson
Nutrition Managers:
Winsome Parnell Sarah Zino
Computer Scientist: Computer Assistant: Nutritionists: Secretary: Field Secretary:
Charles Blakey Tony O'Hagan Rachel Bolch Ianthe Jones Louise Mainville Frances Okey Michelle Hurdle
Regional Supervisors:
Wendy Slatter Amanda Tomlinson
Regional Administrator:
Birnie Allen
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 39
PRINCIPAL INVESTIGATORS
Nutrition:
Winsome Parnell Dr Caroline Horwath Dr Elaine Ferguson
Clinical Measures: Blood: Blood Pressure:
Dr Ted Nye Dr Jim Faed Dr Rob Walker
Anthropometry: Mдori: Pacific:
Dr Barry Wilson Dr Papaarangi Reid Dr Colin Tukuitonga
Biostatistician:
Peter Herbison
C O N S U L TA N T S Nutrition: Clinical Measures: Blood: Blood Pressure: Anthropometry: Mдori: Pacific: Biostatistician:
Mrs Penny Field Professor David Skegg Professor Murray Tilyard Dr Wayne Sutherland Dr Ian Morrison Dr Murray Skeaff Dr Ted Nye Dr Michael Marfell-Jones Ms Druis Barrett Professor Mason Durie Dr Sitaleki Finau Dr Debbie Ryan Mrs Metua Faasisila Mr Henry Tuia Mr Len Cook
40 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
APPENDICES
APPENDIX 1: FOOD/NUTRIENT MATCHING FLOWCHART:
Yes Match Made ­ Document decision
Otago Is there a direct match on the NZFCD? No Otago Is it appropriate to use overseas FC data for this food item?
Yes
No
CFR
Is there a match from the
Australian FC Database?
Yes Otago & CFR
No CFR
Is the frequency-of-use high enough (relative to other foods) or does the food contribute significantly to the diet so that this can be one of the 200 foods supplied from the Australian FC database?
Is there a match from USDA, British or another Food Composition database? No
Yes
Yes
Otago
Match Made
Is the frequency of use high enough
­ Document decision
(relative to other foods) or does this food
contribute significantly to the diet to
justify NZ analysis of this food?
KEY
Otago ­ University of Otago
CFR ­ Crop & Food Research Ltd
FC ­ Food Composition
Yes
USDA ­ United States Department of Agriculture
NZFCD ­ New Zealand Food Composition Database
No Otago & CFR Choose `best fit' from FC data (preferably NZFCD) ­ Document Decision
CFR & FC Steering Committee
Is this food able to be analysed?
Yes
eg. cost, time, availability
No Otago & CFR
CFR analysis Match Made ­ Document Decision
Choose `best fit' from FC data (preferably NZFCD) ­ Document Decision
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 41
APPENDIX 2: DIETARY SUPPLEMENTS QUESTIONS
1. Did you take any vitamin and/or mineral capsules/tablets at any time during the year?
YES
NO
® Q3
DON'T KNOW ® Q3
42 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
2. What vitamins and/or minerals did you take? Use Supplement Show Card 1 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 43
Type
Brand Name
Multi/vitamins or minerals Multi/vitamins with iron Multi/vitamins with other minerals Vitamin A or carotenoids Thiamin (B1) Riboflavin (B2) Niacin (B3) Vitamin B6 Vitamin B12 B Complex Vitamins Vitamin C Vitamin D Vitamin E Anti-Oxidant Vitamin Calcium Iron Potassium Folic Acid
No. Taken
Dose
Units
Less than once a month
1-3 times per month
Frequency
Once per week
More than once per week
Daily
Episodic
Don't Know
3. Did you take any vitamin and/or mineral capsules/tablets at any time during the past 24 hours?
YES
NO
® Q5
DON'T KNOW ® Q5
4. Which vitamins and/or minerals did you take? USE SUPPLEMENT SHOW CARD 1
Type
Brand Name Number Taken
Multi/vitamins or Minerals
Multi/vitamins with Iron
Multi/vitamins with other Minerals
Vitamin A or Carotenoids
Thiamin (B1)
Riboflavin (B2)
Niacin (B3)
Vitamin B6
Vitamin B12
B Complex Vitamins
Vitamin C
Vitamin D
Vitamin E
Anti Oxidant Vitamin
Calcium
Iron
Potassium
Folic Acid
Dose
Units
5. Did you take any other dietary supplements such as plain wheat bran (unprocessed bran, not `Albran' or breakfast cereal), fibre tablets, lecithin, evening primrose oil, performance enhancers, etc. at any time during the last year?
YES
NO
® Q7
DON'T KNOW ® Q7
44 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
6. Which fibre etc. supplements did you take? Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 45
Type Wheat Bran Oat Bran Wheat Germ Fibre Tablets Lecithin Garlic Kelp Herbal Supplement Codliver Oil Evening Primrose Oil Yeast Performance Enhancers
Brand Name
No. Taken
Dose
Units
Less than once a month
1-3 times per month
Frequency
Once per week
More than once per week
Daily
Episodic Don't Know
7. Did you take any other dietary supplements such as plain wheat bran (unprocessed bran, not `Albran' or breakfast cereal), fibre tablets; lecithin, evening primrose oil, performance enhancers, etc. during the past 24 hours?
YES
NO
® End
DON'T KNOW ® End
8. Which fibre supplements etc. did you take? USE SUPPLEMENT SHOW CARD 2
Type
Brand Name Number Taken
Wheat Bran Oat Bran Wheat Germ Fibre Tablets Lecithin Garlic Kelp Herbal Supplement Codliver Oil Primrose Oil Yeast Performance Enhancer
Dose
Units
46 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
SUPPLEMENT SHOW CARD 1 Examples Include: Multivitamins or Minerals Vitamin A Thiamin (B1) Riboflavin (B2) Niacin (B3) Vitamin B6 Vitamin B12 B Complex Vitamins Vitamin C Vitamin D Vitamin E Calcium Iron Potassium
SUPPLEMENT SHOW CARD 2 Examples Include: Wheat Bran Oat Bran Wheat Germ Fibre Tablets Lecithin Garlic Kelp Herbal Supplement Codliver Oil Primrose Oil Yeast Performance Enhancers
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 47
APPENDIX 3: `YOUR USUAL FOOD INTAKE' QUESTIONNAIRE The Following pages illustrate the `Your usual food intake' questionnaire. 48 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
A Quality Guaranteed Scannable Document. Printed in Australia by ScanForm NCS on © MarkScan 7662 00 01 02 03 04 05
Identification Number:
00000000000 11111111111 22222222222 33333333333 44444444444 55555555555 66666666666 77777777777 88888888888 99999999999 This survey will help us to find out about New Zealander's food patterns and assist with health promotion and health policy development. How can you help? · By telling us what YOU usually eat (not someone else in your household!) · Please fill out the form yourself. · Be accurate, but don't spend too much time on each food. · Please answer EVERY question. · If you don't know the answers to the cooking questions, please ask the person who usually cooks your food. · Answer by FILLING the OVAL that best applies to you.
INSTRUCTIONS: · Use the pencil provided · Do not use red pen or felt tip pen · Erase mistakes fully · Make no stray marks
PENCIL ONLY Please MARK LIKE THIS: NOT LIKE THIS: $
If you have any questions, please ring: 0800 78 75 74 Thank you for contributing to this important project. © Ministry of Health
c
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 49
How to answer: Please answer by filling in the oval which best describes how often you eat or drink a particular food. Please use the pencil and rubber provided. Ensure that only one oval is filled in per food item for computer scanning.
Here are some examples:
How often do you usually eat these foods?
If on average you . . .
Never
Less than once a month
1-3 times per month
Once per week
2-4 times per week
5-6 times per week
Once per day
2 or more times per day
Never eat any sort of mince dish then you would mark
Eat cooked porridge 5 times per week in the winter, but never in the summer, then you would mark
Eat fresh peaches about 3 times a week when they are in season, then you would mark
Eat onions or leeks; onions 4 times per week, but leeks only once a month, then you would mark
PAGE 2
50 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
First of all, we have some questions about your general eating habits 1. How would you describe your eating pattern? (Please mark one only) Eat a variety of all foods, including animal products Eat eggs, dairy products, fish and chicken but avoid other meats Eat eggs and dairy products but avoid all meats and fish Eat eggs but avoid dairy products, all meats and fish Eat dairy products but avoid eggs, all meats and fish Eat no animal products Other (please specify) 2. On average, how many servings of fruit (fresh, frozen, canned or stewed) do you eat per day? Do not include fruit juice or dried fruit. (Please mark one only) (a `serving' = 1 medium piece or 2 small pieces of fruit or 1/2 cup of stewed fruit) e.g. 1 apple + 2 small apricots = 2 servings Per Day I don't eat fruit Less than 1 per day 1 serving 2 servings 3 or more servings 3. On average, how many servings of vegetables (fresh, frozen, canned) do you eat a day? Do not include vegetable juices. (Please mark one only) (a `serving' = 1 medium potato/kumara or 1/2 cup cooked vegetables or 1 cup of salad vegetables) e.g. 2 medium potatoes + 1/2 cup of peas = 3 servings Per Day I don't eat vegetables Less than 1 per day 1 serving 2 servings 3 servings 4 or more servings PAGE 3 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 51
4. On average, how many slices or rolls of bread (or toast) do you eat per day? Per Day I don't eat bread or toast © Go to question 6 Less than 1 per day 1-2 3-4 5-6 7 or more 5. What type(s) of bread, rolls or toast do you eat most often? (Please mark only those you usually eat.) White White ­ high fibre Wholemeal or wholegrain Other (please specify) 6. On average, how many servings of foods such as pasta, rice, muesli, porridge, or breakfast cereal do you eat per week? (Please mark one only) (a `serving' = 1 cup cooked rice/pasta or porridge or cornflakes or 1/2 cup muesli or 2 weetbix) e.g. 1 cup of rice 3 times per week + 2 weetbix 4 times a week = 7 servings per week Per WEEK I don't eat these foods Less than 4 per week 4-6 servings 7-9 servings 10-12 servings 13-15 servings 16 or more servings PAGE 4 52 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
7. Do you usually eat breakfast cereal?
No Ё If no, go to question 8 Yes Ё What breakfast cereal(s) do you have most often? (Please mark only those you usually have.)
Weetbix Cornflakes or Rice Bubbles Toasted muesli Untoasted muesli Special K All-Bran, San-Bran, Bran Flakes or Weetbix ­ `Hi-Bran'
Just Right, Light and Tasty or Good Morning Nutrigrain, Cocoa Pops or Honey Puffs Puffed Wheat or Mini-Wheats Porridge Other (please specify)
8. Do you eat meat or chicken fried or roasted in fat or oil?
No Ё If no, go to question 9 Yes Ё What type(s) of fat or oil do you use most often? (Please mark only those you usually use)
Butter Margarine Butter margarine blend Lard or dripping Olive or canola oil
Other oils e.g. sunflower, corn oil, safflower oil etc Don't know Other (please specify)
9. Do you eat vegetables fried or roasted in fat or oil?
No Ё If no, go to question 10 Yes Ё What type(s) of fat or oil do you use most often? (Please mark only those you usually use)
Butter Margarine Butter margarine blend Lard or dripping Olive or Canola oil
Other oils e.g. sunflower, corn oil, safflower oil etc Don't know Other (please specify)
PAGE 5
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 53
We would now like to ask in more detail about the foods you eat.
10. How often do you usually eat these foods or drinks?
Please fill one oval for each food or drink. Never Less 1-3 Once 2-4 5-6 Once 2 or
than times per times times per more
Dairy Foods
once a per week per
per
month month
week week
day times per day
Flavoured milk (e.g. milkshake, iced coffee)
Milk as a drink Milk on breakfast cereals
Milk added to hot beverages made with water (e.g. coffee, tea, milo)
Hot beverages made with milk (e.g. milo, cocoa, hot chocolate drinks) Cream or sour cream Ice cream Custard or dairy food
Yoghurt, plain or flavoured (including fromage frais)
Milk puddings (e.g. rice, semolina, instant) Cream cheese Cottage or ricotta cheese Mozzarella, feta, or camembert Edam or gouda cheese Colby, mild, tasty cheese Brie, blue and other specialty cheeses
11. Do you drink or use any type of milk? No Ё If no, go to question 12 Yes Ё What type(s) do you have most often? (Please mark only those you usually have) Standard, homogenised milk (blue top) Trim milk (green top) Super Trim Skim milk or low-fat powdered milk Light Blue
Whole or powdered whole milk (silver top) 'Calci-trim' 'Slim and Fit' Soy Milk Other (please specify)
PAGE 6
54 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
12. How often do you usually eat these foods?
Please fill one oval for each food. Bread and Cereal Foods
Never
Less than once a month
1-3 times per month
Once per week
2-4 times per week
5-6 times per week
Once per day
2 or more times per day
Focaccia, bagel, pita or other speciality breads Paraoa Parai (frybread) Rewena bread Doughboys or Ma-ori bread Crumpet or croissant Waffle or doughnut Fruit or iced buns Savoury or dry biscuits, crispbread, or crackers Cooked porridge Breakfast cereal (including muesli) Rice (including white or brown) Pasta eg. spaghetti, ravioli, macaroni, noodles
13. Do you use butter or margarine on bread or crackers? No Ё If no, go to question 14 Yes Ё What type(s) do you use most often? (Please mark only those you usually use)
Butter Unsalted butter Butter and margarine blend Low salt margarine
'Miracle', 'Sunflower' etc. (ie Polyunsaturated margarines) Reduced fat margarine e.g. 'Slimarine' 'Praise' or 'Olivo' margarine Other (please specify)
14. Do you eat pork, beef, mutton, hogget or lamb? No Ё If no, go to question 15 Yes Ё Do you trim any excess fat off these meats? (Please mark one only)
Always Often
Occasionally Never cut the fat off meat
PAGE 7
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 55
15. Do you eat chicken? No Ё If no, go to question 16 Yes Ё Do you remove the skin from chicken? (Please mark one only)
Always Often
Occasionally Never remove the skin from chicken
16. How often do you usually eat these foods?
Please fill one oval for each food. Meat and Fish
Never
Less than once a month
1-3 times per month
Once per week
2-4 times per week
5-6 times per week
Once per day
2 or more times per day
Beef mince dishes (e.g. rissoles, meatloaf)
Beef or veal mixed dishes (e.g. casserole, stir-fry)
Beef or veal ­ roast, chop, steak, schnitzel
Corned beef (including canned) or brisket
Hogget or mutton mixed dishes (e.g. stews) Hogget or mutton ­ roast, chops
Lamb mixed dishes (e.g. casserole, stir-fry) Lamb ­ roast, chop, steak
Pork mixed dishes (e.g. casserole, stir-fry) Pork - roast, chop, steak Pork - boiled bones Sausage, frankfurter or saveloy Bacon or ham Luncheon meats, salami or brawn Liver (including pate) Other offal (e.g. kidneys)
Chicken mixed dishes (e.g. casserole, stir-fry) Chicken ­ roast, fried, steamed, BBQ Turkey or duck Venison
PAGE 8
56 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
16. (Cont. . .) How often do you usually eat these foods?
Please fill one oval for each food. Meat and Fish
Never
Less than once a month
1-3 times per month
Once per week
2-4 times per week
5-6 times per week
Once per day
2 or more times per day
Mutton bird Canned tuna, salmon, sardines Eel Fish, battered Fish, fried (including fish fingers or fish cakes) Fish, steamed, baked, grilled or raw Shellfish (e.g. mussels, oysters, paua, kina, pipis) Other seafood (e.g. prawns)
17. Do you eat eggs? No Ё If no, go to question 18 Yes Ё Not counting eggs used in baking cakes etc, how many eggs do you usually eat per week? (Please mark one only)
Per WEEK Less than 1 1 egg
2 eggs 3 eggs
4 eggs 5 or more eggs per week
18. How often do you usually eat these foods?
Please fill one oval for each food. Miscellaneous Cakes, scones or pikelets Muffins - all types Sweet pies or sweet pastries Other puddings or desserts (not including milk-based puddings) Plain sweet biscuits Cream filled and/or chocolate biscuits Canned or packet soup (in winter) Home-made soup (in winter)
Never
Less than once a month
1-3 times per month
Once per week
2-4 times per week
5-6 times per week
Once per day
2 or more times per day
PAGE 9
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 57
18. (Cont. . .) How often do you usually eat these foods?
Please fill one oval for each food. Miscellaneous
Never
Less than once a month
1-3 times per month
Once per week
2-4 times per week
5-6 times per week
Once per day
2 or more times per day
Hamburger Meat pie, sausage roll or other savoury pastries Pizza Muesli bars Chocolate (including chocolate bars e.g. Moro bars) Other confectionery Jam, honey, marmalade or syrup Peanut butter, other nut spreads Vegemite or marmite Nuts Potato crisps, corn chips, Twisties etc.
19. How often do you usually eat these foods?
Please fill one oval for each food. Dressings and Sauces Mayonnaise Low-calorie salad dressing Salad dressing Tomato sauce Gravy White sauce/cheese sauce etc. Coconut cream
Never
Less than once a month
1-3 times per month
Once per week
2-4 times per week
5-6 times per week
Once per day
2 or more times per day
PAGE 10
58 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
20. How often do you usually eat these foods? (If your intake varies with season, how often do you usually have them when in season?)
Please fill one oval for each food.
Never Less 1-3 Once 2-4
5-6 Once 2 or
Vegetables
than times per times times
once a per week per
per
per more day times
(including fresh, frozen or canned)
month month
week week
per day
Potato; boiled, mashed, baked or roasted
Hot potato chips or kumara chips/ french fries/wedges Pumpkin; boiled, roast or mashed Kumara; boiled, roast or mashed Peas Mixed frozen vegetables Green beans Silver beet, spinach Carrots Cabbage, coleslaw Sweet corn Mushrooms Tomatoes Beetroot Taro Taro leaf (e.g. palusami) Green bananas Watercress Puha Sprouts (e.g. alfalfa, mung) Turnips or swedes
PAGE 11 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 59
20. (Cont. . .) How often do you usually eat these foods? (If your intake varies with season, how often do you usually have them when in season?)
Please fill one oval for each food.
Never Less 1-3 Once 2-4
5-6 Once 2 or
Vegetables
than times per times times per more
once a per week per
per
day times
(including fresh, frozen or canned)
month month
week week
per day
Parsnip
Karengo (seaweed)
Onions or leeks
Soybeans, tofu
Beans (including baked beans), lentils
Cauliflower
Broccoli or broccoflower
Brussel sprouts
Courgette/zucchini, marrow, eggplant, squash
Kamo kamo
Pacific Island yams
Yams
Capsicum (or peppers)
Celery
Cassava
Asparagus
Breadfruit
Cucumber
Avocado
Lettuce
Other green leafy vegetables e.g. Whitloof etc.
PAGE 12 60 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
21. How often do you usually eat these foods?
Please fill one oval for each food. Fresh Fruits ­ when they are in season
Never
Less than once a month
1-3 times per month
Once per week
2-4 times per week
5-6 times per week
Once per day
2 or more times per day
Apple Pear Banana Orange, mandarin or tangelo Grapefruit Peach, nectarine, plum or apricot Mango, paw-paw or persimmons Pineapple Grapes Strawberries and other berries or cherries Melon (e.g. watermelon, rockmelon etc.) Kiwifruit Feijoas Tamarillos
22. How often do you usually eat these foods?
Please fill one oval for each food. Other Fruits
Never
Less than once a month
1-3 times per month
Once per week
2-4 times per week
5-6 times per week
Once per day
2 or more times per day
Sultanas, raisins or currants Other dried fruit (e.g. apricots, prunes, dates) Preserved or canned fruit in syrup Preserved or canned fruit in water or juice Stewed fruit
PAGE 13
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 61
Well done, just one more question!
(Please note that the possible categories you have to choose from have changed.)
23. How often do you usually have these drinks?
Please fill one oval for each drink. Drinks
Never or rarely
3 times a month or less
1-2 times per week
3-6 times per week
1-2 times per day
3-5 times per day
6 or more times per day
Fruit juice e.g. Just Juice, Fresh-up, Robinson's or Rio Gold etc. Vegetable juice (e.g. tomato juice) Fruit drink e.g. Choice, Rio Splice etc. Powdered drinks (e.g. Raro, Vita-fresh etc.) Low-calorie cordial Cordial Diet carbonated drink (e.g. diet sprite) Carbonated drinks (e.g. coke, lemonade etc.) Sport's drinks (e.g. Gatorade, Powerade etc.)
Water (including unflavoured mineral water, soda water, tap water) Coffee Coffee ­ decaffeinated Coffee substitute (e.g. Inka) Koko Tea Herbal tea Soy beverages Beer ­ low alcohol Beer ­ ordinary Red wine White wine or champagne / sparkling wine Wine cooler Sparkling grape juice Sherry or port Spirits, liqueurs
PAGE 14
62 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
Are there any other foods, not included in this questionnaire, that you eat at least once a week? If so, please tell us:
Who completed this questionnaire? Myself Interviewer Someone else
Today's date is:
19
DATE JAN 1996 FEB 1997 0 0 MAR 1998 1 1 APR 1999 2 2 MAY 2000 3 3 JUN 2001 4 JUL 2002 5 AUG 2003 6 SEP 2004 7 OCT 2005 8 NOV 2006 9 DEC 2007
Thank you for your time and effort in completing this questionnaire. It is much appreciated. PAGE 15
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 63
APPENDIX 4: BARRIERS TO DIETARY CHANGE QUESTIONS INTERVIEWER TO COMPLETE:
1. Servings of fruit per day? See Q2 in QFFQ
number
2. Servings of vegetables per day? See Q3 in QFFQ
number
3. Servings of bread per day? See Q4 in QFFQ
number
Servings of cereals per week? See Q6 in QFFQ
number
(Totals per day
number)
4. I'd now like to ask you some questions about changes to your choice of foods.
Are you trying at present to make any changes to your choice of foods?
(For example, trying to change the amounts or types of foods you eat)
Yes
® Q5
No
® Q10
Don't Know
® Q10
64 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
5. We'd now like you to think about four particular groups of foods.
For each group of foods, can you tell me if you are trying at present to change the amount you eat?
(Interviewer to show each card in turn then note all positive responses that apply)
DIETARY CHANGE SHOW CARD 1
fruits
DIETARY CHANGE SHOW CARD 2
vegetables
DIETARY CHANGE SHOW CARD 3
breads and cereals
DIETARY CHANGE SHOW CARD 4
butter, margarine, oils, and other foods high in fat
fruits
® Q6
vegetables
® Q7
breads or cereals
® Q8
butter, margarine, oils and other foods high in fat ® Q9
IF NONE OF THESE
® Q10
Comments
If in answering Q5, the subject has already described whether they are trying to eat more or less of the food group, simply record the answer below rather than asking Q6-9 unnecessarily. 6. About fruit, in what way are you trying to change? (ask as open-ended question). USE DIETARY CHANGE SHOW CARD 5 more less don't know If respondent indicates a change in fruit only ® Q10 7. About vegetables, in what way are you trying to change? (ask as open-ended question). USE DIETARY CHANGE SHOW CARD 5 more less don't know If respondent indicates a change in fruit and/or vegetables only ® Q10 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 65
8. About bread or cereals, in what way are you trying to change? (ask as open-ended question). USE DIETARY CHANGE SHOW CARD 5 more less don't know If respondent indicates a change in fruit and/or vegetables and/or bread and cereals only ® Q10. 9. About butter, margarine, oils or other foods high in fat, in what way are you trying to change your choice of foods? (ask as open-ended question; note: subject to answer both questions). USE DIETARY CHANGE SHOW CARD 6 9a Eat more foods high in fat Eat less foods high in fat No change in amount eaten 9b Change type of butter, margarine or oils used No change in type eaten Comments If the respondent is presently changing a food group, then you are unable to ask about an intending change to that food group. 66 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
10. In the last question, we asked about any changes you are making now. We'd now like to ask about whether you are thinking about making any changes to the foods you eat in the future. We're interested in whether you intend or plan to make any changes over the next 6 months. Are you intending to change the amount you eat of any of these groups of foods? (Interviewer to show each card in turn, then note all positive responses)
(DO NOT ASK, SHOW SHOW CARDS 1-4)
DIETARY CHANGE SHOW CARD 1 DIETARY CHANGE SHOW CARD 2 DIETARY CHANGE SHOW CARD 3 DIETARY CHANGE SHOW CARD 4
fruits vegetables breads and cereals butter, margarine, oils, and other foods high in fat
Tick all that apply: fruits
® Q11
vegetables
® Q12
breads or cereals
® Q12
foods such as butter, margarine, oils and other foods high in fat ® Q14
IF NONE OF THESE
® Q15
Comments
___________________________________________________________________________ If in answering Q10, the subject has already described whether they are intending to eat more or less of the food group, simply record the answer below rather than asking Q11-14 unnecessarily 11. About fruit, in what way are you intending to change? (ask as open-ended question). USE DIETARY CHANGE SHOW CARD 5 more less don't know If respondent indicates that they are intending to change fruit only ® Q15. Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 67
12. About vegetables, in what way are you intending to change? (ask as open-ended question). USE DIETARY CHANGE SHOW CARD 5 more less don't know If respondent indicates that they are intending to change fruit and/or vegetables only ® Q15. 13. About bread or cereals, in what way are you intending to change? (ask as open-ended question). USE DIETARY CHANGE SHOW CARD 5 more less don't know If respondent indicates that they are intending to change fruit and/or vegetables and/or breads and cereals only ® Q15. 14. About butter, margarine, oils or other foods high in fat, in what way are you intending to change your choice of foods? (ask as open-ended question; note: subject to answer both questions). USE DIETARY CHANGE SHOW CARD 6 14a Eat more foods high in fat Eat less foods high in fat No change in amount eaten 14b Change type of butter, margarine or oils needed No change in type eaten Comments 68 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
15. If Q1 < 2 OR Q6 = `eat more fruit' (ask this question). People often find it hard to increase the amount of fruit they eat. We're interested in the sorts of things that people find most difficult about making this change. Here is a list of things that people have found difficult about eating more fruit. Would any apply to you? USE DIETARY CHANGE SHOW CARD 7 FRUIT Cost too much I don't like fruit Can't store fruit for long It's a hassle to try and eat more Often of poor quality Fruit causes stomach upsets or indigestion It's hard to chew Causes allergy or other bad reaction Not enough time Don't always have fruit at home Contains too much sugar Fruit is not good for me Would need willpower to eat more Pesticides or chemicals on fruit I would not find it hard to eat more Other (describe) ® Q16 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 69
16. If Q2 < 3 OR Q7 = `eat more vegetables' (ask this question). People often find it hard to increase the amount of vegetables they eat. We're interested in the sorts of things that people find most difficult about making this change. Here is a list of things that people have found difficult about eating more vegetables. Would any apply to you? USE DIETARY CHANGE SHOW CARD 8 VEGETABLES Cost too much I don't like vegetables Can't store them for long It's a hassle to try and eat more Often of poor quality They cause stomach upsets or indigestion Vegetables are hard to chew Causes allergy or other bad reaction Take too long to prepare Don't always have them at home It's hard to prepare vegetables I have nowhere to cook vegetables Not enough time Would need willpower to eat more They're not good for me Pesticides or chemicals on vegetables I would not find it hard to eat more Other (describe) ® Q17 70 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
17. If Q3 < 6 (total) OR Q8 = `eat more breads or cereals' (ask this question). People often find it hard to increase the amount of breads and cereals they eat (Use DIETARY CHANGE SHOW CARD 3 to remind them of foods in this group). We're interested in the sorts of things that people find most difficult about making this change. Here is a list of things that people have found difficult about eating more breads and cereals. Would any apply to you? USE DIETARY CHANGE SHOW CARD 9 BREADS AND CEREAL FOODS Cost too much I don't like them They're fattening It's a hassle to try and eat more They're too filling They upset my stomach They're too heavy They provide too many calories They're too starchy They're not good for me They cause wind Would need willpower to eat more I would not find it hard to eat more Other (describe) ® Q18 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 71
18. ALL subjects to answer: People often find it hard to cut down the amount of butter, margarine, oils or other foods high in fat. We're interested in the sorts of things that people find most difficult about making this change. Here is a list of things that people have found difficult about cutting down on butter, margarine, oils or other foods high in fat. Would any apply to you? USE DIETARY CHANGE SHOW CARD 10 BUTTER, MARGARINE, OILS OR OTHER FOODS HIGH IN FAT They taste good It's hard to prepare meals with less fat They're convenient There are few low-fat alternatives Cheap The people I live with would have to eat less too Would need willpower It's hard when I eat out a lot My body needs fat Preparing meals with less fat takes too long I like to eat these foods for comfort It's a hassle to try and eat less I wouldn't enjoy food as much None of the above, I'm happy with my fat intake Other (describe) End Barriers Questions 72 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
DIETARY CHANGE SHOW CARD 1 FRUITS Also includes: coconut pawpaw watermelon figs mango guava
DIETARY CHANGE SHOW CARD 4 Butter, margarine, oils, and OTHER FOODS HIGH IN FAT For example: FRIED FOOD AND PASTRIES DIETARY CHANGE SHOW CARD 5 EAT MORE EAT LESS
DIETARY CHANGE SHOW CARD 2 V E G E TA B L E S Also includes: manioc/cassava taro kumara puha green bananas choko DIETARY CHANGE SHOW CARD 3 BREADS AND CEREALS Also includes: breakfast cereals porridge muesli rice pasta
DIETARY CHANGE SHOW CARD 6 FOODS HIGH IN FAT AMOUNT EATING MORE EATING LESS EATING THE SAME TYPE OF BUTTER, MARGARINE OR OILS CHANGED THE TYPE HAVEN'T CHANGED
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 73
DIETARY CHANGE SHOW CARD 7 FRUIT Cost too much I don't like fruit Can't store fruit for long It's a hassle to try and eat more Often of poor quality Fruit causes stomach upsets or indigestion It's hard to chew Causes allergy or other bad reaction Not enough time Don't always have fruit at home Contains too much sugar Fruit is not good for me Would need willpower to eat more Pesticides or chemicals on fruit I would not find it hard to eat more Other
DIETARY CHANGE SHOW CARD 8 VEGETABLES Cost too much I don't like vegetables Can't store them for long It's a hassle to try and eat more Often of poor quality They cause stomach upsets or indigestion Vegetables are hard to chew Causes allergy or other bad reaction Vegetables take too long to prepare Don't always have them at home It's hard to prepare vegetables I have nowhere to cook vegetables Not enough time Would need willpower to eat more They're not good for me Pesticides and chemicals on vegetables I would not find it hard to eat more Other
74 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
DIETARY CHANGE SHOW CARD 9 BREAD AND CEREALS Cost too much I don't like them They're fattening It's a hassle to try and eat more They're too filling They upset my stomach They're too heavy They provide too many calories They're too starchy They're not good for me They cause wind Would need willpower to eat more I would not find it hard to eat more Other
DIETARY CHANGE SHOW CARD 10 BUTTER, MARGARINE, OILS OR OTHER FOODS HIGH IN FAT Taste good It's hard to prepare meals with less fat They're convenient There are few low-fat alternatives Cheap The people I live with would have to eat less too Would need willpower It's hard when I eat out a lot My body needs fat Preparing meals with less fat takes too long I like to eat these foods for comfort It's a hassle to try and eat less I wouldn't enjoy food as much None of the above, I'm happy with my fat intake Other
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 75
APPENDIX 5: FOOD SECURITY QUESTIONS INTRODUCTION I now want to ask you some questions about particular foods you choose, and the buying of food or gifting of food. We are interested in whether you feel you always have sufficient resources to have the food you need for yourself and the people you live with. We are not concerned with your budget, or how you spend your money, but we are more interested in finding out about how people get the food that they need for their household to eat and share. (In all questions `we' refers to the household, unless it is a one-person household). First of all, we know that some people can't afford to eat properly and we are interested in whether you think you eat properly. It's what you think eating properly is - not what I or anyone else thinks. USE FOOD SECURITY SHOW CARD 1 I / WE CAN AFFORD TO EAT PROPERLY Always Sometimes Never Don't Know 2. We are interested in whether you run out of basics, like bread, potatoes, etc. because you do not have enough money. We are NOT referring to treats or special foods. USE FOOD SECURITY SHOW CARD 2 FOOD RUNS OUT IN MY / OUR HOUSEHOLD DUE TO LACK OF MONEY How often has this been true for you (or your household) over the past year? Often Sometimes Never Don't Know 76 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
3. Now we are interested in whether a lack of money leads you to sometimes have smaller meals than you would like or whether a lack of money means there isn't enough for seconds or you sometimes skip meals? USE FOOD SECURITY SHOW CARD 3 I / WE EAT LESS BECAUSE OF LACK OF MONEY How often has this been true for you (or your household) over the past year? Often Sometimes Never Don't Know 4. Now we are going to talk about the variety of foods you eat. By variety we mean the number of different kinds of foods you have. USE FOOD SECURITY SHOW CARD 4 THE VARIETY OF FOODS I AM (WE ARE) ABLE TO EAT IS LIMITED BY A LACK OF MONEY How often has this been true for you (or your household) over the past year? Often Sometimes Never Don't Know 5. Some people rely on support and assistance from others for supplying their regular food and we are interested in find out how many people fall into this group. USE FOOD SECURITY SHOW CARD 5 I / WE RELY ON OTHERS TO PROVIDE FOOD AND/OR MONEY FOR FOOD, FOR MY / OUR HOUSEHOLD, WHEN I / WE DON'T HAVE ENOUGH MONEY How often has this been true for you (or your household) over the past year? Often Sometimes Never Don't Know Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 77
6. Also, some people have to rely on other sources of help such as food grants or food banks. USE FOOD SECURITY SHOW CARD 6 I / WE MAKE USE OF SPECIAL FOOD GRANTS OR FOOD BANKS WHEN I / WE DO NOT HAVE ENOUGH MONEY FOR FOOD How often has this been true for you (or your household) over the past year? Often Sometimes Never Don't Know 7. We know that some people get quite stressed and worried about providing enough food even though they don't actually go without food. USE FOOD SECURITY SHOW CARD 7 I FEEL STRESSED BECAUSE OF NOT HAVING ENOUGH MONEY FOR FOOD How often has this been true for you (or your household) over the past year? Often Sometimes Never Don't Know 8. We recognise that for some people food and sharing food with others is important, to the point that they won't have enough food for themselves. In this question we are only interested in social situations which are gatherings within, or outside, the household. As a result people may find themselves stressed/whakama (embarrassed) about their koha (gift) when providing food for others. USE FOOD SECURITY SHOW CARD 8 I FEEL STRESSED BECAUSE I CAN'T PROVIDE THE FOOD I WANT FOR SOCIAL OCCASIONS How often has this been true for you (or your household) over the past year? Often Sometimes Never Don't Know 78 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
FOOD SECURITY SHOW CARD 1
FOOD SECURITY SHOW CARD 5
I / WE CAN AFFORD TO EAT PROPERLY Always Sometimes Never Don't Know FOOD SECURITY SHOW CARD 2 FOOD RUNS OUT IN MY / OUR HOUSEHOLD DUE TO LACK OF MONEY Often Sometimes Never Don't Know FOOD SECURITY SHOW CARD 3 I / WE EAT LESS BECAUSE OF LACK OF MONEY
I / WE RELY ON OTHERS TO PROVIDE FOOD AND/OR MONEY FOR FOOD FOR MY / OUR HOUSEHOLD, WHEN I / WE DON'T HAVE ENOUGH MONEY Often Sometimes Never Don't Know FOOD SECURITY SHOW CARD 6 I / WE MAKE USE OF SPECIAL FOOD GRANTS OR FOOD BANKS WHEN I / WE DO NOT HAVE ENOUGH MONEY FOR FOOD Often Sometimes Never Don't Know
Often Sometimes Never Don't Know FOOD SECURITY SHOW CARD 4 THE VARIETY OF FOOD I AM (WE ARE) ABLE TO EAT IS LIMITED BY A LACK OF MONEY Often Sometimes Never Don't Know
FOOD SECURITY SHOW CARD 7 I FEEL STRESSED BECAUSE OF NOT HAVING ENOUGH MONEY FOR FOOD Often Sometimes Never Don't Know FOOD SECURITY SHOW CARD 8 I FEEL STRESSED BECAUSE I CAN'T PROVIDE THE FOOD I WANT FOR SOCIAL OCCASIONS Often Sometimes Never Don't Know
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 79
APPENDIX 6: ENVIRONMENTAL CHEMICALS QUESTIONS
I am now going to ask you some questions about your exposure to chemicals during your lifetime: 1. USE CHEMICALS SHOW CARD 1
How long have you lived in this area?
Less than one year
6 - 10 years
1- 5 years
10 + years
Don't Know
2. USE CHEMICALS SHOW CARD 2 Throughout your life have you lived mainly in the:
country
not sure
city or town
We are interested in whether you have ever worked or had direct physical contact with three types of chemicals: 3. First, pentachlorophenol which was a chemical used for antisapstain treatment in the timber industry. Have you ever worked or had direct physical contact with pentachlorophenol?
yes
no
don't know
Comment
80 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
Second, polychlorinated biphenyls, which are known as PCBs and were widely used in electrical transformers and capacitors. 4. Have you ever manufactured or repaired electrical transformers or capacitors?
yes
no
don't know
Comment
Third, organochlorine pesticides, which are chemicals used to kill insects and other pests. 5. USE CHEMICALS SHOW CARD 3
Have you ever worked with or had direct physical contact with any of the organochlorine pesticides shown on this card?
yes
no
don't know
Comment CHEMICALS SHOW CARD 1 Less than one year 1-5 years 6-10 years 10 + years CHEMICALS SHOW CARD 2 Country City or town Not sure
CHEMICALS SHOW CARD 3 ORGANOCHLORINE PESTICIDES DDT Dieldrin Aldrin Lindane HCB Heptachlor Chlordane
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 81
APPENDIX 7: CONSENT FORMS
NATIONAL NUTRITION SURVEY TEENAGERS (15-17 YEARS)
A National Nutrition Survey is planned and will be conducted throughout New Zealand by the University of Otago on behalf of the Ministry of Health, Ministry for the Environment and the Regional Health Authorities. This study involves about 5,000 New Zealanders and will take place over a 12-month period starting December 1996. The survey involves being interviewed about the food you have eaten recently and completing a questionnaire about how often you eat particular foods. In addition you will complete the following: 1. Blood pressure measurement. 2. Measuring your height, weight, two skinfolds, elbow width, and hip, waist and arm girths. 3. Having a blood sample taken to be analysed for standard nutrition-related tests, such as iron and fat levels, and for environmental chemicals. The results of the national survey will be used to influence health policies with the intention of improving the nutrition of New Zealanders. Participation in this study is entirely voluntary and will in no way affect your health care. · I have been assured that my results will remain confidential and that no identifiable information about me will be revealed in any written or verbal reports about the survey. · I understand that this study has been approved by the Ethics Committees throughout New Zealand and if I have any concerns about the study, I may contact my local ethics committee. · I have read and had explained to me the information about this study. My questions have been answered to my satisfaction. I understand that I am able to stop taking part in this study at any time.
I AGREE TO TAKE PART IN THIS STUDY Signed: Participant's name: Signed: Witness name:
(participant) / / (date) (print name) (witness) / / (date) (print name) Please turn over
82 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
I AGREE TO MY CHILD'S PARTICIPATION IN THIS STUDY
Signed: Parent/Guardian name: Signed:
(parent/guardian) / / (date) (print name) (witness) / / (date)
Witness name:
(print name)
Participants may wish to receive their results. PLEASE SIGN BESIDE THE OPTION YOU WISH TO TAKE: Please send my results to me Please do not send my results to me
8 November, 1996
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 83
CONSENT FORM NATIONAL NUTRITION SURVEY ADULTS (18+ YEARS)
A National Nutrition Survey is planned and will be conducted throughout New Zealand by the University of Otago on behalf of the Ministry of Health, Ministry for the Environment and the Regional Health Authorities. This study involves about 5,000 New Zealanders and will take place over a 12-month period starting December 1996. The survey involves being interviewed about the food you have eaten recently and completing a questionnaire about how often you eat particular foods. In addition you will complete the following: 1. Blood pressure measurement. 2. Measuring your height, weight, two skinfolds, elbow width, and hip, waist and arm girths. 3. Having a blood sample taken to be analysed for standard nutrition-related tests, such as iron and fat levels, and for environmental chemicals. The results of the national survey will be used to influence health policies with the intention of improving the nutrition of New Zealanders. Participation in this study is entirely voluntary and will in no way affect your health care. · I have been assured that my results will remain confidential and that no identifiable information about me will be revealed in any written or verbal reports about the survey. · I understand that this study has been approved by the Ethics Committees throughout New Zealand and if I have any concerns about the study, I may contact my local ethics committee. · I have read and had explained to me the information about this study. My questions have been answered to my satisfaction. I understand that I am able to stop taking part in this study at any time.
I AGREE TO TAKE PART IN THIS STUDY Signed: Participant's name: Signed: Witness name:
(participant) / / (date) (print name) (witness) / / (date) (print name)
Participants may wish to receive their results. PLEASE SIGN BESIDE THE OPTION YOU WISH TO TAKE: Please send my results to me Please do not send my results to me 8 November, 1996 84 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
APPENDIX 8: PARTICIPANT FEEDBACK LETTERS LIFE IN NEW ZEALAND Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 85
LIFE IN NEW ZEALAND 86 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
LIFE IN NEW ZEALAND Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 87
Back page for previous letters 1 to 3 88 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
APPENDIX 9: PARTICIPANT INFORMATION PAMPHLET Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 89
90 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
A P P E N D I X 10 : HEALTH PROFESSIONALS INFORMATION PAMPHLET Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 91
92 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
A P P E N D I X 11 : UNIVERSITY OF OTAGO CHANGE OF ADDRESS CARD Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 93
A P P E N D I X 12 : UNIVERSITY OF OTAGO CALLING CARD 94 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
GLOSSARY
AC Nielsen packaged foods sales data.
AC Nielsen is a New Zealand company. They collect data on the packaged foods sold in New Zealand including sales volume.
Aliquot.
Measured exact amount of liquid.
Anthropometry.
The science that deals with the measurement of the size, weight and proportions of the human body. Used as indicator for various conditions related to health and nutrition.
Australian Nutrition Survey.
This survey was carried out on behalf of the Commonwealth Department of Health and Family Services by the Australian Bureau of Statistics. The Australian Nutrition Survey will provide information on the food and nutrient intakes, dietary habits and body measurements on a representative sample of Australians aged from 2 years.
Bar code.
A machine readable striped code on packaging. Used for product identification by a programmed decoder.
Barriers to dietary change.
Factors that may limit individuals in their change in food choices. They may include cultural factors, lack of knowledge, cost and time constraints.
Bioelectrical Impedance Analysis.
A method of body composition analysis based on electrical conduction.
Biographic Parameters.
Characteristics related to one person.
Body Fat Mass.
Weight of fat in the body.
Chlorinated organic chemicals (dioxins, poly-chlorinated biphenyls (PCBs) and pesticides).
Substances containing chemically combined chlorine and carbon atoms. Dioxins are produced as by-products of a number of industrial and combustion processes. Their bio-accumulation and presence in the food chain may be associated with causing cancer and hormone imbalance in humans.
Clean data set.
The final, useable data set which has been checked for errors and is ready for analyses to begin.
Coding.
Matching foods recorded during an interview to the New Zealand Food Composition Database.
Community Services Card.
A card available to certain individuals of the population which entitles subsidised health services.
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 95
Computer-assisted data capture system. Continuing Survey of Food Intakes by Individuals. Core nutrients. C-reactive protein. Crop & Food Research Ltd. Cross-sectional population survey. Cuff. Demographic Parameters. DEXA. Diet History. Dietary modelling. Dietary supplements. EDTA. Epidemiology. Erythrocyte protoporphyrin. Ethical approval.
A computer programme used to collect the responses of the participants in the National Nutrition Survey. It was developed by the University of Otago to meet the unique requirements of the National Nutrition Survey. A United States of America nationwide dietary intake survey funded by the Agriculture Research Service of the United States Department of Agriculture and carried out by Westat. The New Zealand Food Composition Database has 52 nutrients which are determined for all foods on the database. Other non-core nutrients are available for certain foods. A blood serum protein which is sensitive to acute infection. A Crown Research Institute contracted by the Ministry of Health to provide the New Zealand Food Composition Database. A survey that involves a representative sample of the people of New Zealand. A sleeve/band on the Omron blood pressure monitor that fits around the participants' arm. Characteristics related to population statistics such as age, gender and ethnicity. Dual-energy x-ray absorptiometry scanning. Used to determine body composition, including percent amounts of lean and fat tissue, and bone mineral density. A detailed dietary assessment about a participants `typical' or `usual' food intake in a 1-2 hour interview. The aim is to construct a typical seven-day eating pattern. Questions are usually open-ended and cover each meal in turn for a full seven days. Combines information about food dietary intake and/or model diets with nutrient/chemical composition of foods for risk assessment. A wide range of products that are consumed by people in the belief they will improve health and nutrition. Ethylene diamine tetra-acetic acid. An anticoagulant used for plasma blood samples to prevent blood clotting. The medical science concerned with the occurrence of disease in the community. Protoporphyrin is a precursor of haem iron found in red blood cells. It indicates gradual changes of iron supply in bone marrow and is a measure of iron deficiency. Ethical approval is granted by ethics committees after they have reviewed if the survey procedures meet all ethical standards.
96 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
Ethics committee. Five-yearly health status and the determinants reports. Food and Nutrition Guidelines for Healthy New Zealanders. Food list database. Food portion size. Food Records. Food Regulatory areas. Food Security. Geographic Parameters. Gluteal muscle. Haematocrit. Haemoglobin. Harpenden callipers. Hawksley Random Zero machine. HDL cholesterol. Household Labour Force Survey. Informed consent.
A group of community and health professional representatives who ensure that the rights of participants are upheld and participants are protected from harm. Reports that focus on trends in key social variables that impact on health status. Variables are broken down to changes in: the New Zealand population; social and physical environments; and lifestyles of New Zealanders; in relation to health outcomes. Food-based guidelines that include recommendations on the number of servings that should be consumed from each of the major food groups by healthy individuals. A database to help the interviewer identify the food that the participant has consumed. A typical amount of a particular food consumed. A method of dietary data collection where participants note the foods and drinks they consume throughout the study. An area of the government that controls aspects of the food supply through laws and restrictions. Covers such issues as hunger; stress involved with providing meals/ food; lack of money to purchase food; and lack of access to food. It deals with the key issues relating to the procurement and consumption of food for people, especially people on a low income. Characteristics related to physical aspects of the population. For example, RHA boundaries and the rural/urban split. Muscle present around the buttock area of the human body. The red blood cell fraction of blood. A measure of normality for red blood cells (otherwise known as packed-cell volume). Component of red blood cells required for oxygen transport within the body and used as a measure of frank iron deficiency anaemia. Callipers used to measure the skinfold measurements. Blood pressure machine used in the Life In New Zealand survey. High density lipoprotein cholesterol. This is seen as the `beneficial' blood cholesterol fraction because it transports cholesterol from the tissues and blood vessels back to the liver for excretion. It is desirable to have higher blood levels of this type of cholesterol in relation to other types. Survey conducted by Statistics New Zealand which collects relevant data on the labour force of New Zealand. Consent given by the participants after being told the survey details.
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 97
Institute of Environmental Science and Research Limited (ESR). Interviewer-administered questionnaire. Joint food standardsetting system. Key food habits. Lacto-ovo vegetarian. Life in New Zealand Survey. Mean Cell Volume. Minimum stasis. Ministry of Health. Modified recipe. National Plan of Action for Nutrition (NPAN). New Zealand Food Composition Database. NHANES III. Notepad.
A New Zealand Crown Research Institute contracted by the Ministry of Health to gather vitamin and mineral supplement product details. A questionnaire that is filled in by the interviewer while questioning the participant. A joint system between the New Zealand and Australian Governments exists to develop a Joint Food Standards code. The standards will cover safety, composition and labelling of foods for both countries. Significant food practices and customs which have a major impact on food and nutrient intake. An individual that eats eggs and dairy products but excludes all meats and fish. A nationwide survey of activity, nutritional status and health carried out by the University of Otago and funded by the Hillary Commission for Sport, Fitness and Leisure in 1989­1990. Measure of the average size of the red blood cell. A measure of normality for red blood cells. The smallest amount of movement of the participant, especially of the arm vein during collection of blood samples. A government department responsible for developing health policy advice to the Minister of Health. The Ministry leads the health and disability sector in promoting health through policy advice, health protection, funding management and monitoring. A recipe consumed by the participant, and the participant knows the major ingredients but not the exact amounts. A Public Health Commission 10-year strategic plan which provides advice to the Minister of Health. NPAN focuses on the policy, programmes and research issues that will help to improve health through improving food and nutrition. A database containing the nutrient composition of over 2,000 New Zealand foods. The database is maintained by the Crop & Food Research Ltd, under contract to the Ministry of Health. The third Nationwide Health and Nutrition Examination Survey. Conducted during 1988 to 1994 by the United States Department of Health and Human Services. It monitors the health and nutrition status of the United States population two months of age and older. A facility on the computer where the interviewer can record further information about foods, especially when foods could not be matched accurately to the food list database. This information is used as a later reference by the University of Otago during coding.
98 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
Optical Scanning equipment. Equipment used to machine -read the participants' responses to the `Your usual food intake' questionnaire.
Organochlorines Programme. A New Zealand programme conducted by the Ministry for the Environment to develop national environmental standards and guidelines for organochlorine substances.
Over-sampling.
The additional participants selected above and beyond those selected by random sampling. The purpose is to increase the number of Mдori and Pacific Island people participating in the National Nutrition Survey.
Packing instruction 650.
The packing procedure required to meet specifications ensuring blood samples were safe to transport around the country.
Platelets.
Blood cells that have a role in the control of bleeding.
Pooling of serum.
Individual serum blood samples mixed together to form composite samples.
Predictor Equation.
Statistical equation predicting an unknown future random variable from a known variable.
Probe questions.
Questions used by the interviewer during the multiple-pass 24-HDR to ensure that all relevant details of the foods consumed by the participant are recorded.
Producer Boards.
Elected boards that govern the primary produce of New Zealand. For example meat, dairy, fruit and vegetables.
Progress on Health Outcome Targets report.
A Ministry of Health report which monitors the progress on health outcome targets. The targets reflect public health goals and objectives.
Quartiles.
25th, 50th and 75th percentiles of a sample. Used in statistical analyses.
Rabone metal diameter tape. A measuring tool for length and circumference.
Recommended dietary intakes (RDIs).
Detailed amounts of the average daily intake of nutrients required over time to maintain good health for nearly all healthy people in New Zealand.
Red blood cell count.
The number of red blood cells per litre of blood. A measure of normality for red blood cells.
Regional health authorities (RHAs).
New Zealand has four RHAs. Each assesses the need for services in its geographic region. They purchase health and disability services for their region and monitor performance against purchase agreements.
Regression Equations.
A statistical procedure demonstrating the relation between two factors.
Repeat sample.
Approximately 10 percent of the original National Nutrition Survey participants were asked to undertake a second 24-HDR.
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 99
Respondent Burden. Sample frame. Scapular. Seca digital platform scales. Self-completed questionnaire. Serum. Serum ferritin. Show Cards. Skinfolds. Socio-demographic. Southern Community Laboratories. Stadiometer. Standard recipe. Statistics New Zealand. Stethoscope. Subsample. Subscapular. Te Rцpu Rangahau Hauora a Eru Pцmare. Therapeutic database (TDB).
The difficulty or load imposed on the participant while involved with the survey. An area-based frame from which the population sample was selected for participation in the survey. The bone that protrudes from the upper back of the human body on both sides. Commonly known as the shoulder blade. An instrument for measuring the weight of individuals up to 200 kilograms. A questionnaire which is filled in by the participant. Blood fluid that remains after plasma coagulates. Main form in which iron is stored in the liver, spleen and bone marrow. It is an indicator of iron stores for an individual. Visual prompts used to help the participant choose an appropriate response category. Anthropometric measurements of the distribution of body fat. Based on the thickness of subcutaneous fat tissue. Measured by skinfold callipers. Statistical data concerning the relations between social class and demography. The medical laboratories that performed the biochemical analyses of the blood samples for the National Nutrition Survey. An instrument for measuring the height of an individual while standing upright. A recipe consumed by the participant which was matched to a recipe on the recipe list database. A New Zealand Government department which collects and analyses a wide range of data. An instrument for listening to the action of the heart, lungs and arteries. Used when measuring blood pressure in the LINZ® survey. A portion of the participants who undertook the survey. An area of the body below the scapular (shoulder blade) bone on the back. The skinfold covering the subscapular is indicative of fat deposits in that site. The Eru Pomare Mдori Health Research Centre based at the Wellington Medical School of the University of Otago. A database of brand-name foods used to produce lists of food products free from certain components and additives. Auckland Hospital is contracted to the Ministry of Health to provide the Therapeutic Database.
100 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand
Total cholesterol. Transferrin receptors. Triceps. Vacutainers. Vernier bone callipers. White blood cell count. Within-person variation.
This is the sum of all cholesterol fractions found in the blood. It is optimal to have a total cholesterol below 5.2 mmol/L to minimise risk of coronary heart disease. A protein receptor that has a soluble form and a cellular form. It facilitates the entry of iron into cells. Transferrin receptors are an important indicator of iron status. An area of muscle found at the back of the upper arm. The skinfold covering the tricep muscle is indicative of fat deposits in that site. Small vacuum containers that are used for collecting blood samples from participants. Callipers used to measure the elbow width of participants. The number of white blood cells per litre of blood. Variability in an individuals' nutrient intake data between different time periods (otherwise known as intra-person variation).
Food Comes First: Methodologies for the National Nutrition Survey of New Zealand 101
REFERENCES Bergman EA, Boyungs JC, Erickson ML. 1990. Comparison of a food frequency questionnaire and a 3-day diet record. J AM Diet Assoc 90:10 1431­1433. Birkbeck JA. 1983. New Zealanders and Their Diet: Report to the National Heart Foundation of New Zealand on the National Diet Survey 1977. Second revised edition. Dunedin: University of Otago. Bloom F, Brown B, Jeffreson S. 1995. The challenge of dietary assessment: the 24-hour dietary recall methodology used in the 1995 National Nutrition Survey. Proceedings of the South-West Pacific Regional Dietitians Conference, Brisbane, Australia. Brown B, Bloom F, Jeffreson S et al. 1995. Modification of the USDA 24-Hour Dietary Recall Instrument for Use in an Australian National Nutrition Survey. International Conference on Dietary Assessment Methods, Boston, USA. Cypel Y, Tippett K. 1997. Design and Operation: The continuing survey of food intakes by individuals and the Diet and Health Knowledge Survey, 1994­96. NFS Report No 96-1. United States Department of Agriculture-Agriculture Research Services: Beltsville Human Nutrition Research Center. Guenther P, DeMaio T, Ingwerson L et al. 1995. The Multiple Pass Approach for the 24-hour Recall in the Continuing Survey of Food Intakes by Individuals, 1994­96. International Conference on Dietary Assessment Methods, Boston, USA. Lohman, Roche, Martorell (eds). 1988. Anthropometric Standardization Reference Manual. Illinois: Human Kinetics. McDowell M, Briefel R, Warren R, et al. 1990. The dietary data collection system. An automated interview and coding system for NHANES III. Proceedings of the 14th National Nutrient Databank Conference, Ithaca, New York. CBORD Group Inc, 1990: 125­31. Public Health Commission. 1995. National Plan of Action for Nutrition: The Public Health Commission's advice to the Minister of Health 1994­95. Wellington: Public Health Commission. Report of the Nutrition Taskforce. 1991. Food for Health: The report of the Nutrition Taskforce to the Department of Health. Wellington: Department of Health. Russell D, Wilson N. 1991. Life in New Zealand Commission Report Volume 1: Executive overview. Dunedin: University of Otago. Sempos CT. 1992. Invited commentary: Some limitations of semiquantitative food frequency questionnaires. Am J Epidemiol 135:10 1127­1132. Swinburn BA, Sey SJ, Plank L. 1997. Body Composition in Mдori: Report to the Ministry of Health. Auckland: University of Auckland. 102 Food Comes First: Methodologies for the National Nutrition Survey of New Zealand

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