National Dietary Survey among years old individuals in Estonia

Transcription

1 EXTERNAL SCIENTIFIC REPORT APPROVED: 24 March 2017 doi: /sp.efsa.2017.en-1198 Abstract National Dietary Survey among years old individuals in Estonia National Institute for Health Development (Estonia) Eha Nurk, Keiu Nelis, Marge Saamel, Madli Martverk, Liis Nelis This report aims at providing an overview of the objective, sample, methodology and procedure of the National Dietary Survey among adolescents, adults and elderly in Estonia. The methodology for conducting the food consumption survey was compiled in 2007 and harmonised with the European Food Safety Authority s guidelines in For the survey, a random sample stratified by age, gender, ethnicity and place of residence was drawn from the national population register. The sampled subjects were uniformly distributed over four different seasons and the survey calendar was organised to capture an adequate proportion of weekdays and weekend days at population group level. We aimed to collect data from about 6600 (minimum ~3300) subjects in the following age groups: years, years, and years. Detailed food consumption information was collected by using the 24 hour recall method on two non-consecutive days for each participant. In total, data from 2949 adolescents, adults and elderly with a total response rate of 28.1% were eligible after quality control. European Food Safety Authority, 2017 Key words: Adolescents, adults, EFSA s guidelines, elderly, Estonia, FoodEx2, national dietary survey Question number: EFSA-Q Correspondence: DATA.Admin@efsa.europa.eu EFSA Supporting publication 2017:EN-1198

2 Disclaimer: The present document has been produced and adopted by the bodies identified above as authors. This task has been carried out exclusively by the authors in the context of a contract between the European Food Safety Authority and the authors, awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors. Acknowledgements: This work was financially supported by the European Regional Development Fund within the Health Promotion Research Programme TerVE implemented by the Estonian Research Council, the European Food Safety Authority, the Ministry of Agriculture (now Ministry of Rural Affairs), and the National Institute for Health Development. The data gathering was completed in collaboration with SIA GfK Custom Research Baltic Estonia. Suggested citation: National Institute for Health Development (Estonia), Nurk E, Nelis K, Saamel M, Martverk M and Nelis L, National Dietary Survey among years old individuals in Estonia. EFSA supporting publication 2017:EN pp. doi: /sp.efsa.2017.en-1198 ISSN: European Food Safety Authority, 2017 Reproduction is authorised provided the source is acknowledged. 2 EFSA Supporting publication 2017:EN-1198

3 Summary This report aims at providing an overview of the objective, sample, methodology and procedure of the National Dietary Survey conducted among adolescents and adults in Estonia while also highlighting the most significant challenges that were faced during the process of data collection, coding and transmission. In order to get comparable data with other European countries, the Estonian methodology for conducting the food consumption survey compiled in 2007 was harmonised with the Guidance of European Food Safety Authority (EFSA) on General principles for the collection of national food consumption data in the view of a pan-european dietary survey in Survey tools, materials, and the interviewing protocol were developed, pilot tested and evaluated during We aimed to collect data from about 6600 subjects distributed as follows: adolescents from years of age; adults from 18 to 64 years of age; and older individuals from 65 to 74 years of age. In total, 3385 persons were interviewed. After the quality control of the data and exclusion of data from subjects whose written informed consent was missing, the total numbers of subjects with complete data remained 2949: 300 adolescents, 2124 adults, and 525 elderly individuals. The total response rate was 28.1% when, in addition to the original subjects (N=6581), all replacement individuals, who received an invitation letter (N=3907) were considered, but excluding those people with whom contact was not obtained (wrong address, moved abroad etc.). For the survey, a random sample stratified by age, gender, ethnicity and place of residence was drawn from the national population register. The sampled subjects were uniformly distributed over four different seasons in order to more precisely capture the inter-seasonal variability in food consumption patterns, and the survey calendar was organised to capture an adequate proportion of weekdays and weekend days at population group level. Detailed food consumption information was collected by the 24 hour recall method using computer assisted personal interview on two nonconsecutive days for each participant. Observation days were about 14 days apart. For data entry, we used our in-house software NutriData pro, which also participated at EFSA s software ring-trial in within the project Dietary Monitoring Tools for Risk Assessment. NutriData pro allows foods and beverages to be entered directly from the Estonian Food Composition Database and to describe them. It incorporates twelve combined facets from the EFSA FoodEx2 food classification and description system. Facets include, for example, processing and preservation methods, packaging, origin, cultivation, etc. The software also has a built in picture book, which makes the quantification of foods and beverages considerably easier and faster. The fieldwork was performed by qualified interviewers of a professional research company, SIA GfK Custom Research Baltic Estonia, under the supervision of our institute. Data collection was performed from October 2013 to April During the survey, several problems appeared: people s extremely low interest to be recruited, resigned interviewers due to complicated survey methodology, difficulties to find new qualified interviewers, technical failures with data synchronization between computer networks, complexity of data transmission and FoodEx2 coding. Despite of the mentioned problems, we can conclude that our survey was successfully conducted and the results will significantly contribute to the fully harmonised pan-european Food Consumption Survey called What s on the Menu in Europe? (EU Menu). Moreover, the National Dietary Survey among adolescents, adults and elderly in Estonia was very important as it was the first population survey in our data collection history for adolescents and elderly, and for adults it filled a 17-year gap from the previous survey. 3 EFSA Supporting publication 2017:EN-1198

4 Table of contents Abstract...1 Summary Introduction and objectives Background and terms of references as provided by the requestor Description of the protocol of the survey Study population and exclusion criteria Sampling frame Sampling method and design Sample size Strategy to achieve an adequate response rate and the initial sampling size Legal and ethical aspects Dietary survey tools Food frequency questionnaire Dietary recall Food description Determination of portion sizes Dietary software Other information Questionnaires Anthropometric measurements Food supplements Administration of the interview Selecting the examination site Content and organization of the study visits First contact First home visit Second home visit Recruitment and training of the staff Selection of the fieldwork staff Training Quality assurance Data management Dissemination and publicity Special issues/challenges...18 Conclusions...19 References...20 Abbreviations...21 Annex A - Food Frequency Questionnaire, National Dietary survey , Adolescents, adults and elderly (11-74 years)...22 Annex B - General questionnaire, National dietary Survey , Adolescents (11-17 years)...22 Annex C - General questionnaire, National dietary Survey , adults and elderly (18-74 years)22 Annex D - Instructions for anthropometry, instructions for measuring body weight, height and waist circumference EFSA Supporting publication 2017:EN-1198

5 1. Introduction and objectives The mapping and analysis of different health surveys conducted in Estonia in the past couple of decades has showed that there was a need for up to date, comparable, high quality food consumption data that can be used to perform food related risk assessment of the population. The last and so far only national dietary survey in Estonia was conducted in 1997 (Pomerleau et al, 2001). The methodology for conducting a new national dietary survey in Estonia was compiled in 2007 by a working group of food safety and nutrition experts. The methodology was created as a basis for collecting detailed and high quality food consumption data on the individual level that was representative of the whole population. The second part of the National Dietary Survey targeting adolescents, adults and elderly people in Estonia (the survey on infants and children started one year earlier) was planned to take place in Availability of uniform food consumption data is fundamental for several functions of Estonian and European authorities. Since the production of comparable food consumption data can be achieved only by means of surveys with a common methodology and instruments, it is suggested to harmonize the Estonian national dietary survey methodology taking into account the new recommendations from the European Food Safety Authority (EFSA). In 2009, EFSA published General principles for the collection of national food consumption data in the view of a pan-european dietary survey (EFSA, 2009). Due to similar aims for food consumption data collection on the national and European level, the harmonisation of the existing Estonian Dietary Survey methodology with the guidelines of EFSA was considered feasible and recommended. The resulting harmonised survey methodology is expected to provide comparable food consumption data in relation to the characteristics of the population that complies with the data needs of national authorities and of EFSA. Taking into account the guidelines of EFSA, the survey methodology was harmonised and the survey protocol and questionnaires were developed to use for data collection first in the pilot study and thereafter in the National Dietary Survey. For harmonisation of methodology of the National Dietary Survey with EFSA s guidelines, an interdepartmental working group was assembled by the National Institute for Health Development. The working group compared an existing national dietary survey s methodology with the new guidelines of EFSA and decided to follow the methodological aspects as presented in the guideline document of EFSA. For harmonisation of food description in the National Dietary Survey with the guidelines of EFSA, another working group was assembled to further compare and decide on the list of food descriptors to be included in the National Dietary Survey. The working group reviewed and decided to use the list of food descriptors based on the food classification system FoodEX2 developed by EFSA (EFSA, 2011) Background and terms of references as provided by the requestor Access to uniform food consumption data across the EU Member States is fundamental for several functions of EFSA, European authorities and other bodies and stakeholders. In addition to food safety monitoring of existing hazards and evaluation of emerging risks, standardised food consumption data will be very useful in establishing new and updating existing legislation on the safety of foods. A long term objective of EFSA is the organisation of a fully harmonised pan-european Food Consumption Survey, this project is called What s on the Menu in Europe? (EU Menu). The EU Menu survey is planned to be carried out in whereas planning, harmonisation of protocols and implementation and piloting of methods have already started in 2010 for the different target population groups. In October 2009, the EFSA Expert Group on Food Consumption Data endorsed the Guidance of EFSA on General principles for the collection of national food consumption data in the view of a pan- 5 EFSA Supporting publication 2017:EN-1198

6 European dietary survey 1. The main objective of this Guidance is to recommend general principles for the collection of dietary information that can be used to calculate exposure to all possible biological agents and chemical substances considered by EFSA s Scientific Panels as well as estimating intake of nutrients and vitamins. In January 2010, EFSA started the Article 36 project (CFP/EFSA/DATEX/2009/02) Pilot study for the Assessment of Nutrient intake and food Consumption Among Kids in Europe (PANCAKE) (Ocké et al. 2012), coordinated by RIVM (The Netherlands) to develop and test tools and procedures for the collection of individual food consumption data for infants, toddlers and other children up to 10 years of age. In January 2011, EFSA started the Article 36 project (CFP/EFSA/DATEX/2010/02) Pilot study in the view of a Pan-European dietary survey Adolescents, adults and elderly (PANEU) (Ambrus et al, 2013), coordinated by the Hungarian Food Safety Office to develop and test similar tools and protocols for the different adult population groups. Further, since December 2010, EFSA collaborates with the International Agency for Research on Cancer (IARC) through a negotiated procedure contract (NP/EFSA/DATEX/2010/01) in order to get the EPIC-SOFT dietary software and related interview and data management tools and databases developed and adapted according to the needs of EFSA and to ensure that this software can be used by EU Member States for their dietary surveys (EU Menu), (IARC, 2013). The first series of support to the national dietary surveys was provided by means of the call for tender CFT/DCM/2011/02. Two applicants (from France and Estonia) were awarded a contract in October The proposed call for tenders is aimed at supporting at least three (up to six) EU Member States, which are having the governmental mandate to carry out a national dietary survey in the period from 2012 to Resources will be made available to support the adaptation of the methodology used in these studies to comply, as much as possible, with the general principles proposed in the above mentioned EFSA Guidance. The dietary data collected through the activity should be available to EFSA s scientific activities without restriction for its use. The objectives of the contract resulting from the present procurement procedure are as follows: objective 1: To adapt the methodology used in the national food consumption survey, as much as possible, according to the above mentioned EFSA Guidance document objective 2: To provide the national food consumption and related data collected within the survey to EFSA in the format required by EFSA. This contract was awarded by EFSA to the National Institute for Health Development Contractor: National Institute for Health Development Contract title: Support to national dietary surveys in compliance with the EFSA Guidance on General principles for the collection of national food consumption data in the view of a pan-european dietary survey second support. Contract number: CT/EFSA/DCM/2012/01-CT01 2. Description of the protocol of the survey The National Dietary Survey among Estonian adolescents, adults and elderly was commenced in fall of The methodology of the survey was mostly in line with the guidelines of EFSA. However, the aspects that differed in the Estonian methodology included the number of replicates in diet recalls, the 1 The guidance of EFSA has been updated in December 2014 and is available as Guidance on the EU Menu Methodology at EFSA Supporting publication 2017:EN-1198

7 distribution of the sample and the age range of the study population. Based on the harmonised National Dietary Survey methodology, individuals aged years were included in the sample. Data collection was conducted using a dietary recall by computer assisted personal interview (CAPI) including two non-consecutive days about two weeks apart. In addition, a food frequency questionnaire (FFQ) was filled in by each participant. A country-specific food picture bank was used to assist with the determination of portion sizes. The list of food descriptors based on the FoodEx2 food classification system from EFSA was used. The anthropometric measurements of the subjects were taken and general data on personal and household characteristics were collected. The data collection interviews were conducted during face to face visits with the subjects and the sampling was uniformly distributed over four seasons and week days, including holidays. In order to deal with non-response, three matched replacement individuals were drawn for each subject invited. The in-house created NutriData pro software was used as the data entry tool in the survey. The survey protocol and questionnaires were developed taking into account the guidelines from EFSA. A pilot study was conducted in fall of 2012, where in total 85 individuals were interviewed. Evaluation of the results of the pilot study and necessary adaptations and improvements in methodology were done during the first half of The data collection period of the Estonian National Dietary Survey lasted from October 2013 to April Study population and exclusion criteria A sample population of the Estonian Dietary Survey included residents of Estonia, in the time period of the survey, excluding institutionalised subjects (~0.4% of the total children population and ~1.3% of the adult population) and individuals who do not speak Estonian or Russian. Subjects living on the two biggest overseas islands were included in the survey. The second part of the Estonian National Dietary Survey targeted adolescents in the age of years, adults in the age of years, and elderly people in the age of years Sampling frame All individuals in the age of years were considered as the target population. Based on the data from Statistics Estonia, a representative sample was proportionally calculated considering four sampling layers: age, gender, ethnicity and place of residence according to the smallest NUTS (Nomenclature des Unités Territoriales Statistiques) region classification of regional units of the European Union. The national population registry was determined as the sampling frame and a random sample was drawn according to calculations. Initially, only exact addresses of potential participants (original subject + three replacement subjects) were obtained, but later on, a direct contact number (landline or mobile) was requested as well, if available in the register. In all, 26,324 records were sampled from 1,034,555 eligible records. The sample of 6,581 participants covered 0.64% of the population in the age of years. Details on the sample frame are presented in Table Sampling method and design A stratified random sampling method at individual level was used to select the subjects using age, gender, ethnicity and place of residence as predetermined sample strata as shown in Table 1. The sampled subjects were uniformly distributed over four different seasons in order to more precisely capture the inter-seasonal variability in food consumption patterns. The survey calendar was organised to capture an adequate proportion of weekdays and weekend days at population group level, and if possible, holidays were included as well. 7 EFSA Supporting publication 2017:EN-1198

8 Table 1: The sample frame of the Estonian National Dietary Survey by age, gender, ethnicity and place of residence Sampling layer years years years Eligible Eligible Sample, population, Sample, population, N N N N Eligible population, N Sample, N Age 98, , , Gender Males 50, , , Females 47, , , Ethnicity Estonians 76, , , Non-Estonians 21, , , Place of residence Northern Estonia (Harju county) 36, , , Western Estonia (Hiiu, Lääne, Pärnu and Saare counties) 12, , , Central Estonia (Järva, Lääne-Viru and Rapla counties) 11, , , Northeastern Estonia (Ida-Viru county) 10, , , Southern Estonia (Jõgeva, Põlva, Tartu, Valga, Viljandi and Võru counties) 27, , , Sample size The initial aim was to collect data from about 6600 adolescents, adults and elderly divided into three age groups distributed as follows: adolescents years of age (N~400 out of 791), adults years of age (N~2500 out of 5000), and elderly years of age (N~400 out of 800) with 50% expected response rate. In total, 350 adolescents, 2442 adults and 593 elderly people were recruited. After the quality control of data and the exclusion of data from people whose written informed consent was missing, the total numbers of these three age groups remained 300, 2124, and 525, respectively. The total number of valid subjects per age group is presented in Table 2. Table 2: Number of participants in the Estonian National Dietary Survey of adolescents, adults and elderly by age and gender Age class Number of subjects interviewed Number of subjects provided one day data (a) Valid number of subjects (provided two days data) (a) Males Females Total Males Females Total Males Females Total Adolescents, years Adults, years Elderly, EFSA Supporting publication 2017:EN-1198

9 65-74 years (a): Subjects remained after quality control and removal of data on people without informed consent 2.5. Strategy to achieve an adequate response rate and the initial sampling size In order to deal with non-response, three matched replacement individuals were drawn for each subject to be invited. The replacement individuals were invited only when needed. In order to emphasize the importance of the survey, the National Institute for Health Development, in collaboration with the Ministry of Agriculture (now Ministry of Rural Affairs), drew up an extensive media plan starting with press releases already a couple of months before the start of the survey. The fieldwork started with a press conference, where the Minister of Agriculture and principal investigator of the survey explained the necessity of the survey. A special website ( was also prepared for participants, where they could find additional information about the survey. Those who had received an invitation to participate could register for the survey at the same website. Despite of these activities, the interest to participate was extremely low. Additional attempts were made to improve the recruitment of participants. These included: arrangement of various media notifications (newspapers, magazines, TV and radio advertisements etc.) simultaneously with each sending wave of the invitation letters, request for the phone numbers of sampled people from the population registry, personal visits to the participants homes by the interviewers in order to make arrangements for a suitable time for the interviews. The reasons for non-participation varied, they mainly included busy time schedules and lack of interest to participate, also wrong addresses in the population registry or moving abroad, and the complexity and comprehensiveness of the survey. The final response rate was 28.1% and details by subgroups are presented in Table EFSA Supporting publication 2017:EN-1198

10 Table 3: Response rates in the Estonian National Dietary Survey among year-old participants by age, gender, ethnicity and place of residence Sampling layer Adolescents years Adults years Elderly years Invitation letter received, N Participated, N Response rate Invitation letter received, N Participated, N Response rate Invitation letter received, N Participated, N Response rate Age , , ,6 Gender Males , , ,3 Females , , ,9 Ethnicity Estonians , , ,2 Non-Estonians , , ,3 Place of residence Northern Estonia (Harju county) , , ,8 Western Estonia (Hiiu, Lääne, Pärnu , , ,4 and Saare counties) Central Estonia (Järva, Lääne-Viru and , , ,0 Rapla counties) Northeastern Estonia (Ida-Viru county) , , ,9 Southern Estonia (Jõgeva, Põlva, Tartu, Valga, Viljandi and Võru counties) , , , Legal and ethical aspects The survey was approved by the Tallinn Medical Research Ethics Committee, and the data collection was performed according to the rules of the Data Protection Act. An informed consent for participation was signed for each adolescent by their parent or guardian, and adults and elderly people also gave their own informed consent to participate in the survey. 3. Dietary survey tools 3.1. Food frequency questionnaire A comprehensive self-administered FFQ including ~200 food items divided into 15 groups (bread; porridges and grain products; vegetables; fruits; potato; soy products; egg; milk and dairy products; meat and meat products; fish and marine products; fats and sauces; sugar, sweets, nuts, seeds and bakery products; drinks; other foods; food supplements) was used. The first six pages of the questionnaire are given as an example in Annex A Dietary recall The 24 hour dietary recall method was applied for all participants and the data was entered using the NutriData pro software. Data were collected for two non-consecutive days. The time interval between the two replicates had to be approximately two weeks, and the observed days had to be different weekdays. More information on the dietary data collection is found in Section EFSA Supporting publication 2017:EN-1198

11 Food description The foods consumed were described in detail, and industrially produced composite foods or homemade dishes were disaggregated as much as possible into their main ingredients at a level that can be reported by the subject. The list of facet descriptors included in the data collection of the Estonian National Dietary Survey were selected, coded and described according to the food classification system FoodEx2 of EFSA. The facet descriptors included in the 24 hour recalls are the following: Food producer and brand this information was reported by the subject with the help of existing food packages or the food brand catalogue created for the survey Fat content this was asked in case of milk products, fats and meat products with 0.1% precision Production method plant and animal foods that have been produced organically or using genetically modified organisms were described by the subject Production or preparation place of the food Country of production Packaging material if the food was surrounded with multiple packaging materials, the one in direct contact with the food was described Preservation technique and preparation method Extent of cooking this facet describes the intensity of heat treatment having been applied to a food item in the categories of meat, fish-seafood, eggs, milk and bread Part-consumed this was asked in case of fruit, vegetables, legumes, fish, meat and meat products Fortification agent this was asked in case of margarines and oils, milk products, breakfast cereals, soy products, eggs, juices and baby foods Flavour note this facet allows providing information on flavour or taste notes Sweetening agent only added (not naturally occurring) sweetening agents were described Alcohol content this was asked while interviewing adults and elderly If any of the named descriptors could not be reported by the subject, the corresponding descriptor was marked as unknown Determination of portion sizes Portion sizes were determined either by commonly used household measures or by a country-specific electronic food picture bank. The country-specific food picture bank was developed for the NutriData pro software. The picture bank consists of 333 series of general and country-specific food pictures. Each food series includes 4-10 pictures. Each picture in the food series represents a different portion size, i.e. ¼, ½, ¾, 1 (Figure 1). The standard portion sizes were compiled based on data from the previous national dietary survey conducted in Estonia, national food recommendations and the regularly updated data available from the national food composition database. Although the picture bank includes pictures based on adults consumption patterns, the photos of foods on dining utensils of different sizes and various portion quantities allow to use them for the estimation of adolescent s portions as well. All composite dishes are photographed on three different plate sizes (20 cm, 24 cm, 27 cm), as seen on Figure EFSA Supporting publication 2017:EN-1198

12 Beverages are photographed in four different glass and cup sizes (200 ml, 270 ml, 320 ml, 420 ml and 90 ml, 170 ml, 270 ml, 340 ml, respectively). The picture bank also includes pictures of whole fruits and vegetables in different sizes and different physical forms of foods (i.e. grated, chopped, hashed, etc.). The picture bank was used as a portion size estimation tool in addition to household measure units and grams or ml units to better estimate the consumed food quantities. The various possibilities (household measures and a variety of different picture series described above) for portion estimation reduce a bias on food quantity determination. The suitability and accuracy of the country-specific picture book based on the electronic picture bank has been successfully validated with a focus group testing involving 87 persons in the age of years. For testing, a paper-form picture book based on the picture bank was created, containing picture series of 31 foods and one drink. The amounts of food given in the picture book were in ascending order, but without indications on the amounts in grams. Instead, the letters A, B, C, D, E, F, G, H were used (the number of letters corresponds to the number of pictures in the series). Figure 1: Food series in the NutriData pro picturebank: hotpot (on 24 cm plate) 12 EFSA Supporting publication 2017:EN-1198

13 Figure 2: Plate selection in the NutriData pro picture bank The testing was based on the portion assessment principle (Nelson and Haraldsdottir, 1998), in which the tester provided the subject with previously weighed food portions and showed the subject which picture series from the picture book should be used for assessment. Then, the subject compared the portion of food given to him/her on a plate with the pictures shown in the picture series and marked the amount he/she thought to be correct in the questionnaire. Each amount of food given to the subject could be found in the picture book. Each subject was requested to assess food portions based on all picture series of the picture book: 20 foods could be matched with a picture series depicting the same food that was given to the subject on a serving dish; five foods and one drink could be matched with a picture series depicting the same food or drink, but the serving dish was different in size or shape; six foods could be matched with a picture series depicting a similar food. The results showed that if the food given in the picture series and the food on the subject s plate were an exact match, the assessment was more precise and the correct amount was chosen by a higher number of subjects. Therefore, to conduct the dietary survey, we doubled the amount of picture series in the picture book to increase the probability of finding the exact or partial match to the consumed foods when assessing food portions. As a result of testing, the average accuracy within a range of +/- 1 photo of all 31 foods and water (as an example of drink quantity estimation) was 89% Dietary software In-house developed NutriData pro software was used as the data collection tool. This software also participated and was tested at EFSA s software ring-trial in within the project Dietary Monitoring Tools for Risk Assessment (Gavrieli et al, 2014). NutriData pro is specially created for conducting dietary surveys allowing designing different questionnaires, e.g. regular food habits, diet recalls or freely composed general questionnaire modules for collecting non-diet information of the survey participants. The software has linkages with the food composition database and a programme developed for calculating menus, allowing the use of predetermined foods and recipes during the data entry. However, if necessary, there remains the possibility to add or remove some components in predetermined recipes during the data entry. In the NutriData recipe calculation system, the yield factor is applied at the recipe level and the retention factors at the ingredient level. When applying the yield factor, the system doesn t distinguish between ingredients that absorb moisture (e.g. pasta products) and those that lose moisture (e.g. meats). Therefore, when dry ingredients are used in a recipe, liquid is always added separately. There are also five different levels of retention factors, depending on the intensity of the treatment. The food composition database includes information on ~2700 most consumed foods (including ~1000 common recipes) in Estonia, information on 59 nutrients, and reflects the average values found in Estonian foods. Availability of this database certainly helps to minimise the interviewer bias. To make it more suitable for extensive fieldwork, an offline version of the software was developed so 13 EFSA Supporting publication 2017:EN-1198

14 that data could be collected without internet access and synchronized with the central database when the internet connection is available. The research platform of NutriData pro used to conduct dietary surveys includes the following general characteristics: information on all foods and beverages consumed during the survey can be entered and coded automatically according to the common rules; during the data inputting, each item can be searched, described, quantified and checked using the pre-entered common rules; standardised level of food description; whatever way the food/dish is quantified during the interview, the food quantities are entered into the system as finally consumed (e.g. cooked), using appropriate entries from the food list included in the data entry tool; regular updating of database, so that new foods, recipes and other reported information can be added; provision of output files with valid population food, energy and macronutrients intake data in electronic format. These output files are functional for performing statistical analysis; linkage with the different parts of NutriData pro and the national food composition database: portion sizes, standard recipes, food composition, yield and retention factors, energy requirements; enabling to choose and change the facets and descriptors that are used to describe foods that have been consumed; food facet descriptors applicable to FoodEx2 developed by EFSA. However, as the final version of FoodEx2 provided by EFSA became available after the data collection was completed, this function could not be automatically applicable and several adoptions were required during FoodEx2 coding Other information Questionnaires Socio demographic information Socio demographic information was collected through a standardised questionnaire, including amongst others the following information: gender birth day, month and year age in years region, area or city of residence self-defined ethnic group subject identified as being in special conditions subject identified as having a particular eating pattern size of household number of individuals in the household labour status of the subject labour status of the mother of the subject (only applicable in case of adolescents) 14 EFSA Supporting publication 2017:EN-1198

15 labour status of the father of the subject (only applicable in case of adolescents) description of the current education level or highest diploma obtained by the subject description of the current education level or highest diploma obtained by the mother (only applicable in case of adolescents) description of the current education level or highest diploma obtained by the father (only applicable in case of adolescents) description of the activity level Questionnaires for collecting background information are presented in Annex B. Physical activity An international physical activity questionnaire (IPAQ) short form was used Anthropometric measurements Height, weight, and waist and hip circumferences were measured for all participants. Guidelines used for the anthropometric measurements are in Annex C Food supplements The intake of food supplements was recorded during the 24 hour recalls and also with the FFQ. The intake of food supplements (total of 88 food supplements as coded in FoodEx2) was recorded as open-ended answers by type of supplement, producer and brand name, and the consumed amount (i.e. number of drops, pills, sachets etc.), because food supplements were not fully covered in the Estonian Food Composition Database. 4. Administration of the interview 4.1. Selecting the examination site Most of the interviews were performed at the respondent s home. In cases where the respondent agreed to participate, but refused to perform the interview at their home, an alternative suitable site was allowed, e.g. the National institute for Health Development, the respondent s work place, a library, a quiet café, etc Content and organization of the study visits First contact The sampled people received an invitation letter with a brief introduction of the survey by regular mail. They were asked to give feedback about their intention to participate in the survey either through filling a registration form on the survey website, by calling the fieldwork coordinator or sending a written response in the prepaid response form by mail. Upon the person s agreement the interviewer contacted the people via telephone to make an appointment. As the response rate was very low, despite of the efforts to recruit people with media notifications, we requested the phone numbers of sampled people from the population register and the recruitment strategies for the interviewers changed. Therefore, from December 2014 the interviewers could contact the potential respondent themselves, without having to wait for the response to the mail invitation. Although this somewhat facilitated the process of contacting the sampled people, there were still about 30% of them whose phone numbers were not available in the register. If the phone 15 EFSA Supporting publication 2017:EN-1198

16 number was not available or the given number was incorrect, the interviewers had to visit the person s home to try to recruit them and arrange an appointment First home visit The interviewers visited the respondents home. This visit consisted of the following parts: The interviewer introduced the aim and nature of the survey and gave an overview of the questionnaires and examination The interviewer took an informed consent from adults and elderly, and in case of adolescents, from a parent or guardian The interviewer conducted the first interview (CAPI-method) to obtain background data (socio-demographics, general information on health condition and diet, physical activity etc.) The interviewer performed anthropometric measurements: height, weight, and the waist and hip circumferences The interviewer performed a 24 hour food interview using the recall method The interviewer gave the participant a FFQ and explained how to fill it in The interviewer and the participant agreed on the second appointment to conduct the second food interview Second home visit The second home visit took place approximately two weeks after the first home visit and consisted of the following parts: The second 24 hour food interview was performed using the recall method The interviewer checked the FFQ for completeness, and asked additional questions if needed The interviewer handed over an incentive to the respondent. All of the participants, who requested, received a feedback sheet with individual results after the quality of collected data was assured (usually 3-4 months after participation). The feedback form included the persons individual results (anthropometric measurements, physical activity, and mean energy and macro- and micronutrient intake based on two 24 hour food recalls) compared to the ageand gender-specific reference values and national food recommendations Recruitment and training of the staff Selection of the fieldwork staff The fieldwork was performed by a professional research company, SIA GfK Custom Research Baltic Estonia, as a sub-contractor. The criteria for recruitment of qualified interviewers were: an adequate nutritional training, a certificate of nutritional training or nutritional courses in university, excellent Estonian and/or Russian language skills, average computer skills Training We performed three types of trainings for the interviewers: 16 EFSA Supporting publication 2017:EN-1198

17 In collaboration with the Department of Food Processing at Tallinn University of Technology, full day weekend courses were arranged for those interviewers who did not have adequate nutritional background covering the following topics: Nutrition in general; Food energy and nutrient content; Food and nutrition recommendations; The different age groups for food recommendations; Cooking methods, food preservation and processing losses; Food labelling; Food weight assessment and practical exercises. The research company trained those interviewers who did not have experience in interviewing (e.g. interviewers with nutrition background). Besides the technical issues, this part of training also covered the ethical aspects Our institute trained all interviewers to conduct this particular dietary survey, including a full day general assemble of the interviewers and two days of individual trainings (2-3 hours per day with groups of 1-2 interviewers per trainer) allowing a few days of self-practising between those two days. All candidates for interviewers had to pass a test at the end of this part of training. 5. Quality assurance Survey tools, materials, and interviewing protocol were pilot tested and evaluated during As a result of the pilot study, some improvements and changes were made: questions in the general questionnaire were revised for clarity, the survey tool was modified with drop-down and uniform answer choices and with setting logical control limits for certain questions in order to reduce input errors, the survey tool was complemented by the opportunity to compose recipes, the list of composite foods in Estonian Food Composition Database was upgraded with several frequently consumed foods, an offline version of the software was created to reduce data loss due to possible poor or interrupted internet connection at respondent s home, instructions for the interviewers and materials for trainings were updated. Although the research company organised the fieldwork, we still supervised the interviewing process. The recruitment of participants was regularly monitored, and monthly overviews were produced, including the number of recruited people, refusals, status of interviews (how many started and completed, also drop-outs), distribution of weekdays and seasonality. Because the recruitment was very poor during the first months of the survey, we extended the fieldwork period by eight months to get more unified seasonal distribution and to increase the number of respondents. All collected data were quality checked by our survey team. The completed interviews were sent to us online whereupon data entries from 24 hour food diaries were routinely checked by our team members, who have nutritional background. During the quality control, all interviews entered by the interviewers were checked one by one. If needed, corrections and replacements were made based on the information provided by the facets and the interviewer s remarks. A majority of the replacements involved foods and beverages entered in incorrect form. For example, raw instead of cooked (meat, 17 EFSA Supporting publication 2017:EN-1198

18 vegetables), powder instead of prepared food (coffee, cocoa) and dry ingredient instead of cooked ingredient (pasta, rice). If the Estonian Food Composition Database contained a more accurate or suitable food than the one entered by the interviewer, replacements were made as well. In case of deficient data, the quality checkers contacted the interviewer and asked to provide specifications, if possible. From time to time our team gave feedback to all of the interviewers about the most common mistakes, and also slackness when it appeared to take place. 6. Data management After quality assurance, the dietary data were coded according to FoodEx2 classification. Standard procedures for data cleaning were applied for background data collection, and the non-realistic entries were removed or corrected by using logic controls, e.g. age of participant was checked by subtracting birth date from the date of entering to the study; number of children in the household was checked against the number of household members and family model; hours of daily activities such as physical activity, screen time and sleeping were summed-up and checked for 24h; anthropometric measurements were checked for outliers; etc. Food consumption data were checked at nutrient level for the outliers with regard of micro- and macronutrient intake, as well as energy intake. Outliers were checked separately, using food composition data and, if needed, corrections were made. Estimated energy and nutrient intakes were also compared with age- and gender-specific dietary requirements. After the initial FoodEx2 training and during coding, a continuous data harmonization and quality control system was implemented by providing the coders with an opportunity to discuss the specifics of the work and ask questions in real time, as they proceeded. Also, manual checks of the FoodEx2 coding were conducted and corrections were made, if needed. 7. Dissemination and publicity Methodology and preliminary results of the survey were first briefly presented in the national nutrition conference on November 5 th, 2015, and the final results have thereafter been presented in several other conferences. A comprehensive survey report including the methodology and results will be compiled during The standard statistical tables (NIHD Database) and report alongside the survey results will be published in our institute s web page (NIHD page). The survey data will be also used for: population nutrition-related health risks assessment, identification of risk groups and the related burden of disease food safety risk assessment development of a national information system to reduce health risks caused by the diet of the population writing bachelor s and master s theses, and possibly doctoral dissertations as well writing scientific articles to be published in the Estonian and international peer-reviewed journals. 8. Special issues/challenges Since the study was of wide scope and more complex than usual surveys, many different problems appeared during the fieldwork: the people s lack of interest to be recruited, a number of resigned interviewers and finding new qualified interviewers, technical failures with data synchronization 18 EFSA Supporting publication 2017:EN-1198

19 between computer networks. Due to these problems we had to adjust our schedule several times and postpone the final date of the fieldwork. Actions used to increase the recruitment of the survey participants were described in Section 2.5. Motivation of the interviewers was another serious problem and many of them resigned in the course of fieldwork. Due to resignation we had to train additional interviewers several times. The reasons for resignation were different, but the most prevalent were the complicacy of the survey, difficulties to persuade people to participate in such an extensive survey, and non-remunerative job by the research company. To solve these problems a bonus system was implemented by the research company, and also an upgrade of the software that improved synchronization speed, making the survey platform simpler and more user friendly and helped to motivate the interviewers to continue fieldwork. One of the most challenging and underestimated tasks, both in terms of time expenditure and complicacy, was the coding of the results of the survey according to FoodEx2 classification, and the final delivery transmission. Changing the codes according to the exact requirements of EFSA was time-consuming. In the future, the level of food description during the data collection could be based on FoodEx2 facet descriptor system. Another aspect that made the coding complex was that the current reporting hierarchy of FoodEx2 does not have certain national cuisines represented and is therefore also lacking some specific types of foods (e.g. oven-baked dairy-based puddings, kissels, various quark-based desserts, savoury dumplings, kama flour, etc). The difficulties arise mainly when the foods are part of a composite food. In light of the above, it is advisable to foresee and dedicate enough time in advance of the data transmission deadline to prepare the data according to the requirements of EFSA. A specific training on the data transmission aspects to the people that will be responsible for submitting the data to EFSA would also be very helpful. Finally, more detailed step-by-step and easy-to-follow guidelines for data formatting and data transmission using DCF would be appreciated. Conclusions The National Dietary Survey among Estonian adolescents, adults and elderly filled a 17-year-long gap after the previous dietary data collection in The methodology for conducting the food consumption survey was compiled in 2007 by a working group of food safety and nutrition experts. The methodology was created as a basis for collecting detailed and high quality food consumption data on the individual level representative of the whole population. Within the current contract, the Estonian methodology was harmonised with EFSA s guidelines in order to get comparable data with other European countries as availability of uniform food consumption data is fundamental for several functions of national and European authorities. Survey tools, materials, and the interviewing protocol were developed, pilot tested and evaluated during Data collection was performed from October 2013 to April However, several obstacles appeared during the survey, starting from the people s extremely low interest to be recruited, resigned interviewers due to complicated survey methodology, difficulties finding new qualified interviewers, technical failures with data synchronization between computer networks, and ending with FoodEx2 coding. Despite of the above, it can be concluded that our survey was successfully conducted and the results will significantly contribute to the fully harmonised pan-european Food Consumption Survey EU Menu EFSA Supporting publication 2017:EN-1198