Standardization of the 24-hour diet recall calibration method used in the European Prospective Investigation into Cancer and Nutrition (EPIC): general concepts and preliminary results

Abstract

Objectives: Despite increasing interest in the concept of calibration in dietary surveys, there is still little experience in the use and standardization of a common reference dietary method, especially in international studies. In this paper, we present the general theoretical framework and the approaches developed to standardize the computer-assisted 24 h diet recall method (EPIC-SOFT) used to collect about 37 000 24-h dietary recall measurements (24-HDR) from the 10 countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC). In addition, an analysis of variance was performed to examine the level of standardization of EPIC-SOFT across the 90 interviewers involved in the study. Methods: The analysis of variance used a random effects model in which mean energy intake per interviewer was used as the dependent variable, while age, body mass index (BMI), energy requirement, week day, season, special diet, special day, physical activity and the EPIC-SOFT version were used as independent variables. The analysis was performed separately for men and women. Results: The results show no statistical difference between interviewers in all countries for men and ®ve out of eight countries for women, after adjustment for physical activity and the EPIC-SOFT program version used, and the exclusion of one interviewer in Germany (for men), and one in Denmark (for women). These results showed an interviewer effect in certain countries and a signi®cant difference between gender, suggesting an underlying respondent's effect due to the higher under-reporting among women that was consistently observed in EPIC. However, the actual difference between interviewer and country mean energy intakes is about 10%. Furthermore, no statistical differences in mean energy intakes were observed across centres from the same country, except in Italy and Germany for men, and France and Spain for women, where the populations were recruited from areas scattered throughout the countries. Conclusion: Despite these encouraging results and the efforts to standardize the 24-HDR interview method, conscious or unconscious behaviour of respondents andaor interviewer bias cannot be prevented entirely. Further evaluation of the reliability of EPIC-SOFT measurements will be conducted through validation against independent biological markers (nitrogen, potassium).

Cooking of meat and fish in Europe—results from the European Prospective Investigation into Cancer and Nutrition (EPIC)

“…In order to standardize information on the consumed food items across countries, systematic questions used for describing a given food were asked, eg cooking method, brand name or fat content. These characteristics of foods were described by socalled 'facets' (Slimani et al, 2000). For each facet a set of 'descriptors' was defined, allowing specifying the facet more precisely.…”

“…When a person reported eating a special meat or fish item, questions (facets) on cooking methods were automatically prompted on the screen with several possible pre-defined answers (descriptors). If a person was not able to answer the question precisely, 'not specific' cooking methods could be chosen (Slimani et al, 2000). The cooking method 'fried' was used as a generic descriptor in EPIC-SOFT.…”

A review of the use of information and communication technologies for dietary assessment

“…Questionnaire evaluating FIRSSt. (13) Examine the level of standardisation of a computer-assisted 24HR (EPIC-SOFT).…”

“…However, the EPIC study results showed problems still existed in the standardisation of the multiplepass 24HR. Further research was needed to compare the actual validity of 24HR intakes across centres using urinary N 2 and K as gold standards, so as to estimate the magnitude of systematic measurement errors across the EPIC centres (13) .A disadvantage of self-administered computerised assessment is that it requires the user to have a minimum level of knowledge about computer use. Certain population groups may have difficulty using a computerised assessment tool, for example, older and less educated individuals (7) .…”

Estimating the distribution of usual dietary intake by short-term measurements

“…The 24 h recall requests information on all foods being eaten the day before with specifications regarding amount and type of food. The instrument has already been tested and applied in ten European countries (Slimani et al, 2000) and seems to be applicable to all study populations in Europe (Slimani & Valsta, 2002). The version being applied is based on a highly standardized computer program and on a common food list.…”