Women (n 160) aged 50 to 65 years were asked to weigh their food for 4 d on four occasions over the period of 1 year, using the PETRA (Portable Electronic Tape Recorded Automatic) scales. Throughout the year, they were asked to complete seven other dietary assessment methods: a simple 24 h recall, a structured 24 h recall with portion size assessments using photographs, two food-frequency questionnaires, a 7 d estimated record or open-ended food diary, a structured food-frequency (menu) record, and a structured food-frequency (menu) record with portion sizes assessed using photographs. Comparisons between the average of the 16 d weighed records and the first presentation of each method indicated that food-frequency questionnaires were not appreciably better at placing individuals in the distribution of habitual diet than 24 h recalls, due partly to inaccuracies in the estimation of frequency of food consumption. With a 7 d estimated record or open-ended food diary, however, individual values of nutrients were most closely associated with those obtained from 16 d weighed records, and there were no significant differences in average food or nutrient intakes. Dietary assessment methods: Weighed intake : Nutritional epidemiologyRecognition of the need for prospective investigation of future individual risk of cancer, and other diseases of middle life, in relation to present day diet is one of the factors that has prompted the search for accurate measures of habitual diet. However, the methodological aims of nutritional epidemiology are inevitably tempered by two opposing interests: that of accuracy in the dietary assessment, and that of feasibility for use in large numbers of individuals, in order to have sufficient power to detect modest relative risks and to demonstrate doseresponse relationships (Bingham, 1987). As part of the preparation for a large European collaborative study of diet and cancer risk (EPIC, European Prospective Investigation of Cancer) we have therefore assessed the accuracy of various methods commonly used in epidemiological studies of diet in large numbers of subjects. We assessed the accuracy of each method by comparison with 16 d of weighed records kept over 1 year.

The European Prospective Investigation into Cancer and Nutrition (EPIC), which covers a large cohort of half a million men and women from 23 European centres in 10 Western European countries, was designed to study the relationship between diet and the risk of chronic diseases, particularly cancer. Information on usual individual dietary intake was assessed using different validated dietary assessment methods across participating countries. In order to adjust for possible systematic over-or underestimation in dietary intake measurements and correct for attenuation bias in relative risk estimates, a calibration approach was developed. This approach involved an additional dietary assessment common across study populations to re-express individual dietary intakes according to the same reference scale. A single 24-hour diet recall was therefore collected, as the EPIC reference calibration method, from a stratified random sample of 36 900 subjects from the entire EPIC cohort, using a software program (EPIC-SOFT) specifically designed to standardise the dietary measurements across study populations. This paper describes the design and populations of the calibration sub-studies set up in the EPIC centres. In addition, to assess whether the calibration sub-samples were representative of the entire group of EPIC cohorts, a series of subjects' characteristics known possibly to influence dietary intakes was compared in both population groups. This was the first time that calibration sub-studies had been set up in a large multi-centre European study. These studies showed that, despite certain inherent methodological and logistic constraints, a study design such as this one works relatively well in practice. The average response in the calibration study was 78.3% and ranged from 46.5% to 92.5%. The calibration population differed slightly from the overall cohort but the differences were small for most characteristics and centres. The overall results suggest that, after adjustment for age, dietary intakes estimated from calibration samples can reasonably be interpreted as representative of the main cohorts in most of the EPIC centres.

Objective: To describe the diversity in dietary patterns existing across centres/regions participating in the European Prospective Investigation into Cancer and Nutrition (EPIC). Design and setting: Single 24-hour dietary recall measurements were obtained by means of standardised face-to-face interviews using the EPIC-SOFT software. These have been used to present a graphic multi-dimensional comparison of the adjusted mean consumption of 22 food groups. Subjects: In total, 35 955 men and women, aged 35-74 years, participating in the EPIC nested calibration study. Results: Although wide differences were observed across centres, the countries participating in EPIC are characterised by specific dietary patterns. Overall, Italy and Greece have a dietary pattern characterised by plant foods (except potatoes) and a lower consumption of animal and processed foods, compared with the other EPIC countries. France and particularly Spain have more heterogeneous dietary patterns, with a relatively high consumption of both plant foods and animal products. Apart from characteristics specific to vegetarian groups, the UK 'health-conscious' group shares with the UK general population a relatively high consumption of tea, sauces, cakes, soft drinks (women), margarine and butter. In contrast, the diet in the Nordic countries, The Netherlands, Germany and the UK general population is relatively high in potatoes and animal, processed and sweetened/refined foods, with proportions varying across countries/centres. In these countries, consumption of vegetables and fruit is similar to, or below, the overall EPIC means, and is low for legumes and vegetable oils. Overall, dietary patterns were similar for men and women, although there were large gender differences for certain food groups. Conclusions: There are considerable differences in food group consumption and dietary patterns among the EPIC study populations. This large heterogeneity should be an advantage when investigating the relationship between diet and cancer and formulating new aetiological hypotheses related to dietary patterns and disease. Of all the environmental exposures diet is a universal exposure, comprising a complex mixture of different compounds that varies over time, space and according to a number of historical, ethnic, religious, agricultural, socioeconomic and psychological factors, at the individual and population levels 1 . The lack of unbiased dietary methods and the difficulty of measuring long-term individual cumulative dietary exposure, when measurements are obtained at fixed point(s) in time of the subject's life, are important methodological limitations for estimating diet accurately as an exposure 2,3 . These drawbacks may partly explain the lack of consistency in estimates of the association between diet and disease, particularly with regard to cancer 4 , and the attenuation in relative risk estimates of the actual relationship between diet and the outcome diseases due to random errors in dietary measurements 5 -7 . Another emerging possible ...

Objective: To evaluate under-and overreporting and their determinants in the EPIC 24-hour diet recall (24-HDR) measurements collected in the European Prospective Investigation into Cancer and Nutrition (EPIC). Design: Cross-sectional analysis. 24-HDR measurements were obtained by means of a standardised computerised interview program (EPIC-SOFT). The ratio of reported energy intake (El) to estimated basal metabolic rate (BMR) was used to ascertain the magnitude, impact and determinants of misreporting. Goldberg's cut-off points were used to identify participants with physiologically extreme low or high energy intake. At the aggregate level the value of 1.55 for physical activity level (PAL) was chosen as reference. At the individual level we used multivariate statistical techniques to identify factors that could explain EI/BMR variability. Analyses were performed by adjusting for weight, height, age at recall, special diet, smoking status, day of recall (weekday vs. weekend day) and physical activity. Setting: Twenty-seven redefined centres in the 10 countries participating in the EPIC project. Subjects: In total, 35955 men and women, aged 35-74 years, participating in the nested EPIC calibration sub-studies. Results: While overreporting has only a minor impact, the percentage of subjects identified as extreme underreporters was 13.8% and 10.3% in women and men, respectively. Mean EI/BMR values in men and women were 1.44 and 1.36 including all subjects, and 1.50 and 1.44 after exclusion of misreporters. After exclusion of misreporters, adjusted EI/BMR means were consistently less than 10% different from the expected value of 1.55 for PAL (except for women in Greece and in the UK), with overall differences equal to 4.0% and 7.4% for men and women, respectively. We modelled the probability of being an underreporter in association with several individual characteristics. After adjustment for age, height, special diet, smoking status, day of recall and physical activity at work, logistic regression analyses resulted in an odds ratio (OR) of being an underreporter for the highest vs. the lowest quartile of body mass index (BMI) of 3-52 (95% confidence interval (CD 2.91-4.26) in men and 4.80 (95% CI 4.11-5.6l) in women, indicating that overweight subjects are significantly more likely to underestimate energy intake than subjects in the bottom BMI category. Older people 'Corresponding

Objective: To describe and compare the consumption of total fish (marine foods) and the fish sub-groups -white fish, fatty fish, very fatty fish, fish products and crustacea, in participants from the European Investigation into Cancer and Nutrition (EPIC) study. Design: Cross-sectional analysis of dietary intake using a computerised standardised 24-hour recall interview. Crude means, means and standard errors adjusted by age, season and day of the week were calculated, stratified by centre and gender. Setting: Twenty-seven redefined centres in the 10 European countries participating in the EPIC study. Subjects: In total, 35 955 subjects (13 031 men and 22 924 women), aged 35 -74 years, selected from the main EPIC cohort. Results: A six-to sevenfold variation in total fish consumption exists in women and men, between the lowest consumption in Germany and the highest in Spain. Overall, white fish represented 49% and 45% of the intake of total fish in women and men,