The validity coefficient of dietary questionnaire measurements can be estimated from a triangular comparison between questionnaire, reference, and biochemical marker measurements with the method of ...triads. The method assumes that the measurements are linearly related to true intake and have independent random errors. We applied the method of triads to examples from the European Prospective Investigation into Cancer and Nutrition. In some examples, Heywood cases occurred, ie, the estimated validity coefficients were > 1 or the validity coefficients were not estimable. Such results are caused by random sampling fluctuations or violation of the model assumptions. One possible violation is a positive correlation between the random errors of questionnaire and reference measurements. We used a bootstrap method to estimate CIs for the validity coefficients. Validity studies with several hundred subjects, more accurate biochemical indicators of dietary intake, or both, are needed to estimate validity coefficients precisely and avoid complications with the bootstrap method.
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.
Concerns have been raised about the quality of reporting in nutritional epidemiology. Research reporting guidelines such as the Strengthening the Reporting of Observational Studies in Epidemiology ...(STROBE) statement can improve quality of reporting in observational studies. Herein, we propose recommendations for reporting nutritional epidemiology and dietary assessment research by extending the STROBE statement into Strengthening the Reporting of Observational Studies in Epidemiology-Nutritional Epidemiology (STROBE-nut).
Recommendations for the reporting of nutritional epidemiology and dietary assessment research were developed following a systematic and consultative process, coordinated by a multidisciplinary group of 21 experts. Consensus on reporting guidelines was reached through a three-round Delphi consultation process with 53 external experts. In total, 24 recommendations for nutritional epidemiology were added to the STROBE checklist.
When used appropriately, reporting guidelines for nutritional epidemiology can contribute to improve reporting of observational studies with a focus on diet and health.
Concerns have been raised about the quality of reporting in nutritional epidemiology. Research reporting guidelines such as the Strengthening the Reporting of Observational Studies in Epidemiology ...(STROBE) statement can improve quality of reporting in observational studies. Herein, we propose recommendations for reporting nutritional epidemiology and dietary assessment research by extending the STROBE statement into Strengthening the Reporting of Observational Studies in Epidemiology – Nutritional Epidemiology (STROBE‐nut). Recommendations for the reporting of nutritional epidemiology and dietary assessment research were developed following a systematic and consultative process, co‐ordinated by a multidisciplinary group of 21 experts. Consensus on reporting guidelines was reached through a three‐round Delphi consultation process with 53 external experts. In total, 24 recommendations for nutritional epidemiology were added to the STROBE checklist. When used appropriately, reporting guidelines for nutritional epidemiology can contribute to improve reporting of observational studies with a focus on diet and health.
Abstract
Objectives:
To describe and compare the consumption of dairy products in cohorts included in the European Prospective Investigation into Cancer and Nutrition (EPIC).
Methods:
Data from ...single 24-hour dietary recall interviews collected through a highly standardised computer-based program (EPIC-SOFT) in 27 redefined centres in 10 European countries between 1995 and 2000. From a total random sample of 36 900, 22 924 women and 13 031 men were selected after exclusion of subjects under 35 and over 74 years of age.
Results:
A high total consumption of dairy products was reported in most of the centres in Spain and in the UK cohort sampled from the general population, as well as in the Dutch, Swedish and Danish centres. A somewhat low consumption was reported in the Greek centre and in some of the Italian centres (Ragusa and Turin). In all centres and for both sexes, milk constituted the dairy sub-group with the largest proportion (in grams) of total dairy consumption, followed by yoghurt and other fermented milk products, and cheese. Still, there was a wide range in the contributions of the different dairy sub-groups between centres. The Spanish and Nordic centres generally reported a high consumption of milk, the Swedish and Dutch centres reported a high consumption of yoghurt and other fermented milk products, whereas the highest consumption of cheese was reported in the French centres.
Conclusion:
The results demonstrate both quantitative and qualitative disparities in dairy product consumption among the EPIC centres. This offers a sound starting point for analyses of associations between dairy intake and chronic diseases such as cancer.
To describe the diversity in dietary patterns existing across centres/regions participating in the European Prospective Investigation into Cancer and Nutrition (EPIC).
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.
In total, 35 955 men and women, aged 35-74 years, participating in the EPIC nested calibration study.
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.
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.
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.
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.
Twenty-seven redefined centres in the 10 European countries participating in the EPIC study.
In total, 35 955 subjects (13 031 men and 22 924 women), aged 35-74 years, selected from the main EPIC cohort.
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, respectively, with the greatest consumption in centres in Spain and Greece and the least in the German and Dutch centres. Consumption of fatty fish reflected that of total fish. However, the greatest intake of very fatty fish was in the coastal areas of northern Europe (Denmark, Sweden and Norway) and in Germany. Consumption of fish products was greater in northern than in southern Europe, with white fish products predominating in centres in France, Italy, Spain, The Netherlands and Norway. Intake of roe and roe products was low. The highest consumption of crustacea was found in the French, Spanish and Italian centres. The number of fish types consumed was greater in southern than in northern Europe. The greatest variability in consumption by day of the week was found in the countries with the lowest fish intake.
Throughout Europe, substantial geographic variation exists in total fish intake, fish sub-groups and the number of types consumed. Day-to-day variability in consumption is also high.
To describe and compare the consumption of the main groups and sub-groups of vegetables and fruits (V&F) in men and women from the centres participating in the European Prospective Investigation into ...Cancer and Nutrition (EPIC).
Cross-sectional analysis. Dietary intake was assessed by means of a 24-hour dietary recall using computerised interview software and standardised procedures. Crude and adjusted means were computed for the main groups and sub-groups of V&F by centre, separately for men and women. Adjusted means by season, day of the week and age were estimated using weights and covariance analysis.
Twenty-seven centres in 10 European countries participating in the EPIC project.
In total, 35 955 subjects (13 031 men and 22 924 women), aged 35-74 years, randomly selected from each EPIC cohort.
The centres from southern countries had the highest consumption of V&F, while the lowest intake was seen in The Netherlands and Scandinavia for both genders. These differences were more evident for fruits, particularly citrus. However, slightly different patterns arose for some sub-groups of vegetables, such as root vegetables and cabbage. Adjustment for body mass index, physical activity, smoking habits and education did not substantially modify the mean intakes of vegetables and fruits.
Total vegetable and fruit intake follows a south-north gradient in both genders, whereas for several sub-groups of vegetables a different geographic distribution exists. Differences in mean intake of V&F by centre were not explained by lifestyle factors associated with V&F intake.
Background Differential underreporting of dietary intake by subgroups of body mass index (BMJ) will confound associations between dietary intake and BMI-related diseases. We estimated the magnitude ...of BMI-related underreporting for energy,. protein, and potassium intake for the Dutch cohorts of the European Prospective Investigation into Cancer and Nutrition (EPIC). Methods The study population consisted of 134 Dutch men and women, aged 21–71 years, who participated in a pilot of EPIC. Ratios of reported dietary intakes to biomarkers were used as measures for underreporting. Dietary intake was assessed by a food frequency questionnaire (FFQ) and repeated 24-hour dietary recalls. Biomarker for energy intake was calculated basal metabolic rate; for protein and potassium intake the biomarker was 24-hour urinary nitrogen and potassium excretion, respectively. The measures of underreporting were linearly regressed on BMJ (in kg/m2). Results Significant negative regression coefficients were observed when regressing energy ratio on BMI with adjustment for physical activity (FFQ: β = −0.04 for men, β = −0.02 for women; 24-hour recalls: β = −0.03 for men, β = −0.04 for women). In men, a significant negative regression coefficient (β = −0.03) was observed when regressing protein ratio on BMI; for the recalls however only after adjustment for age and education (β = −0.02). In women, negative regression coefficients were also obtained, but for the FFQ only after exclusion of dieting women (both FFQ and 24-hour recalls: β = −0.02). According to the recalls, but not the FFQ, a significant negative regression coefficient (β = −0.02) was observed among women when regressing potassium ratio on BMI. Conclusions In this Dutch population. BMI-dependent underreporting of 20–25% over the observed range of BMI is present for protein and energy. Further study on BMI-dependent underreporting of dietary intake in EPIC cohorts is warranted. Underreporting, body mass index, energy intake, protein intake, potassium intake, measurement error
Objective The objective of this study was to test the hypothesis whether a maternal dietary pattern is associated with the risk of spina bifida (SB) in the offspring.
Design Case–control study.
...Setting Eight clinic sites in the Netherlands, 1999–2001.
Sample A total of 50 mothers of children with SB and 81 control mothers.
Methods Maternal food intakes were obtained by food frequency questionnaires at the standardised study moment of 14 months after the birth of the index child. Principal component factor analysis (PCA) and reduced rank regression (RRR) were used to identify dietary patterns.
Main outcome measures Maternal biomarkers were used as response measures in the RRR analysis and composed of serum and red blood cell (RBC) folate, serum vitamin B12 and total plasma homocysteine. The strength of the use of the dietary pattern in association with SB risk was estimated by odds ratios and 95% CI with the highest quartiles of the dietary pattern as reference.
Results A predominantly Mediterranean dietary pattern was identified by both PCA and RRR. Those dietary patterns were highly correlated (r = 0.51, P < 0.001) and characterised by joint intakes of fruit, vegetables, vegetable oil, alcohol, fish, legumes and cereals and low intakes of potatoes and sweets. We observed a significantly increased risk of SB offspring in mothers with a weak use of the Mediterranean dietary pattern, OR 2.7 (95% CI 1.2–6.1) and OR 3.5 (95% CI 1.5–7.9). The Mediterranean dietary pattern was correlated with higher levels of serum and RBC folate, serum vitamin B12 and lower plasma homocysteine.
Conclusion The Mediterranean dietary pattern seems to be associated with reduction in the risk of offspring being affected by SB.
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