7 research outputs found
Reproducibility and relative validity of dietary glycaemic index and glycaemic load assessed by the food-frequency questionnaire used in the Dutch cohorts of the European Prospective Investigation into Cancer and Nutrition
Dietary reporting errors on 24 h recalls and dietary questionnaires are associated with BMI across six European countries as evaluated with recovery biomarkers for protein and potassium intake
Whether there are differences between countries in the validity of
self-reported diet in relation to BMI, as evaluated using recovery
biomarkers, is not well understood. We aimed to evaluate BMI-related
reporting errors on 24 h dietary recalls (24-HDR) and on dietary
questionnaires (DQ) using biomarkers for protein and K intake and
whether the BMI effect differs between six European countries. Between
1995 and 1999, 1086 men and women participating in the European
Prospective Investigation into Cancer and Nutrition completed a single
24-HDR, a DQ and one 24 h urine collection. In regression analysis,
controlling for age, sex, education and country, each unit (1 kg/m(2))
increase in BMI predicted an approximately 1.7 and 1.3% increase in
protein under-reporting on 24-HDR and DQ, respectively (both P <
0.0001). Exclusion of individuals who probably misreported energy intake
attenuated BMI-related bias on both instruments. The BMI effect on
protein under-reporting did not differ for men and women and neither
between countries on both instruments as tested by interaction (all P >
0.15). In women, but not in men, the DQ yielded higher mean intakes of
protein that were closer to the biomarker-based measurements across BMI
groups when compared with 24-HDR. Results for K were similar to those of
protein, although BMI-related under-reporting of K was of a smaller
magnitude, suggesting differential misreporting of foods.
Under-reporting of protein and K appears to be predicted by BMI, but
this effect may be driven by ‘low-energy reporters’. The BMI effect on
under-reporting seems to be the same across countries
Dietary carbohydrates, glycemic index, glycemic load, and endometrial cancer risk within the European Prospective Investigation into Cancer and Nutrition Cohort
The associations of dietary total carbohydrates, overall glycemic index, total dietary glycemic load, total sugars, total starch, and total fiber with endometrial cancer risk were analyzed among 288,428 women in the European Prospective Investigation into Cancer and Nutrition cohort (1992-2004), including 710 incident cases diagnosed during a mean 6.4 years of follow-up. Cox proportional hazards models were used to estimate relative risks and 95% confidence intervals. There were no statistically significant associations with endometrial cancer risk for increasing quartile intakes of any of the exposure variables. However, in continuous models calibrated by using 24-hour recall values, the multivariable relative risks were 1.61 (95% confidence interval: 1.06, 2.45) per 100 g/day of total carbohydrates, 1.40 (95% confidence interval: 0.99, 1.99) per 50 units/day of total dietary glycemic load, and 1.36 (95% confidence interval: 1.05, 1.76) per 50 g/day of total sugars. These associations were stronger among women who had never used postmenopausal hormone therapy compared with ever users (total carbohydrates P-heterogeneity = 0.04). Data suggest no association of overall glycemic index, total starch, and total fiber with risk, and a possible modest positive association of total carbohydrates, total dietary glycemic load, and total sugars with risk, particularly among never users of hormone replacement therapy
Methodological Challenges In the Application of the Glycemic Index In Epidemiological Studies Using Data from the European Prospective Investigation into Cancer and Nutrition
Associations between the glycemic index (GI) or glycemic load (GL) and diseases are heterogeneous in epidemiological studies. Differences in assigning GI values to food items may contribute to this inconsistency. Our objective was to address methodological issues related to the use of current GI and GL values in epidemiological studies. We performed ecological comparison and correlation studies by calculating dietary GI and GL from country-specific dietary questionnaires (DO) from 422,837 participants from 9 countries participating in the European Prospective Investigation into Cancer and Nutrition study and single standardized 24-h dietary recalls (24-HDR) obtained from a representative sample (n = 33,404) using mainly Foster Powell's international table as a reference source. Further, 2 inter-rater and 1 inter-method comparison were conducted, comparing DO GI values assigned by independent groups with values linked by us. The ecological correlation between DO and 24-HDR was good for GL (overall r = 0.76; P 0.80). A more consistent methodology to attribute GI values to foods and validated DO is needed to derive meaningful GI/GL estimates for nutritional epidemiology. J. Nutr. 139: 568-575, 2009