Correlates of circulating 25-hydroxyvitamin D: Cohort Consortium Vitamin D Pooling Project of Rarer Cancers.

Low vitamin D status is common globally and is associated with multiple disease outcomes. Understanding the correlates of vitamin D status will help guide clinical practice, research, and interpretation of studies. Correlates of circulating 25-hydroxyvitamin D (25(OH)D) concentrations measured in a single laboratory were examined in 4,723 cancer-free men and women from 10 cohorts participating in the Cohort Consortium Vitamin D Pooling Project of Rarer Cancers, which covers a worldwide geographic area. Demographic and lifestyle characteristics were examined in relation to 25(OH)D using stepwise linear regression and polytomous logistic regression. The prevalence of 25(OH)D concentrations less than 25 nmol/L ranged from 3% to 36% across cohorts, and the prevalence of 25(OH)D concentrations less than 50 nmol/L ranged from 29% to 82%. Seasonal differences in circulating 25(OH)D were most marked among whites from northern latitudes. Statistically significant positive correlates of 25(OH)D included male sex, summer blood draw, vigorous physical activity, vitamin D intake, fish intake, multivitamin use, and calcium supplement use. Significant inverse correlates were body mass index, winter and spring blood draw, history of diabetes, sedentary behavior, smoking, and black race/ethnicity. Correlates varied somewhat within season, race/ethnicity, and sex. These findings help identify persons at risk for low vitamin D status for both clinical and research purposes.

Flavonoid intake and risk of pancreatic cancer in male smokers (Finland).

Extending research on the protective effect of flavonoids in cell culture and animal studies, we examined the association between consumption of flavonoids and flavonoid-rich foods and development of exocrine pancreatic cancer within the alpha-Tocopherol, beta-Carotene Cancer Prevention Study cohort. Of the 27,111 healthy male smokers (50-69 years) who completed a self-administered dietary questionnaire at baseline, 306 developed exocrine pancreatic cancer during follow-up (1985-2004; median, 16.1 years). Intakes of total flavonoids, three flavonoid subgroups, seven individual flavonoids, and flavonoid-rich foods were estimated from a validated food frequency questionnaire. Hazard ratios and 95% confidence intervals were estimated using Cox proportional hazards models. Overall, flavonoid intake was not significantly associated with pancreatic cancer. However, in stratified analysis, greater total flavonoid intake was associated with decreased pancreatic cancer risk in participants randomized during the trial to placebo (fourth versus first quartile: hazard ratio, 0.36; 95% confidence interval, 0.17-0.78; P trend = 0.009) and not to supplemental alpha-tocopherol (50 mg/d) and/or beta-carotene (20 mg/d; P interaction = 0.002). Similar patterns and significant interactions were observed for flavonols, flavan-3-ols, kaempferol, quercetin, catechin, and epicatechin. Our data suggest that a flavonoid-rich diet may decrease pancreatic cancer risk in male smokers not consuming supplemental alpha-tocopherol and/or beta-carotene.