Diabetes prevalence is associated with serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in US middle-aged Caucasian men and women: A cross-sectional analysis within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial

Hypovitaminosis D may be associated with diabetes, hypertension and CHD. However, because studies examining the associations of all three chronic conditions with circulating 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D) are limited, we examined these associations in the US Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial (n 2465). Caucasian PLCO participants selected as controls in previous nested case-control studies of 25(OH)D and 1,25(OH)2D were included in this analysis. Diabetes, CHD and hypertension prevalence, risk factors for these conditions and intake of vitamin D and Ca were collected from a baseline questionnaire. Results indicated that serum levels of 25(OH)D were low ( < 50 nmol/l) in 29 % and very low ( < 37 nmol/l) in 11 % of subjects. The prevalence of diabetes, hypertension and CHD was 7, 30 and 10 %, respectively. After adjustment for confounding by sex, geographical location, educational level, smoking history, BMI, physical activity, total dietary energy and vitamin D and Ca intake, only diabetes was significantly associated with lower 25(OH)D and 1,25(OH)2D levels. Caucasians who had 25(OH)D ≥ 80 nmol/l were half as likely to have diabetes (OR 0•5 (95 % CI 0•3, 0•9)) compared with those who had 25(OH)D < 37 nmol/l. Those in the highest quartile of 1,25(OH)2D ( ≥ 103 pmol/l) were less than half as likely to have diabetes (OR 0•3 (95 % CI 0•1, 0•7)) than those in the lowest quartile ( < 72 pmol/l). In conclusion, the independent associations of 25(OH)D and 1,25(OH)2D with diabetes prevalence in a large population are new findings, and thus warrant confirmation in larger, prospective studies.