Vitamin D compounds have been shown to inhibit prostate tumorigenesis experimentally, but based on the small number of epidemiological studies conducted to date, the relation between vitamin D status and prostate cancer risk remains unclear. We investigated the association between 25-hydroxyvitamin D [25(OH)D] and prostate cancer in a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study of 50-69 year old Finnish men. To 1,000 cases diagnosed during up to 20 years of follow-up, we matched 1,000 controls on age (within 1 year) and baseline blood collection date (within 30 days). Serum samples were assayed for 25(OH)D using the DiaSorin LIAISON 25(OH)D method (intra-batch and inter-batch CVs, 10.5% and 12.3%), and conditional multivariate logistic regression models estimated odds ratios (OR) and 95% confidence intervals (CI) for the prostate cancer-25(OH)D association, conditioned on the matching factors and adjusted for body mass index, residence, benign prostatic hyperplasia, and the trial supplements. 25(OH)D concentrations were categorized according to quintiles based on control cut-points of <18.6, −28.3, −39.7, >53.3 nmol/L. ORs (95% CIs) for Q1-Q5 were 1.00 (reference), 1.39 (1.04-1.86), 1.54 (1.14-2.08), 1.20 (0.88-1.62), and 1.41 (1.03-1.93)(p-trend=0.06). These findings were similar for subgroups of age, season of blood draw, time from blood draw to diagnosis, body mass index, vitamin D intake, and disease stage. Analyses of 25(OH)D based on clinically-defined categories, season-adjusted (by regression residual method), and season-specific cut-points yielded similar results. Our findings suggest that men with lower serum 25(OH)D levels may be at lower risk of developing prostate cancer compared to men with higher levels.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2796.