Circulating 25-Hydroxyvitamin D Concentration and Risk of Breast, Prostate, and Colorectal Cancers: The Melbourne Collaborative Cohort Study

Abstract

The role of vitamin D in cancer risk remains controversial, and limited data exist on associations between vitamin D and subtypes of specific cancers. We investigated associations between circulating 25-hydroxyvitamin D (25(OH)D) and risk of colorectal, breast, and prostate cancers, including subtypes. A case-cohort study within the Melbourne Collaborative Cohort Study included 547 colorectal, 634 breast, and 824 prostate cancers, and a sex-stratified random sample of participants (n = 2,996). Concentration of 25(OH)D in baseline-dried blood spots was measured using LC-MS/MS. Cox regression yielded adjusted HRs and 95% confidence intervals (CI) for each cancer in relation to plasma-equivalent 25(OH)D concentration. Associations by stage and BRAF/KRAS status for colorectal cancer, estrogen receptor status for breast cancer, and aggressiveness for prostate cancer were examined in competing risks models. 25(OH)D concentrations were inversely associated with risk of colorectal cancer [highest vs. lowest 25(OH)D quintile: HR, 0.71; 95% confidence interval (CI), 0.51-0.98], which was limited to women (HR, 0.52; 95% CI, 0.33-0.82). Circulating 25(OH)D was also inversely associated with BRAF V600E-positive colorectal cancer (per 25 nmol/L increment: HR, 0.71; 95% CI, 0.50-1.01). There were no inverse associations with breast cancer (HR, 0.98; 95% CI, 0.70-1.36) or prostate cancer (HR, 1.11; 95% CI, 0.82-1.48). Circulating 25(OH)D concentration was inversely associated with colorectal cancer risk for women, but not with risk of breast cancer or prostate cancer. Vitamin D might play a role in preventing colorectal cancer. Further studies are required to confirm whether vitamin D is associated with specific tumor subtypes.