Null association between vitamin D and PSA levels among black men in a vitamin D supplementation trial.

BACKGROUND Black men exhibit a high prevalence of vitamin D deficiency as well as a higher incidence of prostate cancer and higher mortality rates from prostate cancer than Whites. There are few data about the effect of vitamin D3 (cholecalciferol) supplementation on prostate-specific antigen (PSA) in healthy Black men. METHODS During three winters from 2007 to 2010, 105 Black men (median age, 48.9 years) of Boston, MA were randomized into a four-arm, double-blind trial for 3 months of placebo, 1,000, 2,000, or 4,000 U of vitamin D3. At baseline and 3 months, free and total PSA was measured. RESULTS With vitamin D supplementation, no significant differences in free and total PSA were observed; free PSA, -0.0004 ng/mL (P = 0.94) and total PSA, -0.004 ng/mL (P = 0.92) for each additional 1,000 U/d of vitamin D3. CONCLUSION Within an unselected population of healthy Black men without a cancer diagnosis, we found no effect of vitamin D supplementation on free or total PSA. IMPACT These findings support prior findings of no change in PSA with vitamin D supplementation and emphasize the need for new methods to assess the influence of vitamin D supplementation on prostate cancer prevention.