Elevated Risk for Prostate Cancer Found With Vitamin E Supplementation
Abstract and Introduction
Clinicians should counsel older men about vitamin E use.
Basic science and epidemiologic data have suggested that vitamin E and selenium supplementation lower risk for prostate cancer. However, when early results from a large controlled trial of vitamin E supplementation showed no fewer cases of — and a possible excess risk for — prostate cancer after 3 years, supplementation was halted (JW Gen Med Jan 15 2009). This new report includes data from 3 additional years of follow-up.
Originally, the 35,533 men were randomized to daily selenium (200 µg) plus vitamin E placebo, vitamin E (400 IU) plus selenium placebo, both selenium and vitamin E, or double placebo. Participants (age, ≥50 for blacks, ≥55 for whites) had prostate-specific antigen levels ≤4 ng/mL and normal digital rectal exams. Nearly 1800 incident cases of prostate cancer were diagnosed initially, and an additional 521 cases were diagnosed during the latest follow-up. The overall risk for prostate cancer was significantly elevated (by 17%) in the vitamin E group, with no significant difference in the other treatment groups. Excess risk was similar for patients with Gleason scores ≥7 and for patients with scores <7, but only the overall results achieved statistical significance.
These results confirm what was suspected in the first analysis: Vitamin E raised risk for prostate cancer, and that risk was mitigated by selenium supplementation. Because many older men take vitamin E for a wide range of unsubstantiated benefits, clinicians should ask about and counsel them about vitamin E use.
Klein EA et al. Vitamin E and the risk of prostate cancer: The Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA 2011 Oct 12; 306:1549.