Cancer Research Lab

High serum selenium levels before diagnosis are not associated with prostate cancer risk, according to findings published in the January issue of the American Journal of Clinical Nutrition. However, high selenium levels may be protective in certain subgroups.

“Selenium is a potential chemopreventive agent against prostate cancer, whose chemoprotective effects are possibly mediated through the antioxidative properties of selenoenzymes,” Dr. Ulrike Peters, of Fred Hutchinson Cancer Research Center, Seattle, and colleagues write.

The researchers conducted a nested case-control study with subjects from the screening arm of the Prostate, Lung, Cholesterol, and Ovarian Cancer Screening Trial to examine the association between serum selenium, prostate cancer risk, as well as the effects of other antioxidants and tobacco use.

The team compared serum selenium in prospectively collected samples from 724 subjects with incident prostate cancer and 879 controls. All participants completed a questionnaire at enrollment regarding age, ethnicity, education, occupation, smoking history, history of cancer and other diseases, use of selected drugs, recent history of screening exams, and prostate related health factors.

A 137-item food-frequency questionnaire was used to assess usual dietary intake over the 12 months before enrollment. The patients were followed for up to 8 years.

Overall, the researchers found no association between serum selenium and prostate cancer risk. However, higher serum selenium was inversely associated with prostate cancer in men who reported a high vitamin E intake (more than the median: 28.0 IU/d) and those taking multivitamins. There was also an inverse association between high selenium levels and prostate cancer risk in smokers.