Van Hemelrijck M, et al. - In this cross-sectional study including 1,420 men aged 20 years or older who were part of the Third National Health and Nutrition Examination Survey, researchers examined the link between serum selenium and serum concentrations of sex steroid hormones (including estradiol) to assess how selenium may impact prostate cancer risk. In this study performed in a nationally representative sample of US men, they compared age/race-ethnicity-adjusted and multivariable-adjusted geometric mean serum concentrations of total and estimated free testosterone and estradiol, androstanediol glucuronide, and sex hormone binding globulin across quartiles of serum selenium. Findings revealed mean total estradiol and free estradiol concentrations decreased over quartiles of selenium, after adjusting for age, race/ethnicity, smoking status, serum cotinine, household income, physical activity, alcohol consumption, and percent body fat. Overall, findings indicated that a possible mechanism by which selenium may be protective for prostate cancer is associated with estrogen.