Selenium and Sex Steroid Hormones in a U.S. Nationally Representative Sample of Men: A Role for the Link between Selenium and Estradiol in Prostate Carcinogenesis?

BACKGROUND

Given the recent findings from pooled studies about a potential inverse association between selenium levels and prostate cancer risk, this cross-sectional study aimed to investigate the association between serum selenium and serum concentrations of sex steroid hormones including estradiol in a nationally representative sample of U.S. men to investigate one mechanism by which selenium may influence prostate cancer risk.

METHODS

The study included 1,420 men ages 20 years or older who participated in the Third National Health and Nutrition Examination Survey between 1988 and 1994. We calculated 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, and compared them across quartiles of serum selenium.

RESULTS

Adjusting for age, race/ethnicity, smoking status, serum cotinine, household income, physical activity, alcohol consumption, and percent body fat, mean total estradiol [e.g., Q1, 38.00 pg/mL (95% confidence interval (CI), 36.03-40.08) vs. Q4, 35.29 pg/mL (95% CI, 33.53-37.14); = 0.050] and free estradiol [e.g., Q1, 0.96 pg/mL (95% CI, 0.92-1.01) vs. Q4, 0.90 (95% CI, 0.85-0.95); = 0.065] concentrations decreased over quartiles of selenium. Stratification by smoking and alcohol consumption, showed that the latter observation was stronger for never smokers ( = 0.073) and those with limited alcohol intake ( = 0.017). No associations were observed for the other sex steroid hormones studied.

CONCLUSIONS

Our findings suggests that a possible mechanism by which selenium may be protective for prostate cancer is related to estrogen.

IMPACT

Further studies of longitudinal measurements of serum and toenail selenium in relation to serum measurements of sex steroid hormones are needed.