Serum selenium level and prostate cancer: a case-control study.

Selenium is a potential chemopreventive agent against prostate cancer. This study sought to evaluate and compare the serum selenium level in men with newly diagnosed prostate cancer and noncancerous patients. Between 2005 and 2006, this prospective case-control study was performed on patients referred to Sina and Imam University hospitals, Tehran, Iran; it included 62 men with clinicopathologically confirmed diagnosis of prostate cancer (case group) and 68 men with no detectable prostate cancer [normal digital rectal examination and prostate-specific antigen (PSA) level] or any other malignant disease (control group). The serum selenium level was assessed using Zeeman graphite furnace atomic absorption spectrometer (Varian Company, Australia). The mean serum selenium level in the case and control group was 66.3 +/- 17.7 microg/l and 77.5 +/- 22.5 microg/l, respectively (P = 0.002). Serum selenium was inversely associated with prostate cancer risk. After adjustment for age, body mass index (BMI), and smoking, the odds ratio was 0.16 and 95% confidence intervals were 0.06 to 0.47 (P trendq = 0.001) comparing the highest with the lowest tertile (> or = 89.3 microg/l). No correlation was observed between serum selenium level and age, BMI, or PSA level. In conclusion, serum selenium levels in prostate cancer cases were lower than in controls, which supports the hypothesis that selenium may protect against prostate cancer.