Serum sex hormones and measures of benign prostatic hyperplasia

BACKGROUND. Despite biologic plausibility, the associations between sex hormones and measures of benign prostatic hyperplasia (BPH) have not been consistently reported. METHODS. Subjects were randomly selected from the Olmsted County, MN population (n, 320; median age, 60.9 years) and followed biennially since 1990. In 2002, surrogate measures of BPH were assessed from an approximation of the American Urological Association Symptom Index (AUASI), Peak urinary flow rates (Q_max), and a transrectal ultrasound assessment of prostate volume. Serum levels of prostate specific antigen (PSA), testosterone, bioavailable testosterone, and estradiol were also measured. RESULTS. Bioavailable testosterone levels declined with increasing cross-sectional age from 53.8, 50.2, to 41.2 ng/dl (P = 0.001) in men aged <60, 60-69, and >69 years, respectively, and the estradiol/bioavailable testosterone ratio increased from 0.042, 0.044, to 0.050 (P = 0.04). Among men with bioavailable testosterone above the median, estradiol levels had a dose response relationship with prostate size. Among men with bioavailable testosterone level ≤ the median, however, there was no association between estradiol level and prostate volume CONCLUSIONS. While cross-sectional, these findings suggest a more complex relationship between sex steroids and prostate volume in older men than simple independent effects.