Insulin and free oestradiol are independent risk factors for benign prostatic hyperplasia

The aetiology of benign prostatic hyperplasia (BPH) remains unclear. The objective of the present study was to test the insulin, oestradiol and metabolic syndrome hypotheses as promoters of BPH. The design was a risk factor analysis of BPH in which the total prostate gland volume was related to endocrine and anthropometric factors. The participants studied were 184 representative men, aged 72-76 years, residing in Goteborg, Sweden. Using a multivariate analysis, BPH as measured by the total prostate gland volume correlated statistically significantly with fasting serum insulin (beta = 0.200, P = 0.028), free oestradiol (beta = 0.233, P = 0.008) and lean body mass (beta = 0.257, P = 0.034). Insulin and free oestradiol appear to be independent risk factors for BPH, confirming both the insulin and the oestradiol hypotheses. Our findings also seem to confirm the metabolic syndrome hypothesis. The metabolic syndrome and its major endocrine aberration, hyperinsulinaemia, are possible primary events in BPH. Prostate Cancer and Prostatic Diseases (2009) 12, 160-165; doi:10.1038/pcan.2008.50; published online 30 September 2008