Components of the metabolic syndrome—risk factors for the development of benign prostatic hyperplasia

The purpose of the present study was to perform a BPH risk factor analysis in men, relating the prostate gland volume to components of the metabolic syndrome and to identify clues to the etiology of BPH. Our material comprised a consecutive series of 158 patients with lower urinary tract symptoms with or without manifestations of the metabolic syndrome. In this group, the measured volume of the prostate was related consecutively to potential risk factors. The diagnoses atherosclerosis, non-insulin-dependent diabetes mellitus (NIDDM) and treated hypertension were obtained from the patient's medical history. Data on blood pressure, waist and hip measure, body height and weight were collected and body mass index (BMI) and waist/hip ratio (WHR) were calculated. Blood samples were drawn from fasting patients to determine insulin, cholesterol, triglycerides, HDL and LDL-cholesterol, uric acid and ALAT. The prostate gland volume was determined using ultrasound. Our results show that there was a larger prostate gland in men with NIDDM (P=0.0058), treated hypertension (P=0.0317), obesity (P<0.0001), low HDL-cholesterol levels (P=0.0132) and high insulin levels (P<0.0001) than in men without these conditions. The prostate gland volume correlated positively with the systolic blood pressure (r(s)=0.17; P=0.03), obesity (r(s)=0.34; P<0.0001) and fasting insulin (r(s)=0.38; P<0.0001) and negatively with HDL-cholesterol (r(s)=-0.22; P=0.009). On the basis of our findings, we concluded that NIDDM, treated hypertension, obesity, low HDL-cholesterol levels and high insulin levels constitute risk factors for the development of BPH. The results suggest that BPH is a facet of the metabolic syndrome and that BPH patients may share the same metabolic abnormality of a defective insulin-mediated glucose uptake and secondary hyperinsulinemia as patients with the metabolic syndrome. The findings generate a hypothesis of a causal relationship between high insulin levels and the development of BPH. In a clinical setting, the findings of the present report suggest that, in any patient presenting with BPH, the possible presence of NIDDM, hypertension, obesity, high insulin and low HDL-cholesterol levels should be considered. Conversely, in patients suffering from these conditions, the possibility of a clinically important BPH should be kept in mind.