Clinical, anthropometric, metabolic and insulin profile of men with fast annual growth rates of benign prostatic hyperplasia.

The purpose of this study was to test the hypothesis of a causal relationship between high insulin levels and the development of benign prostatic hyperplasia (BPH) and to determine the clinical, anthropometric, metabolic and insulin profile in men with fast-growing BPH compared with men with slow-growing BPH. The present study was designed as a risk factor analysis of BPH in which the estimated annual BPH growth rate was related to components of the metabolic syndrome. Two hundred and fifty patients referred to the Urological Section, Department of Surgery, Central Hospital, Varberg, Sweden, with lower urinary tract symptoms with or without manifestations of the metabolic syndrome were consecutively included. The prevalences of atherosclerotic disease manifestations, non-insulin-dependent diabetes mellitus (NIDDM) and treated hypertension were obtained. Data on blood pressure, waist and hip measurement, 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, total cholesterol, triglycerides, HDL and LDL cholesterol, uric acid, alanine aminotransferase (ALAT) and prostate-specific antigen (PSA). The prostate gland volume was determined using ultrasound. The median annual BPH growth rate was 1.04 ml/year. Men with fast-growing BPH had a higher prevalence of NIDDM (p = 0.023) and treated hypertension (p = 0.049). These patients were also taller (p=0.004) and more obese as measured by body weight (p<0.001), BMI (p=0.026), waist measurement (p <0.001), hip measurement (p = 0.006) and WHR (p=0.029). Moreover, they had elevated fasting plasma insulin levels (p = 0.018) and lower HDL cholesterol levels (p = 0.021) than men with slow-growing BPH. The annual BPH growth rate correlated positively with diastolic blood pressure (rs = 0.14; p = 0.009), BMI (rs = 0.24; p < 0.001) and four other expressions of obesity and fasting plasma insulin level (rs = 0.18; p = 0.008), and negatively with the HDL cholesterol level (rs = -0.22; p = 0.001). In conclusion, the data suggest that NIDDM, hypertension, tallness, obesity, high insulin and low HDL cholesterol levels constitute risk factors for the development of BPH. The results also suggest that BPH is a component of the metabolic syndrome and that BPH patients may share the same metabolic abnormality of a defective insulin-mediated glucose uptake and secondary hyperinsulinaemia, as patients with the metabolic syndrome. The findings support the hypothesis of a causal relationship between high insulin levels and the development of BPH, and give rise to a hypothesis of increased sympathetic nerve activity in men with BPH.