Purpose: We examined risk factors for incident symptomatic benign prostate hyperplasia in 5,667 Prostate Cancer Prevention Trial placebo arm participants who were free of benign prostatic hyperplasia at baseline.
Materials and methods: During 7 years benign prostatic hyperplasia symptoms were assessed annually using the International Prostate Symptom Score and benign prostatic hyperplasia treatment was assessed quarterly by structured interview. Total benign prostatic hyperplasia was defined as receipt of treatment or report of 2 International Prostate Symptom Score values greater than 14. Severe benign prostatic hyperplasia was defined as treatment or 2 International Prostate Symptom Score values of 20 or greater. Weight and body circumferences were measured by trained staff and demographic health related characteristics were collected by questionnaire. Cox proportional hazards models were used to calculate the covariate adjusted relative hazards of benign prostatic hyperplasia developing.
Results: The incidence of total benign prostatic hyperplasia was 34.4 per 1,000 person-years. The risk of total benign prostatic hyperplasia increased 4% (p <0.001) with each additional year of age. Risks for total benign prostatic hyperplasia were 41% higher for black (p <0.03) and Hispanic men (p <0.06) compared to white men, and for severe benign prostatic hyperplasia these increases were 68% (p <0.01) and 59% (p <0.03), respectively. Each 0.05 increase in waist-to-hip ratio (a measure of abdominal obesity) was associated with a 10% increased risk of total (p <0.003) and severe (p <0.02) benign prostatic hyperplasia. Neither smoking nor physical activity was associated with risk.
Conclusions: Black race, Hispanic ethnicity and obesity, particularly abdominal obesity, are associated with increased benign prostatic hyperplasia risk. Weight loss may be helpful for the treatment or prevention of benign prostatic hyperplasia.