Longitudinal changes in prostate volume in a community-based cohort study of middle-aged and elderly men in rural China

Background Prostate volume (PV) and its change rate are important for the progression of prostate disease, but studies on their estimates are inconsistent. Objectives To investigate whether age, prostate-specific antigen (PSA), and other specific characteristics are associated with PV and its change rate. Materials and Methods A community-based cohort study was conducted in a rural area of China among male residents aged 40-80 years. PV was estimated at baseline and at 4 years of follow-up by trans-abdominal ultrasound. Annual PV change rate (PVCR) was calculated as change in volume divided by time interval. Baseline characteristics, including age, serum PSA, and hormones, were evaluated. And their relationships with PV or PVCR were assessed with Pearson correlation and multivariate linear regression analyses. Results Totally, 462 participants completed the follow-up with baseline PV (PV0) of 15.6 +/- 5.5 ml. PV0 was highly correlated with age and PSA in pairwise correlations (Pearson r = 0.35 and 0.34, respectively, p < 0.01). Multivariate linear regression showed similar associations that PV0 tended to increase with age and PSA. The average PVCR was 0.7 +/- 1.8 ml/year. In pairwise correlations, PVCR was inversely correlated with PV0 and positively correlated with PSA, while it was not significantly related to baseline age. Linear regression of PVCR on age and PSA in groups classified by PV0 quartile showed that age was not a significant estimator of PVCR, whereas PSA was. In each PV0 group, PVCR tended to increase with PSA. Discussion and Conclusion PV was positively associated with age and PSA, and it tended to grow faster in men with smaller baseline PV and higher PSA. PSA can be a valuable parameter for estimating both the size and the growth speed of prostate. Although age is associated with prostate enlargement, it does not appear to be related to the longitudinal change rate of PV.