JAPANESE MEN HAVE SMALLER PROSTATE VOLUMES BUT COMPARABLE URINARY FLOW-RATES RELATIVE TO AMERICAN MEN - RESULTS OF COMMUNITY-BASED STUDIES IN 2 COUNTRIES

Purpose: We compared prostate volume and peak urinary flow rate in Jap anese and American men 40 to 79 years old. Materials and Methods: Pros tate volume and peak urinary flow rate were measured in eligible Japan ese men and results were compared to those of a randomly selected Amer ican cohort. Results: Mean prostate volume plus or minus standard devi ation averaged 20.3 +/- 10.6 ml. in Japanese and 29.6 +/- 13.4 ml. in American men, while predicted cross-sectional increases with age decad e were 1.5 and 5.5 ml., respectively. Peak urinary flow rate was highe r but the decrease with increasing age was greater in Japanese men. Co nclusions: Prostate volume is larger and the increase with age is more pronounced in American than in Japanese men. However, Japanese men ma y have a higher peak urinary flow rate and greater cross-sectional dec rease with age.