Japanese men have smaller prostate volumes but comparable urinary flow rates relative to American men: results of community based studies in 2 countries.

Abstract

We compared prostate volume and peak urinary flow rate in Japanese and American men 40 to 79 years old. Prostate volume and peak urinary flow rate were measured in eligible Japanese men and results were compared to those of a randomly selected American cohort. Mean prostate volume plus or minus standard deviation averaged 20.3 +/- 10.6 ml. in Japanese and 29.6 +/- 13.4 ml. in American men, while predicted cross-sectional increases with age decade were 1.5 and 5.5 ml., respectively. Peak urinary flow rate was higher but the decrease with increasing age was greater in Japanese men. Prostate volume is larger and the increase with age is more pronounced in American than in Japanese men. However, Japanese men may have a higher peak urinary flow rate and greater cross-sectional decrease with age.