Objectives. To examine the sex difference in the prevalence and severity of lower urinary tract symptoms in Japanese men and women.

Methods. Of 970 individuals who attended the public lectures by urologists and a famous veterinarian that were organized as a public service of the 88th Annual Meeting of the Japanese Urological Association (June 2000, Sapporo, Japan), 677 (70%) completed the self-administered International Prostate Symptom Score (IPSS) questionnaire. The scores of 653 attendees aged 30 to 79 years (446 men, mean age 67.5 and 207 women, mean age 60.7) were the basis of this study.

Results. A significant age-related increase in IPSS and quality-of-life score was observed in both men and women. The ratio of moderate (IPSS 8 to 19) to severe (IPSS 20 or greater) symptoms in the 50s, 60s, and 70s was 52%, 72%, and 80% in men and 27%, 36%, and 55% in women, respectively. Additional analysis in each decade showed that at age 50 years and older the total score and voiding symptom score of IPSS, as well as the quality-of-life score, were significantly greater in men than in women.

Conclusions. The total IPSS and quality-of-life score correlated highly with age in both sexes. At the age of 50 years and older, men had severer voiding symptoms than did women. Although the age-related changes in bladder function predispose both men and women equally to lower urinary tract symptoms, the higher incidence of bladder outlet obstruction in men having a prostate may have a significant influence on the higher voiding symptom score in men.