Association of lower urinary tract symptoms with sexual dysfunction: a cross-cultural study between Japanese and American men with localized prostate cancer

OBJECTIVE To assess the association of lower urinary tract symptoms (LUTS) with sexual function, and estimate the correlates of LUTS among Japanese and American men with localized prostate cancer. PATIENTS AND METHODS In all, 343 Japanese men and 307 American men with prostate cancer were enrolled in the study. Sexual function and sexual bother were measured separately with the University of California-Los Angeles Prostate Cancer Index and obstructive/irritative voiding symptoms were measured with the American Urological Association Symptom Index (AUA SI). RESULTS Japanese men had worse sexual function scores than the American men before treatment, whereas no differences were reported between Japanese and American men in sexual bother scores. Japanese and American men also did not differ meaningfully in AUA SI. However, those with moderate to severe LUTS reported significantly worse sexual bother scores than those with mild symptoms in both Japanese and American men (P = 0.004 and < 0.001, respectively). The Japanese men were more likely to have LUTS than were American men (odds ratio 1.60, P = 0.029). Age and sexual function were highly associated with LUTS (odds ratio 1.35, P = 0.027; and 0.652, P = 0.001, respectively). The comorbidity count was independently associated with worse urinary symptoms (odds ratio 1.23, P = 0.015). CONCLUSIONS We posit that cultural differences in the meaning or salience of sexual functioning, and the interpretation of the questionnaire in quality-of-life surveys, might explain the different profiles in the association of LUTS with sexual activity in Japanese and American men with localized prostate cancer.