A case‐control study of prostatic cancer in Kyoto, Japan: Sexual risk factors

Abstract

A case‐control study on prostatic cancer was conducted in Kyoto, Japan, from 1981–1984, including 100 patients with prostatic cancer (PC) and age, hospital, and date‐of‐admission matched controls of benign prostatic hyperplasia (BPH) patients and general hospital patients. Analysis of several sexual factors obtained through a self‐administered questionnaire revealed the following observations: (1) cancer patients had fewer sex partners before marriage (relative risk, RR = 0.35; 95% confidence interval: 0.13–0.93 than the hospital controls; (2) they had more vigorous sexual activities in the third (RR = 2.89: 1.01–8.28 and fourth decades of life (RR = 2.26: 1.03–4.95) than hospital controls, but no significantly different sexual activities from controls in other decades; (3) they had less frequent orgasms (RR = 2.55; 1.11–5.83) than BPH controls or (RR = 4.96: 1.78–13.9) hospital controls, and sexual intercourse appeared to be less satisfactory (RR = 2.08: 1.05–4.13) than that of hospital controls; and (4) they had less frequent episodes of sexually transmitted diseases (RR = 0.36: 0.16–0.83) than BPH controls. Marital status, fertility, ejaculation, masturbation, nocturnal emission, contraceptive use, and wife's episodes of sexually transmitted disease were not linked to prostatic cancer risk.