Frequent ejaculation is not associated with a higher risk for prostate cancer but may be linked to a decreased risk of the cancer.
Sexual activity has been previously believed to play a role in the development of prostate cancer. Dr Michael Leitzmann of the National Cancer Institute, Bethesda, Maryland, and colleagues, examined the association between ejaculation frequency (including sexual intercourse, nocturnal emission, and masturbation) and the risk of prostate cancer (JAMA. 2004;291: 1578-86).
The study used follow up data from the health professionals follow up study which was started in 1986 when 51 529 predominantly white, male American health professionals aged 40 to 75 years responded to a questionnaire about their medical history and known or suspected risk factors for cancer and other chronic diseases. Subsequently, follow up questionnaires were mailed every two years.
In 1992, the questionnaire included an assessment of frequency of ejaculation. About 29 000 men in the United States, aged 46 to 81 years, provided information on history of ejaculation frequency.
Ejaculation frequency was assessed by asking participants to report the average number of ejaculations they had per month during the ages of 20 to 29 years, 40 to 49 years, and during the past year. Among the participants, there were 1449 new cases of total prostate cancer, 953 organ confined cases, and 147 advanced cases of prostate cancer.
Most categories of ejaculation frequency were unrelated to risk of prostate cancer. However, high frequency was related to decreased risk of total prostate cancer.
The multivariate relative risks for men reporting 21 or more ejaculations a month compared with men reporting four to seven ejaculations a month were 0.89 (95% confidence interval 0.73 to 1.10) at ages 20 to 29 years; 0.68 (0.53 to 0.86) at ages 40 to 49; 0.49 (0.27 to 0.88) for the previous year; and 0.67 (0.51 to 0.89) averaged across a lifetime. Similar associations were observed for organ confined prostate cancer.