April 6, 2004 -- High ejaculatory frequency is not associated with an increased risk of prostate cancer and may even be protective, according to the results of a prospective study published in the April 7 issue of The Journal of the American Medical Association.
"Sexual activity has been hypothesized to play a role in the development of prostate cancer," write Michael F. Leitzmann, MD, from the National Cancer Institute in Bethesda, Maryland, and colleagues. "Given that sexual activity is common, including in older men, and that prostate cancer risk is high, any association between these factors would have clinical and public health relevance."
In 1992, a total of 29,342 men from the U.S. Health Professionals Follow-up Study completed a self-administered questionnaire on frequency of ejaculation, including sexual intercourse, nocturnal emission, and masturbation. Participants were asked to report the average number of ejaculations per month during the ages of 20 to 29 years, 40 to 49 years, and during the past year (1991). Age range was 46 to 81 years. Every two years from Feb. 1, 1992, through Jan. 31, 2000, participants completed follow-up questionnaires.
During 222,426 person-years of follow-up, there were 1,449 new cases of total prostate cancer, including 953 organ-confined cases and 147 advanced cases. Although most categories of ejaculation frequency were unrelated to risk of prostate cancer, high ejaculation frequency was related to decreased risk of total prostate cancer. Compared with men reporting four to seven ejaculations per month averaged across a lifetime, men who reported 21 or more ejaculations per month had a multivariate relative risk of prostate cancer of 0.67 (95% confidence interval, 0.51 - 0.89).
Study limitations include possible avoidance of sexual activity in men with symptoms of prostate cancer, detection bias, possible confounding factors, self-reported ejaculation frequency, and lack of data during adolescence.
"In this prospective cohort study among predominantly white men, higher ejaculation frequency was not related to increased risk of prostate cancer," the authors write. "Our results suggest that high ejaculation frequency possibly may be associated with a lower risk of total and organ-confined prostate cancer. These associations were not explained by potential risk factors for prostate cancer, such as age, family history of prostate cancer, history of syphilis or gonorrhea, smoking, and diet."
The National Institutes of Health and the National Cancer Institute supported this study.
JAMA. 2004;291:1578-1586
Reviewed by Gary D. Vogin, MD
Medscape Medical News © 2004
Cite this: Laurie Barclay. Frequent Ejaculation Not Linked to Increased Risk of Prostate Cancer - Medscape - Apr 06, 2004.
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