Frequent Sex May Reduce Prostate-Cancer
Risk, Study Shows
Frequent sexual activity may reduce a man's risk of prostate cancer, according to a study in the April 7 Journal of the American Medical Association.
The cancer risk in men who reported more than 20 monthly ejaculations was 33 percent less than that of other men, the Harvard University study showed. Elevated testosterone has been tied to both a high sex drive and prostate cancer, which had led scientists to propose a link between cancer and sexual activity.
More research may help determine how sex might be protecting some men from prostate cancer, the investigators said. The results shouldn't be used to encourage intensified sexual activity, defined as ejaculation from intercourse, masturbation or during sleep, they said.
``Men worry that by being very active, they may put themselves at increased risk,'' said Michael F. Leitzmann, the lead researcher now at the National Cancer Institute. ``Looking at the data in a little bit more detail, our findings suggest that ejaculation may even be associated with a slight decrease in prostate cancer risk.''
Researchers surveyed almost 30,000 health professionals, 1,449 of whom developed prostate cancer, and found an active sex life wasn't linked to a higher cancer risk in most men.
There are several ways in which frequent ejaculations may protect against prostate cancer, the researchers said. The activity may flush out a buildup of toxins in the prostate, lessen development of tiny crystals linked to some cancers, and improve the immune system's response to cancer, Leitzmann said.
How It May WorkEjaculation also may release psychological tension, quieting central nervous system activity that may contribute to prostate- cell division and cancer growth, the researchers said.
The scientists downplayed results showing frequent ejaculation appeared to reduce cancer risk because only 7 percent of men fell into the group reporting the most activity and just 59 of them developed prostate cancer, Leitzmann said in a telephone interview.
Almost all the previous research showed sexual activity increased cancer risk, he said. Those studies may have been biased because researchers asked patients to recall activities that occurred years earlier, before they were diagnosed with cancer and received treatment, which may interfere with sexual activity, he said.
``What we can say is that this hormonal hypothesis needs to be re-evaluated,'' said Leitzmann, who led the study when he was a post-doctoral student at Harvard. ``It would be good for future research to focus on different biological mechanisms.''
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