April 6, 2004 -- Frequent ejaculation, whether it happens
during sexual intercourse, masturbation, or a dream, isn't
likely to increase men's risk of prostate cancer. In fact, new
research suggests it may have the opposite effect and help protect the prostate.
Researchers say it's too soon to recommend that men change
their sexual habits in an attempt to lower their prostate cancer risk. However, the study
raises interesting questions about the role of ejaculation and sexual behavior
in the development of prostate cancer.
Previous studies have linked frequent sexual activity to a
higher risk of prostate cancer, but this new, large study found ejaculation
frequency was not associated with prostate cancer risk except in the highest
category. Men who ejaculated most often actually had a 33% lower lifetime risk
of prostate cancer, and this relationship grew stronger as men grew older.
For example, men who reported 21 or more ejaculations per month
in their 40s had a 32% lower risk of prostate cancer later in life compared
with those who reported between four and seven ejaculations per month. Men who
reported more than 21 monthly ejaculations in the previous year had a 51% lower
risk of prostate cancer.
Overall, an average of 21 or more ejaculations a month during a
man's lifetime decreased the risk of prostate cancer later in life by 33%. And
each increase of three ejaculations per week during a man's lifetime was
associated with a 15% reduction in prostate cancer risk.
The findings, published in the April 7 issue of The Journal
of the American Medical Association, are based on data collected from
nearly 30,000 predominately white men aged 46 to 81.
At the start of the study, men provided information on
ejaculation frequency in their 20s, 40s, and in the previous year (1991).
Ejaculation frequency included sexual intercourse, masturbation, and nighttime
ejaculations that can occur during sleep. The men were then monitored for eight
Researchers found most categories of ejaculation frequency were
unrelated to prostate cancer risk. But when they looked at men in the highest
category of ejaculation frequency, they found evidence of a protective
"When you look at the data in a little bit more detail, you do
see that not only is there not an increased risk, but there is potentially even
the possibility of a slight decrease in risk with high ejaculation frequency,"
says researcher Michael Leitzmann, MD, an investigator at the National Cancer
Institute in Bethesda, Md. Leitzmann conducted the research during a
post-doctoral fellowship at Harvard University.
Leitzmann says researchers suspected that ejaculation frequency
might be a marker of a healthier, more active lifestyle. But when they
accounted for diet, exercise, and other risk factors
for prostate cancer, the link between frequent ejaculation and lower prostate
cancer risk remained.