By Ed Edelson
HealthDay Reporter by Ed Edelson
healthday Reporter Tue Dec 8, 11:48 pm ET
TUESDAY, Dec. 8 (HealthDay News) -- Having a few more cups of coffee and
running that extra mile each day can reduce a man's risk of dying of prostate
cancer, two studies indicate.
The case for coffee and physical activity as prostate cancer preventatives is
far from proven, according to the research reported Tuesday at an American
Association for Cancer Research meeting in Houston. But data from the Health
Professionals Follow-Up Study show a clear association with both daily
activities.
"I wouldn't recommend that people change their coffee-drinking habits based on
this study," said Kathryn M. Wilson, a research fellow in epidemiology at the
Harvard School of Public Health, and lead author of one report. "But if you
like coffee, there is no compelling reason to cut back at this point."
Her data on the nearly 50,000 men in the study showed how common a diagnosis of
prostate cancer has become since widespread screening began. In the 20 years
from 1986 to 2006, 4,975 cases of prostate cancer were diagnosed, affecting
just about 10 percent of the men in the study.
But only 846 of those cancers were life-threatening, because they had spread
beyond the prostate gland or were growing aggressively, Wilson said. And while
the study found just a weak relationship between consumption of six or more
cups of coffee a day and a reduced risk of all forms of prostate cancer (down
about 19 percent), the reduction for the aggressive form was much more marked
-- 41 percent.
And there was a clear relationship between the amount of coffee consumed and
prostate cancer risk, Wilson said: "The more coffee you drank, the more effect
we saw."
The caffeine in coffee doesn't seem to be the link, since the same reduction
was seen for consumption of decaffeinated coffee, she said. Instead, "it has
something to do with insulin and glucose metabolism," Wilson said. "A number of
studies have found that coffee is associated with a reduced risk of diabetes."
This study is just a starting point for establishing a relationship between
coffee and prostate cancer, Wilson stressed. "At this point, we would just like
to confirm whether it exists in different populations," she said. "We hope that
this study drives more research so that we really know what is going on."
The other study, by Stacey A. Kenfield, a research associate at the Harvard
School of Public Health, looked at the levels of physical activity among 2,686
men in the study who were diagnosed with prostate cancer. It found, as many
other studies have, that exercise is good for overall health, with a 35 percent
lower death rate for men who reported three or more hours a week of vigorous
physical activity, such as jogging, biking, swimming or playing tennis.
And the death rate from prostate cancer for men who exercised vigorously was 12
percent lower than for those who didn't -- a figure that did not quite reach
the level of statistical significance because the numbers were small, Kenfield
explained.
Nevertheless, "this is the first study to show an effect of physical activity
not only on overall survival, but on prostate cancer survival," she said.
It's already well known how physical activity reduces overall mortality,
Kenfield said. "It affects immune function and reduces inflammation, among the
major processes involved. But it's not clear yet how it is related to prostate
cancer and survival."
More information
Details on prostate cancer are provided by the U.S. National Cancer Institute.