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Gynäkologie
Klimakterium
& Menopause |
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Moderate Physical Activity Is Critical For Reducing The Risk Of Chronic Disease In Older Women |
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Getting
regular, moderate-intensity exercise may be critically important
for postmenopausal women who want to reduce their risk of
cancer, heart disease and other chronic diseases, according
to a study led by researchers at Fred Hutchinson Cancer Research
Center in Seattle. The reason: exercise effectively reduces
intra-abdominal fat, a hidden risk factor for many chronic
illnesses.
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Lead
investigator Anne McTiernan, M.D., Ph.D., a member of Fred
Hutchinson's Public Health Sciences Division, and colleagues
report the results of the largest randomized clinical trial
to assess the effect of exercise on overall and intra-abdominal
obesity in postmenopausal women in the Jan. 15 issue of the
Journal of the American Medical Association. Researchers from
Fred Hutchinson, the University of Washington, Yale University
and the University of Colorado collaborated on the study.
"Even if a woman who exercises regularly doesn't see
the benefits of dramatic weight loss on her scale, our results
indicate that she can feel confident that she is improving
her health, because regardless of the amount of weight lost,
we now know that exercise reduces hidden intra-abdominal fat,
the most dangerous type of fat," said McTiernan, director
of Fred Hutchinson's Prevention Center and an international
expert on the impact of physical activity on cancer prevention.
"This study gives us direct evidence that exercise can
affect biology related to cancer and other chronic diseases
in older women."
Reducing intra-abdominal, or visceral, fat is important because
in addition to increasing the risk of cardiovascular disease
and diabetes, among other conditions, such fat can raise insulin
levels, which promotes the growth of cancer cells.
People with high levels of intra-abdominal fat may not even
know it, McTiernan said, because it is hidden, deposited around
the internal organs within the abdomen. "Most women don't
know about intra-abdominal fat, but they should, since it
is the most clinically significant type of fat and it's where
women tend to store fat after menopause."
Although it is known that so-called "apple-shaped"
people who store their fat around the stomach are at higher
risk for conditions such as diabetes, hypertension and stroke
than "pear-shaped" people who store their fat in
their buttocks and thighs, visceral obesity is not necessarily
correlated with body shape, McTiernan said. The only accurate
way to determine the presence and extent of intra-abdominal
fat is with imaging procedures such as CT or MRI scans.
"Because it is so costly to measure intra-abdominal obesity,
until now very little data has existed on the impact of exercise
on this dangerous, hidden health risk," she said.
This yearlong study involved more than 170 previously sedentary,
overweight, postmenopausal Seattle-area women. None took hormone-replacement
therapy. Half were randomly assigned to a moderate-intensity,
aerobic-exercise group and half, who served as a comparison
group, attended a weekly hour-long stretching class.
The members of the exercise group, who worked out at home
and at a gym for at least 45 minutes five days a week - an
amount similar to current national recommendations - achieved
significant reductions in weight, total body fat and intra-abdominal
fat. After a year on the program, while the amount of body
weight lost was modest yet statistically significant, the
exercisers lost between 3.4 percent and 6.9 percent intra-abdominal
fat while maintaining their calorie intake. Women who had
the highest adherence to the program experienced the largest
decreases in weight, total and intra-abdominal fat. The women
in the stretching group, in contrast, experienced a slight
gain in intra-abdominal fat.
"The beauty of exercise as a method to reduce total and
intra-abdominal fat - and therefore chronic disease - is that
it can be done by most women at low cost and with low risk
of side effects. In addition, exercise has many other health
benefits. The good news is that it is never too late to enjoy
the health benefits of exercise," McTiernan said.
Strengths of this study, compared to two previous trials that
looked at the impact of activity on intra-abdominal obesity,
include its large sample size (173 versus fewer than 25 subjects),
the length of the exercise intervention (one year compared
to less than six months), and its high adherence rates (81
percent of the exercisers completed 80 percent or more of
their prescribed 225 minutes per week of exercise).
Another strength of this study was its randomized, controlled,
clinical-trial design, considered the gold standard of study
designs in medicine. The participants met three times a week
with an exercise physiologist at an exercise facility, where
they performed treadmill walking and stationary biking. They
also exercised two days a week at home, doing exercises of
their own choosing, mostly walking.
"In this type of study, we can directly control for extraneous
factors and we directly observe what the women are doing rather
than just relying on what they report on questionnaires. Therefore,
we have more confidence in the results," she said.
The results of the study, funded by the National Cancer Institute,
are significant for older women who seek a natural way to
reduce their risk of chronic disease, said McTiernan, who
is also a research associate professor at the University of
Washington School of Medicine and School of Public Health
and Community Medicine.
"Most American women gain one to two pounds on average
every year, and that adds up to dangerous levels over a lifetime.
All women - especially those at risk for diabetes, cardiovascular
disease, cancer or high cholesterol - need to stop gaining
weight," she said. "Regular, moderate-intensity
exercise can help keep the weight from creeping on, which
can translate to improved health in the long run."
Source: Fred Hutchinson Cancer Research Center, Date:
2003-01-15
The
Fred Hutchinson Cancer Research Center, home of two Nobel
Prize laureates, is an independent, nonprofit research institution
dedicated to the development and advancement of biomedical
technology to eliminate cancer and other potentially fatal
diseases. Fred Hutchinson receives more funding from the National
Institutes of Health than any other independent U.S. research
center. Recognized internationally for its pioneering work
in bone-marrow transplantation, the center's four scientific
divisions collaborate to form a unique environment for conducting
basic and applied science. Fred Hutchinson is the only National
Cancer Institute-designated comprehensive cancer center in
the Pacific Northwest and is one of 41 nationwide.
For more information, visit the center's Web site at http://www.fhcrc.org.
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