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2001/06/01 -Women who use estrogen after menopause have lower death rates from all causes
than those who do not, reports American Cancer Society researchers, and this
reduction in death is greatest for coronary heart disease and for thinner
women.
These findings, based on an analysis of data from the Society’s landmark
Cancer Prevention Study II, is published in the January 15th edition
of the American Journal of Epidemiology.
Carmen Rodriguez, Ph.D. and colleagues from the American Cancer Society’s
Epidemiology and Surveillance Research Department, responding to recent evidence
suggesting that the impact of estrogen use on disease outcomes may vary by body
mass, studied a group of 290,827 postmenopausal, primarily elderly U.S. women.
These women had no history of cancer or cardiovascular disease when they were
enrolled in the 1.2 million participant American Cancer Society prospective
study in l982.
After 12 years of follow-up, death rates from all causes among these women
were nearly 20% lower (Rate Ratio = 0.82) among estrogen users compared with
non-users.
Estrogen users typically have healthier lifestyles and better cardiovascular
profiles than do non-users, which according to the researchers may explain in
part their lower death rates. However, the findings in this analysis, say the
authors, show a coronary heart disease rate that is larger than would be
explained by this "healthy user" bias.
The largest decrease in death rates was found in coronary heart disease (CHD)
and other circulatory diseases, (RR = 0.66 CHD, RR = 0.70, other circulatory
diseases). The rate ratio for CHD mortality associated with estrogen use was
significantly lower for the leanest women, those with a body mass index (BMI) of
less than 22. These women had a RR of 0.49. Body mass index is a ratio of weight
in pounds divided by height in inches squared. A woman with BMI of less than 25
is considered thin or normal weight, between 25 and 30 is considered overweight,
and BMI of 30 or more is considered obese.
"Estrogen did not seem to lower the risk of dying from coronary heart disease
for women with a BMI of 30 or higher," reports Dr. Rodriguez. "Overall, the risk
of dying from coronary heart disease increases with greater body mass index.
Estrogen use decreases risk of dying from coronary heart disease among thin and
overweight women, but no impact was observed among obese women" she
observes.
The association of cancer mortality with estrogen use was found to be minimal
reports the study team. Cancer death rates were modestly lower among estrogen
users (RR = 0.91) and did not change overall in relation to BMI.
Some previous studies of women with established CHD have reported that the
use of estrogen did not protect against subsequent coronary disease events.
"Our findings do not conflict with findings from those studies," says Dr.
Rodriguez. "That’s because we were looking at the hormone’s effect on women with
no pre-existing heart disease."
"Our study does suggest that when a woman and her physician are in the
process of deciding for or against using hormone replacement at menopause, body
size should be another consideration in the estimation of potential risks and
benefits of the therapy," she added.
The American Cancer Society is the nationwide community-based
voluntary health organization dedicated to eliminating cancer as a major health
problem by preventing cancer, saving lives and diminishing suffering from
cancer, through research, education, advocacy and service.
For information about cancer, call toll-free anytime 1-800-ACS-2345 or visit
the American Cancer Society website at www.cancer.org.
Joann Schellenbach
National Director Media Relations
American Cancer Society
212-382-2169
jschelle@cancer.org
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