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How Much Women Exercise Better Gage of Heart Risk
than Body Weight
Sept. 8, 2004 – A woman’s physical activity level
is a better measure of heart disease than is excess weight, according a
a study conducted at four academic medical centers and sponsored by the
National Heart, Lung, and Blood Institute (NHLBI).
Although excess weight is a recognized risk factor
for the development of cardiovascular disorders, a woman’s level of
physical activity appears to be a more useful predictor of existing
coronary artery disease and future cardiovascular events such as
congestive heart failure, unstable angina and heart attack, according to
the study.
“Using such measures as body mass index, waist
circumference, waist-hip ratio and waist-height ratio, many studies have
shown that being overweight increases cardiovascular risk. Few studies,
however, have examined the specific role of physical activity and
fitness,” said senior author C. Noel Bairey Merz, MD, cardiologist,
director of Cedars-Sinai Medical Center’s Preventive and Rehabilitative
Cardiac Center, and director of the Women’s Health Program. “The
tendency to focus only on weight as a risk factor fails to address the
related but more important lack of physical fitness among overweight
individuals.”
Data for the study were derived from findings among
906 women in the ongoing Women’s Ischemia Syndrome Evaluation (WISE)
study, which Dr. Bairey Merz directs as principal investigator. From
1996 to 2000, 936 women with chest pain, suspected narrowing of the
coronary arteries, or both were enrolled in the WISE study. They
underwent evaluations, coronary angiography and any other necessary
diagnostic procedures, and agreed to long-term follow-up.
Body mass index and other “anthropometric” measures
were taken, and patient data were categorized by normal weight,
overweight and obesity. To assess physical activity and ability, study
participants were asked to complete two standardized self-assessments –
the Duke Activity Status Index (DASI) questionnaire and the
Postmenopausal Estrogen-Progestin Intervention Questionnaire (PEPI-Q).
Among the 906 participants, 76 percent were
categorized as overweight and 41 percent obese. But despite the fact
that women in the higher BMI categories had numerous risk factors for
coronary artery disease, there was no difference in the presence or
severity of disease, based on angiograms.
Seventy percent of all participants had low
physical activity levels, reflected in low DASI and PEPI-Q scores, and
the researchers found significant associations between these values and
the existence of obstructive coronary artery disease. Also, while
excessive body weight did not correlate directly with increased risk of
later adverse events, low activity scores did. In fact, they were found
to be significant independent predictors of both adverse events and
major adverse events. When analyzed by categories of weight and
activity, women who were at least moderately active had significantly
greater event-free survival than women with low activity scores, no
matter which weight category they were in.
“Because physical fitness has beneficial effects on
many factors related to cardiovascular risk – including obesity –
increased activity appears to be an ideal therapy for women with
coronary heart disease. The American Heart Association’s prevention
guidelines recommend that women accumulate at least 30 minutes of
moderate-intensity physical activity on most or all days of the week.
Physical fitness assessment and intervention should be included in the
management of all women at risk for heart disease,” said Dr. Bairey
Merz, who holds Cedars-Sinai’s Women’s Guild Chair in Women’s Health and
serves as national spokesperson for the Women’s HeartAdvantage campaign.
This nationwide program is designed to help women learn more about the
symptoms and treatment of heart disease and heart attacks.
“Despite the fact that excess body weight is
associated with numerous risk factors including hypertension, diabetes
and metabolic syndrome, we found the body mass index to be a poor
predictor of both baseline angiographic coronary artery disease as well
as prospective risk of adverse events,” Dr. Bairey Merz said. “Our
findings suggest that self-reported level of physical activity and
functional capacity are more important than weight status or body type
for determining cardiovascular risk in women.”
Study results appear in the September 8 issue of
the Journal of the American Medical Association (JAMA).
The study was also supported by grants from the
Gustavus and Louis Pfeiffer Research Foundation, the Women’s Guild of
Cedars-Sinai Medical Center, the Ladies Hospital Aid Society of Western
Pennsylvania, and QMED Inc.
A Magnet Nursing accredited facility, Cedars-Sinai
Medical Center is one of the largest nonprofit academic medical centers
in the Western United States. For the fifth straight two-year period, it
has been named Southern California’s gold standard in health care in an
independent survey. Cedars-Sinai is internationally renowned for its
diagnostic and treatment capabilities and its broad spectrum of programs
and services, as well as breakthroughs in biomedical research and
superlative medical education. It ranks among the top 10 non-university
hospitals in the nation for its research activities and was recently
fully accredited by the Association for the Accreditation of Human
Research Protection Programs, Inc. (AAHRPP).
Citation: Journal of the American Medical
Association, September 8: “Relationships of Physical Activity vs Body
Mass Index With Coronary Artery Disease and Cardiovascular Events in
Women.”
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