December 3, 2009 (Oakland, Calif.) – Breastfeeding a child may lower a woman’s risk of developing Metabolic Syndrome, a condition linked to heart disease and diabetes in women, according to a Kaiser Permanente study that appears online in Diabetes: The Journal of the American Diabetes Association. The protective association was even stronger for women who had gestational diabetes during pregnancy, according to the study’s lead author, Erica Gunderson, PhD, an epidemiologist and research scientist at Kaiser Permanente’s Division of Research in Oakland, Calif.
Breastfeeding a child lowers risk by 39 to 56 percent (depending on the
duration of breastfeeding) for women without gestational diabetes, and
44 to 86 percent (depending on the duration of breastfeeding) for women
with gestational diabetes, researchers said. Investigators looked at
durations that included 0-1 month of lactation up to greater than 9
months of lactation.
Previous research has shown that lactating women have more favorable
blood levels of glucose and lipids within several weeks after delivery
than women who were not lactating. Other studies have reported much
weaker protective associations of breastfeeding with the presence of
Metabolic Syndrome and diabetes in middle-aged and older women.
Funded by the U.S. National Institutes of Health, this 20-year
prospective study is the first to measure all components of Metabolic
Syndrome both before pregnancy and after weaning in women of
childbearing age, enabling researchers to examine breastfeeding in
relation to new onset of Metabolic Syndrome, explained Gunderson.
“The findings indicate that breastfeeding a child may have lasting
favorable effects on a woman’s risk factors for later developing
diabetes or heart disease,” she said, explaining that the benefits don’t
appear to be due to differences in weight gain, physical activity, or
other health behaviors. However, in this study, less belly fat and
higher levels of good cholesterol (HDL-C) were characteristic of women
who did not develop Metabolic Syndrome, Gunderson said.
Among the 704 women who were aged 18 to 30 years at enrollment, had
never previously given birth and were free of Metabolic Syndrome before
all their pregnancies, there were 120 new cases of Metabolic Syndrome
after pregnancies during 20 years of follow-up.
“The Metabolic Syndrome is a clustering of risk factors related to
obesity and metabolism that strongly predicts future diabetes and
possibly, coronary heart disease during midlife and early death for
women,” Gunderson said.
“Because the Metabolic Syndrome affects about 18 to 37 percent of U.S.
women between ages 20-59, the childbearing years may be a vulnerable
period for its development. Postpartum screening of risk factors for
diabetes and heart disease may offer an important opportunity for
primary prevention.”
Recent studies suggest a stronger link between Metabolic Syndrome to
diabetes than coronary heart disease.
Another recent Kaiser Permanente study by Gunderson published in the
American Journal of Obstetrics and Gynecology in August 2009 found that
women with gestational diabetes are 2.5 times more likely to develop
Metabolic Syndrome after pregnancy.
Gunderson explained that further research is needed to learn more about
the mechanism(s) through which lactation may influence risk of
cardiovascular disease or diabetes. Further research also is needed to
learn about whether lifestyle modifications, including lactation
duration, may affect development of coronary artery disease and type 2
diabetes, particularly among high-risk groups, such as women with a
history of gestational diabetes.
This study was part of the Coronary Artery Risk Development in Young
Adults (CARDIA) Study, a multi-center, longitudinal, population-based,
observational study designed to describe the development of risk factors
for coronary heart disease in young black and white adults recruited
from four geographic areas in the United States: Birmingham, Ala..;
Chicago; Minneapolis; and Oakland.
Additional investigators on the study include: David R. Jacobs, Jr.,
University of Minnesota Division of Epidemiology and Community Health
and University of Oslo, Department of Nutrition; Vicky Chang, Kaiser
Permanente Division of Research; Cora E. Lewis, University of Alabama
Birmingham, Division of Preventive Medicine and the Diabetes Research
and Training Center; Juanran Feng, Kaiser Permanente Division of
Research; Charles P. Quesenberry, Jr., Kaiser Permanente Division of
Research; and Stephen Sidney, Kaiser Permanente Division of Research.
The study was funded by U.S. National Institutes of Health (Contracts #
N01-HC-48047, N01-HC-48048, N01-HC-48049, N01-HC-48050, and
N01-HC-95095, from the National Heart, Lung, and Blood Institute, and
Career Development Award, Grant number K01 DK059944 from the National
Institute of Diabetes, Digestive and Kidney Diseases) and a Research
Award from the American Diabetes Association.
About the Kaiser Permanente Division of Research (www.dor.kaiser.org)
The Kaiser Permanente Division of Research conducts, publishes, and
disseminates epidemiologic and health services research to improve the
health and medical care of Kaiser Permanente members and the society at
large. It seeks to understand the determinants of illness and well-being
and to improve the quality and cost-effectiveness of health care.
Currently, DOR’s 400-plus staff is working on more than 250
epidemiological and health services research projects.
About Kaiser Permanente
Kaiser Permanente is committed to helping shape the future of health
care. We are recognized as one of America's leading health care
providers and not-for-profit health plans. Founded in 1945, our mission
is to provide high-quality, affordable health care services to improve
the health of our members and the communities we serve. We currently
serve 8.6 million members in nine states and the District of Columbia.
Care for members and patients is focused on their total health and
guided by their personal physicians, specialists and team of caregivers.
Our expert and caring medical teams are empowered and supported by
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innovations, clinical research, health education and the support of
community health. For more information, go to: www.kp.org/newscenter .