Study Shows Vigorous Exercise Reduces Risk of Breast Cancer in African-American Women
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Reviewed By Laura J. Martin, MD
Oct. 4, 2010 -- Postmenopausal African-American women who exercise vigorously for more than two hours a week can reduce their risk of developing breast cancer by 64% compared to women of the same race who are sedentary, according to new research.
Scientists identified 97 African-American breast cancer patients living in the Washington, D.C., area, matching them with 102 women of the same race who had not been diagnosed with the disease.
Participants filled out questionnaires about their exercise routines.
Researchers say postmenopausal women who exercised vigorously more than two hours a week in the past year had a 64% reduced risk of breast cancer, compared to women who didn't exercise at all.
What is more, women who said they engaged in moderate exercise, such as walking, had a 17% reduced risk, compared to same-race women who were sedentary.
"I was surprised that we did not find a significant effect in pre-menopausal women, but it may be because we need a larger sample," study researcher Vanessa Sheppard, PhD, an assistant professor of oncology at the Lombardi Comprehensive Cancer Center, says in a news release.
"We also know from other studies that being physically active can have benefits in other diseases that occur at high rates in African-American women, such as diabetes and hypertension," Sheppard says. "Four out of five African-American women are either overweight or obese, and disease control is a particularly important issue for them."
The issue is important, Sheppard says, because while more white women are diagnosed with breast cancer, there are important differences in breast cancer between white and African-American women.
African-American women, for example, are at higher risk of developing pre-menopausal breast than do white women, and comparatively, more African-American women develop the most aggressive form of the disease, which is known as triple-negative breast cancer.
The researchers say that when they examined the effect of total physical activity, combining vigorous activity at least 2 hours per week with walking, they saw significant gains for both pre- and postmenopausal women.
"We suggest that our findings, while promising, should be interpreted with caution," Sheppard says. "This is a pilot study and a larger, more rigorous study is needed to precisely quantify the effect of exercise on development of breast cancer."
She says, however, that it's "fair to conclude that if African-American women exercise, they can help take charge of their health."
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.
SOURCES: News release, American Association for Cancer Research.Third AACR Conference on the Science of Cancer Health Disparities, Miami, Sept. 30-Oct. 3, 2010.
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