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Obesity Boosts Risk for Aggressive Breast Cancer

Study Shows Link Between Obesity and Triple-Negative Breast Cancer

African-Americans, Younger Women Have Higher Risk

Triple-negative breast cancers are common among women who have a genetic predisposition known as BRCA1, and they also occur more often in African-American women and tend to occur in younger women.

While none of these risk factors is modifiable, Phipps says the new study suggests two potential interventions that may lower a woman’s risk for developing the disease.

“There are already hundreds of reasons for women to maintain a healthy weight and remain physically active,” she says. “This may be one more.”

University of Wisconsin associate professor Amy Trentham-Dietz, PhD, agrees.

“These findings suggest that avoiding obesity and staying active could lower a woman’s risk for all types of breast cancer, not just those that are estrogen-receptor positive,” she tells WebMD. “That is a very positive message.”

Number of Childbirths and Cancer Risk

Triple-negative breast cancers were first identified less than a decade ago, and Phipps says they are still something of a mystery to researchers and doctors.

Findings from a separate analysis of the WHI data, reported last week by Phipps and colleagues, also surprised the researchers. That study was published Feb. 24 online in the Journal of the National Cancer Institute.

The analysis suggested that the more children a woman has delivered, the higher her risk for the cancer. Women in the study who had never given birth had a 40% lower risk for triple-negative cancers than women who had.

Childbirth is known to be protective against estrogen-receptor positive breast cancers.

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