Increased physical activity is associated with decreased breast cancer risk in both black women and white women, according to a new study published in the Journal of the National Cancer Institute.

Dozens of studies have examined the association between recreational physical activity and breast cancer. However, questions remain about whether a reduction in risk is observed in all population subgroups. To examine the association between physical and activity and breast cancer in black and white women, Leslie Bernstein, Ph.D., of the University of Southern California Norris Comprehensive Cancer Center in Los Angeles, and colleagues examined data from a case-control study of more than 8,000 black women and white women ages 35 to 64.

They found that, among all women, increased levels of lifetime exercise activity were associated with decreased breast cancer risk. This inverse association did not differ between black and white women. They also noted that no modification of risk was observed by disease stage, estrogen receptor status, or any breast cancer risk factor other than history of breast cancer in a first-degree family member. In women who had a first-degree family member with breast cancer, physical activity was not associated with decreased risk of breast cancer.

SOURCE:
Journal of the National Cancer Institute, November 16, 2005