Study Finds Link Between Exercise and Cancer Incidence in Black Women.

Regular exercise, including brisk walking, is associated with a decrease in the incidence of breast cancer in African American women, according to a new study led by BU School of Public Health researchers.

In the study, published in the journal Cancer Epidemiology, Biomarkers & Prevention, the researchers from BU’s Slone Epidemiology Center found strong evidence linking physical exercise to a lower rate of breast cancer in African American women — a group in which previous evidence has been lacking.

The researchers relied on a large prospective study of the health of black women, the Black Women’s Health Study (BWHS), which collected information about exercise habits, such as time spent exercising per week and type of exercise. The study followed more than 44,000 African American women over a span of 16 years and observed whether they developed breast cancer.

The research team found that women who exercised vigorously for seven or more hours each week were 25 percent less likely to develop breast cancer, compared to those who exercised less than one hour each week. Examples of vigorous activity include basketball, swimming, running and aerobics. The results were similar if women walked briskly; there was no benefit for walking at normal pace. The results did not differ by the estrogen receptor status of the breast cancer.

Lynn Rosenberg, professor of epidemiology at BUSPH and principal investigator of the Black Women’s Health Study, said that while expert review panels have accepted a link between physical exercise and breast cancer incidence, “most study participants have been white women. This is the first large scale study to support that vigorous exercise may decrease incidence of breast cancer in African American women.”

Funding for the study was provided by the National Cancer Institute.