Regular exercise, including brisk walking, is associated with a decrease in the incidence of breast cancer in African American women, according to a recent study.

Researchers from Boston University's Slone Epidemiology Center found strong evidence linking physical exercise to a lower rate of breast cancer in Black women, a group in which previous evidence has been lacking.

"Although expert review panels have accepted a link between physical exercise and breast cancer incidence, most study participants have been white women," Lynn Rosenburg, principal investigator of the study, said in a statement. "This is the first large scale study to support that vigorous exercise may decrease incidence of breast cancer in African American women."

For the study, researchers followed more than 44,000 African American women over a span of 16 years and observed whether they developed breast cancer. They collected information about exercise habits, such as time spent exercising per week and type of exercise.

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, but there was no benefit for walking at normal pace. The results did not differ by the estrogen receptor status of the breast cancer

The findings were recently published in Cancer Epidemiology, Biomarkers & Prevention.