11 Aug Breast Cancer Incidence Lower Among Physically Active Women
Medical Research: What are the main findings of the study?
Response: With prospective data from the Black Women’s Health Study, we assessed vigorous exercise and walking in relation to incidence of invasive breast cancer . We found that the overall incidence of breast cancer was lower among women who exercised vigorously or walked briskly than among women who were sedentary. The reduction was most apparent among women who exercised at least 5 hours per week. The association of exercise with breast cancer risk did not differ by estrogen receptor status of the breast tumor, but further study is needed to firmly establish this. Sitting for long periods at work or watching television was not significantly associated with breast cancer incidence.
Medical Research: Were any of the findings unexpected?
Response: The findings are the first from a follow-up study of physical activity and breast cancer in African American women. There has been much more research on white women, with studies suggesting that exercise is associated with decreased incidence of breast cancer. Since African American and white women differ in many characteristics, it could not be assumed that the findings would be the same regardless of racial background.
Medical Research: What should clinicians and patients take away from your report?
Response: There are few actions that women can take to reduce their risk of breast cancer. The present findings are very encouraging because they indicate that if women exercise, they may reduce their risk of developing breast cancer. Clinicians should encourage patients to exercise for this reason (and because exercise reduces risk of many other adverse health outcomes such as diabetes, heart disease, and depression), and women should take these results as further motivation to include regular exercise in their daily lives.
Medical Research: What recommendations do you have for future research as a result of this study?
Response: Black women are more commonly affected by estrogen receptor negative breast cancer than white women, and these cancers have a worse prognosis than other types of breast cancer. Further research is needed to establish clearly whether exercise reduces the incidence of estrogen receptor negative breast cancer, and if so, to elucidate the mechanism.