Niehoff NM, et al. - Considering the consistent association of recreational physical activity with reduced breast cancer risk, researchers examined the association of physical activity with breast cancer risk in a large population with a family history of breast cancer. Study participants included 50,884 women who had a sister with breast cancer but no prior breast cancer themselves at enrollment, and reported all recreational sport/exercise activities they participated in over the past 12 months. Physical activity was noted to be associated with reduced postmenopausal, but not premenopausal, breast cancer risk. No variation in the associations was noted with the extent of family history.