According to a new study published in the British Journal of Cancer, higher levels of physical activity were associated with a decreased risk for breast cancer in both pre- and postmenopausal women.
A large prospective study included 47,456 premenopausal and 126,704 postmenopausal women from the UK Biobank. Self-reported physical activity data and accelerometer-derived data were determined for 6443 and 20,785 women, respectively.
After adjustment for adiposity, women in the top vs bottom quartile of self-reported physical activity had a lower risk for premenopausal (relative risk [RR], 0.75; 95% CI, 0.60-0.93) and postmenopausal breast cancer (RR, 0.87; 95% CI, 0.78-0.98). A 21 per cent (RR, 0.79; 95% CI, 0.66-0.95) decrease in premenopausal risk and a 16 per cent (RR, 0.84; 95% CI, 0.73-0.96) decrease in postmenopausal risk were observed for breast cancer for every 5 milli-gravity increase in accelerometer-based physical activity score adjusted for adiposity.
The authors concluded: "These findings suggest a protective effect of physical activity on breast cancer risk for all women, beyond the role of adiposity." They call for further research to investigate the mechanisms underlying the association between physical activity and risk for breast cancer.