A study conducted by the British group Cancer Research UK found Ã¢â‚¬Å“convincing evidenceÃ¢â‚¬Â that increased physical activity, especially housework, may help lower a womanÃ¢â‚¬â„¢s risk of getting breast cancer. The report appeared in Cancer Epidemiology Biomarkers & Prevention, the journal of the American Association for Cancer Research.
Researchers studied more than 218,000 premenopausal and postmenopausal women, ages 20 to 80, from nine European countries, and divided the types of activity into three groups: recreational, household, and occupational. Household activity was found to have the most significant effect on breast cancer risk. Housework, home repair, gardening, and stair climbing were combined to obtain an overall estimate of household activity.
According to the review, Ã¢â‚¬Å“The decrease in breast cancer risk for the most physically active women compared with the least active women is, on average, 20 to 40 percent, with some studies observing up to 70 percent risk reductions. It is hypothesized that physical activity affects breast cancer through changes in menstrual characteristics, body size, metabolism of endogenous hormones, including sex hormones, insulin, and insulin-like growth factors, or immune function.Ã¢â‚¬Â
Perhaps the most surprising finding was that household activity had an even greater effect on breast cancer risk than more strenuous exercise. Ã¢â‚¬Å“Increased nonoccupational physical activity and, in particular, increased household activity were significantly associated with reduced breast cancer risk, independent of other potential risk factors,Ã¢â‚¬Â the authors write. Ã¢â‚¬Å“These results strengthen the consistency of findings about the protective role of physical activity on breast cancer riskÃ¢â‚¬Â¦. Moderate forms of physical activity, such as household activity, may be more important than less frequent but more intense recreational physical activity in reducing breast cancer risk in European women.Ã¢â‚¬Â