Exercise reduces risk for endometrial cancer

Women who exercise regularly are about 30% less likely to develop endometrial cancer than those who are sedentary, according to a meta-analysis of 5 large, prospective cohort studies published through December 2009.

Researchers at the National Cancer Institute also found that women who engage in vigorous exercise for at least 20 minutes at least 3 times per week but who sit on average for 9 or more hours per day have twice the risk for developing endometrial cancer as women who sit fewer than 3 hours per day. Their data suggest that that sitting time contributes to endometrial cancer risk, independent from a woman's participation in moderate-to-vigorous–intensity physical activity.

The authors of the study hypothesize that the association between sedentary behavior and endometrial cancer occurrence is at least a partial function of the effect of prolonged sitting on body weight. Further, they estimate that if women exercised vigorously 5 or more times per week and sat for 4 hours or fewer per day, then about one-third of endometrial cancers could be avoided.