NEW YORK (Reuters Health) – Physical activity, even at light or moderate intensities, attenuates the risk of endometrial cancer associated with excess weight, according to findings from the American Cancer Society’s prospective Cancer Prevention Study II Nutrition Cohort study.

Dr. Alpa V. Patel and colleagues at the American Cancer Society in Atlanta identified 466 incident cases of endometrial cancers between 1992 and 2003 among approximately 43,000 postmenopausal women with intact uteri.

Questionnaire responses showed that physically active women engaged primarily in low- to moderate-intensity activities, such as walking, biking, aerobics or dancing, equivalent to about 2 hours of moderately paced walking per week.

“All measures of physical activity and the avoidance of sedentary behavior were associated with lower endometrial cancer risk,” Dr. Patel and her group report in the October 15th issue of the International Journal of Cancer.

However, physical activity was strongly associated with reduced risk only among women who were overweight or obese (p = 0.003).

“Since physical activity, even in the absence of weight loss, significantly improves insulin sensitivity and has direct effects on bioavailable estrogen,” the authors propose that “it is biologically plausible that overweight or obese women engaging in regular physical activity may experience a greater risk reduction compared to active, normal weight women.”

Dr. Patel’s team calls for more research into the link between light-intensity activity and endometrial cancer risk reduction in order to “strengthen public health recommendations in this regard.”

Reference:
Int J Cancer 2008;123:1877-1882.