Weight gain after menopause ups breast cancer risk

NEW YORK (Reuters Health) – Women who gain weight after
menopause increase their risk of developing invasive breast
cancer. Conversely, weight loss reduces the risk, researchers
report.

The findings come from an analysis of data from the Nurses
Health Study, published in the July 12 issue of the Journal of
the American Medical Association.

Dr. A. Heather Eliassen, from Brigham and Women’s Hospital
in Boston, and her team point out that many studies have
established the relationship between weight gain and increased
breast cancer risk. However, the few studies that evaluated the
effect of weight change after menopause have yielded
conflicting results.

They therefore studied these relationships in a group of
49,514 women between 30 and 55 years old who were premenopausal
in 1976, had no history of cancer, and became postmenopausal or
underwent removal of both ovaries over the course of the study.

At follow-up in 2002, there were 2376 cases of invasive
breast cancer among postmenopausal subjects whose weight had
been documented.

Dr. Eliassen and her team accounted for other risk factors
for breast cancer and found that the risk of developing breast
cancer for women who gained 25 kilograms or more since age 18
was 45 percent higher than for those whose weight remained
stable. The risk was increased by 18 percent for women who
gained 10 kg or more after menopause.

Among women who lost at least 10 kg before menopause, the
risk dropped 16 percent, while women who lost at least 10 kg
after menopause decreased their risk by 23 percent. For those
who maintained their weight loss after menopause, the risk
dropped by 57 percent.

However, few women lose weight after menopause, the
researchers point out. Therefore, “women should avoid weight
gain throughout adult life rather than count on losing weight
after menopause,” Eliassen’s group advises, to cut the risk of
breast cancer.

SOURCE: Journal of the American Medical Association, July
12, 2006.