Weight Gain May Increase Breast Cancer Risk
Women Who Gain Weight as Adults May Face Higher Breast Cancer Risks
Feb. 26, 2004 -- Women who put on more than 70 pounds as adults
may be twice as likely to develop breast cancer during menopause as women who
maintain their weight.
A new study suggests that for women not taking hormone
replacement therapy (HRT), weight gain after age 18 may be a strong predictor
of menopausal breast cancer risk.
Researchers found that postmenopausal women not taking HRT who
gained more than 20 pounds since age 18 were much more likely to develop breast
cancer than women who stayed within five pounds of their teenage weight.
"These findings further illustrate the importance of
maintaining a healthy body weight throughout life," says researcher Heather
Spencer Feigelson, PhD, MPH, senior epidemiologist at the American Cancer
Society, in a news release. "Even modest weight gain since age 18 was
associated with increased risk of postmenopausal breast cancer.
"Avoiding weight gain is one of the few ways we know of to
reduce the risk of breast cancer among postmenopausal women," says
The findings appear in the February issue of Cancer
Epidemiology, Biomarkers & Prevention.
Extra Pounds Increase Breast Cancer Risks
The study involved more than 62,000 postmenopausal women who
took part in the American Cancer Society's Cancer Prevention Study II.
The women, who were between the ages of 50 and 74 at the start
of the study in 1992, were asked about their current weight and their weight at
age 18. Total weight change from age 18 to their age in 1992 was calculated.
During the follow-up period, 1,934 breast cancer cases occurred among the
Researchers found that among non-HRT users, women who gained 21
to 30 pounds since age 18 were 40% more likely to get breast cancer than women
who had gained no more than five pounds. And the risks increased as the women's
Women who gained more than 70 pounds were twice as likely to
develop breast cancer as the women who maintained their weight.
Although adult weight gain was strongly related to breast
cancer risk among non-HRT users, adult weight gain was unrelated to breast
cancer risk among women on HRT. Breast cancer risks among these HRT users were
nonetheless higher, regardless of adult weight gain.
Researchers say the findings support the idea that body fat
increases menopausal breast cancer risk by increasing estrogen levels in the
body. Women on HRT already have higher levels of estrogen as a result of the
hormones they're taking, which may mask any additional effect of body fat.