Timing of weight gain affects breast cancer risk
NEW YORK (Reuters Health) - New mothers now have even more incentive to shed pounds gained during pregnancy, other than wanting to fit into those pre-pregnancy jeans. A new study indicates an association between gaining weight in adulthood and an increased risk of breast cancer after menopause.
"We did find some suggestion that weight gain during the 30s and 40s, weight gain since a woman's first pregnancy and weight gain since menopause, especially for women with a longer time since menopause, may all be of importance in relation to postmenopausal breast cancer risk," the researchers report in the International Journal of Cancer this month.
It is well established that being overweight is a risk factor for breast cancer. Mounting evidence indicates that weight gain in adult life is more predictive of breast cancer risk than absolute body weight, but little is known about the impact of the timing of weight gain in adult life in relation to breast cancer risk.
Dr. Daikwon Han of Morehead State University in Kentucky and colleagues looked at this issue in 1,166 women with breast cancer and 2,105 without.
Han's team noted, among other things, a roughly 70 percent increased risk of breast cancer among postmenopausal women who gained more than 60 pounds between age 20 and menopause, compared with women who gained less than 20 pounds.
There was a 4 percent increase in breast cancer risk for each 11-pound increase in adult weight, the investigators report.
These results, Han and associates say, suggest that there are time periods of weight gain that have "greater impact" on breast cancer risk than others.
SOURCE: International Journal of Cancer, December 15, 2006.
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What breastcancer.org says about this article…
Timing of weight gain affects breast cancer risk
Overweight women have an increased risk, compared to average-weight women, of getting breast cancer after menopause. And being overweight can increase the risk of breast cancer coming back in women who have had the disease. This may be because fat cells make extra estrogen and other hormones, which might stimulate breast cell growth.
The study reviewed here adds to growing evidence that gaining weight as an adult can increase breast cancer risk. Gaining significant amounts of weight as an adult increased breast cancer risk more than maintaining the same weight through adulthood—regardless of starting weight.
This means that no matter what their starting weight was, women who gained more than 60 pounds between age 20 and the time they reached menopause were 70% more likely to be diagnosed with breast cancer than those who gained fewer than 20 pounds during that same time. Weight gain after menopause was also found to increase breast cancer risk.
These results do NOT mean it's OK to be overweight as you enter adulthood. Being overweight increases breast cancer risk, period. But the results do suggest that maintaining your weight as you get older is a very smart step toward keeping your breast cancer risk as low as it can be.
Visit the Breastcancer.org Lower Your Risk section to learn more about breast cancer risk and steps you can take to lower your risk, including maintaining a healthy weight and lifestyle.