Dropping weight might do more than make an older woman feel good. New research suggests it could lower her odds of breast cancer.
The study included over 61 000 postmenopausal women with no prior breast cancer and normal mammogram results. Their weight was checked at the start of the study and again three years later.
During an average follow-up of just over 11 years, about 3 000 new cases of invasive breast cancer were diagnosed in the group.
Women who lost 5% or more of their body weight had a 12% lower breast cancer risk than those whose weight remained the same, the findings showed.
In addition, weight gain of 5% or more was not associated with risk of breast cancer overall, but was associated with a 54% higher risk of triple negative breast cancer. However, the association doesn't prove cause and effect.
The study was published online October 8 in the journal Cancer.
"Our study indicates that moderate, relatively short-term weight reduction was associated with a statistically significant reduction in breast cancer risk for postmenopausal women," said Dr. Rowan Chlebowski, from the City of Hope National Medical Center, in Duarte, California.
"These are observational results, but they are also supported by randomized clinical trial evidence," he said. And prior studies showed that "adopting a low-fat dietary pattern that was associated with a similar magnitude of weight loss resulted in a significant improvement in breast cancer overall survival," Chlebowski added in a journal news release.
Taken together, the studies "provide strong correlative evidence that a modest weight-loss programme can impact breast cancer," Chlebowski concluded.