Postmenopausal women who lose weight may have reduced breast cancer risk

Postmenopausal Women Who Lose Weight May Have Reduced Breast Cancer Risk

Postmenopausal women who lose weight may significantly reduce their chances of developing breast cancer, according to National Institutes of Health-funded study presented at the 2017 San Antonio Breast Cancer Symposium.

Left – Wendy Barrington, UW assistant professor of nursing, Right – Kerryn Reding, UW assistant professor of nursing

“This study is important because it is one of the first to provide support for weight loss as a strategy to reduce breast cancer risk,” said Dr. Kerryn W. Reding, UW assistant professor of nursing and a study co-investigator.

“Previous studies have associated high body mass index with increased breast cancer risk, but did not look at whether reducing weight could also decrease risk,” she said. “This study goes a step further to show that women who are overweight or obese can reduce their breast cancer risk through weight loss.”

An estimated 65 percent of American women are overweight or obese.

The study analyzed data from the Women’s Health Initiative (WHI) Observational Study, which tracked the health of postmenopausal women between the ages of 50 and 79. Researchers are able to analyze the data gathered in that study to examine the relationship between lifestyle, health and risk factors and specific disease outcomes.

Study participants had a normal mammogram, no prior breast cancer and were not underweight with a Body Mass Index (BMI) less than 18.5.

Of the 61,335 patients enrolled in the study, 3,061 developed invasive breast cancer during an average of 11.4 years of follow-up. Compared to women with stable weight, those who lost weight were 12 percent less likely to develop breast cancer. Weight loss of 15 percent or more was associated with a 37 percent reduction in breast cancer incidence.

“With emerging evidence that weight loss can reduce the risk of breast cancer, nurses can encourage women to improve their nutritional and exercise habits as part of an evidence-based strategy for reducing breast cancer risk,” Reding said.

Dr. Wendy Barrington, UW assistant professor of nursing, was a study co-investigator.