Body Mass Index Gain Throughout Adulthood May Increase Risk Of Postmenopausal Breast Cancer

Reported mid-life increase in body mass index (BMI) may lead to substantially higher risk of postmenopausal breast cancer, according to results of a prospective cohort study presented at the American Association for Cancer Research 101st Annual Meeting 2010.

In previous studies, excess weight has been linked with increased risk of postmenopausal breast cancer. Scientists have speculated that in postmenopausal women, estrogen produced in adipose tissue, or body fat, may promote breast cell proliferation. Relatively few studies have looked specifically at increase in BMI and its timing in relation to postmenopausal breast cancer risk, which this study investigated.

The researchers analyzed information from 72,007 women in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial cohort, who were 55 to 74 years old at study entry. The analysis included 3,677 cases of postmenopausal breast cancer, which makes this one of the larger studies of its kind, according to the researchers.

The researchers observed the strongest associations among women who had never used menopausal hormone therapy; results were shown only for this group of women. Read more