The links between weight gain, menopausal hormone therapy, and breast Ca

Women whose body mass index increases as they get older and who don't use menopausal hormone therapy may have an increased risk of developing breast cancer, according to a report in the Oct. 22 Archives of Internal Medicine.

Jiyoung Ahn, PhD, of the National Cancer Institute in Bethesda, Md., and colleagues followed 99,039 postmenopausal women, aged 57 years and older, who were participants in the National Institutes of Health-AARP Diet and Health Study. Weight, height, and waist and hip circumferences at ages 18, 35, 50 years, and as of 1996, were determined by questionnaire. Breast cancer incidence through 2000 was determined by follow-up mailings and public database searches.

Among women who had never used menopausal hormone therapy or who had stopped using it, weight gains at ages 18-35 years, 35-50 years, and 50 years and older were each consistently associated with an increased risk of breast cancer. Women who had been obese throughout their lives had no increased risk of breast cancer relative to women who had consistently maintained a normal weight. No relationship was observed between those who maintained or lost weight as adults and breast cancer.

Ahn J, Schatzkin A, Lacey Jr JV. Adiposity, Adult Weight Change, and Postmenopausal Breast Cancer Risk. Arch Intern Med. 2007;167: 2091-2102.