Abstract
Two complementary studies in separate components of the Women's Health Initiative (WHI) examined relationships among weight loss, diet composition and breast cancer incidence and outcome in postmenopausal women. In the WHI Observational Study, 61,335 postmenopaus al women had their weight change determined over a 3-year period with subsequent follow-up. Women with weight loss greater than or equal to 5% had significantly lower breast cancer incidence compared to women with stable weight. In the WHI Dietary Modification randomized clinical trial involving 48,835 postmenopausal women, implementation of a low-fat eating pattern significantly reduced deaths after breast cancer. Thus, moderation regarding dietary composition and body weight maintenance can reduce a postmenopausal woman's risk of being diagnosed with breast cancer and of dying after breast cancer.