To address cardiovascular disease, cancer, and osteoporosis, the most common causes of death, disability, and impaired quality of life in postmenopausal women. The three major components of the WHI are: a randomized controlled clinical trial of hormone replacement therapy (HRT), dietary modification (DM), and calcium/vitamin D supplementation (CaD); an observational study (OS); and a community prevention study (CPS). On October 1, 1997, administration of the WHI was transferred to the NHLBI where it is conducted as a consortium effort led by the NHLBI in cooperation with the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the National Cancer Institute (NCI), and the National Institute on Aging (NIA).