The Nurses' Health Study, established in 1976, and the Nurses' Health Study II, established in 1989, are among the largest investigations into the risk factors for major chronic diseases in women. These studies have grown to include a team of clinicians, epidemiologists, and statisticians at the Channing Laboratory, along with collaborating investigators and consultants in the surrounding medical community of the Harvard Medical School, Harvard School of Public Health, Brigham and Women's Hospital, Dana Farber Cancer Institute, Boston Children's Hospital, and Beth Israel Deaconess Medical Center.