<P> The Nurses ' Health Study ( NHS ) , is a series of prospective studies that examine epidemiology and the long - term effects of nutrition , hormones , environment , and nurses ' work - life on health and disease development . The studies are among the largest investigations into risk factors for major chronic diseases ever conducted . The NHS studies have led to many insights on health and well - being , including cancer prevention , cardiovascular disease , and diabetes ( type 2 ) . The studies include clinicians , epidemiologists , and statisticians at the Channing Laboratory , Harvard Medical School , Harvard School of Public Health , and several Harvard - affiliated hospitals , including Brigham and Women 's Hospital , Dana -- Farber Cancer Institute , Children 's Hospital Boston , and Beth Israel Deaconess Medical Center . </P>
the nurses ' health study is an example of what type of study
long - term