Framingham Heart Study: A long-term, ongoing cardiovascular cohort study that began in 1948 in Framingham, Massachusetts, and has provided valuable insights into heart disease risk factors. Nurses' Health Study: Started in 1976, this study follows registered nurses to investigate the long-term effects of various risk factors on women's health. British Doctors Study: Launched in 1951, this study provided critical evidence on the health risks associated with smoking.
