120 000 Nurses Who Shook Public Health.

Everyone in public health has heard of the first Nurses’ Health Study (NHS). This cohort of 121 700 nurses assembled in 1976 has generated a substantial part of what we know today about women’s health and the prevention of chronic diseases. A brilliant and competent team of investigators from Harvard University originated it 40 years ago and have conducted it since then, but as every epidemiologist knows, wonderful ideas do not necessarily translate into great studies. The NHS is the encounter of a wonderful idea (i.e., enrolling nurses in a large cohort study) and the historically outstanding response from nurses, who made the study theirs. Nurses joined, persisted, and used their unique and essential skills to make this cohort study an exemplar.