Origins and early development of the case-control study: Part 2, The case-control study from Lane-Claypon to 1950.

The first modern case-control study was Janet Lane-Claypon's study of breast cancer in 1926, but the design was used only sporadically in medicine and the social sciences until 1950, when four published case-control studies linked smoking and lung cancer. These 1950 studies synthesized the essential elements of the case-control comparison, produced a conceptual shift within epidemiology, and laid the foundation for the rapid development of the case-control design in the subsequent half century.