Cohort studies: history of the method. II. Retrospective cohort studies

Conclusion What then of the future? Cohort studies in the original sense of the generation studies introduced by Andvord in 1930³⁵ helped our understanding of the spread of tuberculosis and the aetiology of several cancers, but they are now of limited application and I doubt if they have much more to teach us. Cohort studies in the modern sense, both prospective and retrospective, have established themselves as essential tools for epidemiological research. The nested case-control study and the use of biomarkers, which will in the course of time involve the techniques of molecular biology, provide us with powerful weapons for testing hypotheses about both the genetic and environmental causes of disease and cohort studies have, I suspect, an even more important part to play in the future of medical research than they have had in the past.