Public Health · 1954
British Doctors Study (Doll and Hill prospective cohort)
In 1950, Richard Doll and Austin Bradford Hill published a case-control study showing that lung cancer patients reported heavier smoking histories than controls. It was suggestive but methodologically vulnerable: patients with a serious illness might recall their habits differently, and the design could not measure mortality rates directly. Hill, one of the leading biostatisticians of the era, knew that a prospective cohort study would answer the objection. In October 1951, they mailed questionnaires to all physicians on the British Medical Register.
About 40,700 doctors responded, providing detailed smoking histories. Doll and Hill then tracked deaths through the General Register Office, a straightforward process because British physicians were a small, well-documented population whose deaths were reliably recorded and certified. The 1954 report in the BMJ presented findings from just the first years of follow-up. Even in that short interval, lung cancer mortality rose sharply with the number of cigarettes smoked daily, with heavy smokers carrying substantially higher risk than lifelong nonsmokers.
The prospective design neutralized the main objection to the earlier case-control work. Smoking histories were recorded before any participant developed lung cancer, so there was no possibility that diagnosis had colored self-reporting. Death rates could be calculated directly per 100,000 person-years of follow-up, a metric the case-control approach could not provide. The study also separated lung cancer deaths from deaths by other causes, addressing the concern that smokers might simply die of other diseases before lung cancer appeared.
Doll continued following the cohort for fifty years. The final report, published in 2004 after most of the original doctors had died, showed that men born around 1920 who smoked throughout adult life lost approximately ten years of life expectancy compared to lifelong nonsmokers. Those who stopped smoking before age 35 recovered close to normal life expectancy; stopping at 50 recovered about half the lost years. These dose-response and cessation-benefit figures became foundational numbers in tobacco policy.
The British Doctors Study ran in parallel with the U.S. evidence accumulating through the 1950s, and both fed into the 1964 U.S. Surgeon General's report, which formally declared smoking a cause of lung cancer. Hill later codified the criteria by which epidemiological associations could be evaluated for causality, published in 1965, partly drawing on what he and Doll had worked through across this long cohort.
Key People
- Richard Doll — Epidemiologist; co-designed and led the cohort over five decades.
- Austin Bradford Hill — Statistician and epidemiologist; co-designed the study and its analysis.
BMJ, 1954
Related landmarks
- 1956 · Water Fluoridation (Grand Rapids study, 10-year results) (Public Health)
- 1950 · Doll and Hill smoking and lung cancer case-control study (Public Health)
- 1961 · Framingham Heart Study: the "risk factor" concept (Public Health)
- 1964 · Surgeon General's Report on Smoking and Health (Public Health)