A cohort analysis of lung cancer and smoking in British males.

Lung cancer mortality in England and Wales among males in the age group 25 to 84 over the years 1941 to 1975 was analyzed. Using cigarette consumption information from the Tobacco Research Council and a statistical model, relative and attributable risks were estimated. The lung cancer deaths could be partitioned into deaths among smokers and deaths among nonsmokers; 88% of total male deaths during the study period could be attributed to smoking. Whereas the mortality rate among smokers increased over the entire span of the analysis, the rate among nonsmokers rose gradually until 1956-1960 and then declined until 1971-1975. The beginning of the decline was coincident with the implementation of the Clean Air Act of 1956. In order to address possible systematic biases in the smoking data, Monte Carlo simulations were performed.