ABSTRACT

This chapter shows how the ideas can be used to collect and collate information on a specific question: ‘can smoking cause lung cancer?’ Right from the introduction of the smoking habit to Europe, there have been doubts about the effect on health; only since the 1920s has evidence been gathered in any purposeful way. Death certificates are not particularly useful since the reported cause of death may be somewhat unreliable; in any case, no indication is given of the deceased’s smoking habits. It is possible to compare lung cancer death rates across countries, sexes, and classes, where there are known to be smoking differences. In the 1920s and 1930s, doctors in the UK and USA began to realize that a very high proportion of their lung cancer patients had been heavy smokers.