ABSTRACT
At the beginning of the 20th century, the death toll due to lung cancer was on the rise and the search for possible causes began. For lung cancer in pit workers, animal experiments showed that the so-called ‘Schneeberg lung disease’ was induced by radiation. But this could not explain the increasing incidence of lung cancer in the general population. The identification of possible risk factors was a challenge for epidemiology and statistics, both disciplines being still in their infancy in the 1920s and 1930s. The first modern controlled epidemiological study on the effect of smoking
on lung cancer was performed by Franz Hermann Mu¨ller as part of his dissertation at the University of Cologne in 1939. The results were published a year later (Mu¨ller, 1940). Mu¨ller sent out questionnaires to the relatives of people who had recently died of lung cancer, asking about the smoking behavior and its intensity of the deceased relative. He also sent the questionnaire to healthy controls to obtain information about the smoking behavior in a control group, although it is not clear how this control group was defined. The number of lung cancer patients and healthy controls in five different groups (nonsmokers to extreme smokers) are given in Table 18.1.
