A MORTALITY STUDY OF LUNG-CANCER AMONG SWISS PROFESSIONAL DRIVERS - ACCOUNTING FOR THE SMOKING-RELATED FRACTION BY A MULTIVARIATE APPROACH

The mortality due to lung cancer among 'chauffeurs' who have a presuma bly long-term exposure to diesel exhaust fumes, was analysed. As contr ols, men in industrial occupations of similar socio-economic status we re selected. Cases were drawn from the Swiss mortality register for th e years 1979-1983. Person-years were obtained using data from the 1980 census records. These two data files were combined by occupation, age class and socio-economic status. Age adjusted incidence rates were ca lculated applying Poisson regression. To control for tabacco related l ung cancer mortality an indirect adjustment was undertaken. Using info rmation about the smoking habits of the people in the occupations unde r study smoking-attributable lung cancer mortality was accounted for b y incorporating Axelson's technique into multivariate regression model ing. The mortality ratio for lung cancer for chauffeurs with respect t o the controls was 2.27, which is significantly in excess of 1:95% Cl (1.99, 2.58). Other tobacco related diagnoses such as bladder cancer, esophagal cancer and ischemic heart diseases showed excess risks as we ll. After accounting for smoking, a slight but significant increase in lung cancer mortality remained among chauffeurs (mortality ratio 1.48 , 95% Cl:1.30, 1.68). in summary the present results do support the hy pothesis that diesel exhaust is a significant cause of lung cancer.