Grant: Operating Grant

Lung cancer is the most common cancer in Canada, accounting for 25% of all cancer deaths. Prevention of lung cancer depends on the discovery and elimination of its causes. Each cancer case results from the conjuncture of a complex of circumstances (e.g., genetic predisposition, environmental exposures, lifestyle habits) which combine over a lifetime to initiate cancers. Cigarette smoking is the single most important cause of lung cancer. Since it has proven so hard to eliminate smoking, it is very important to identify other modifiable causes. Apart from smoking, there are several recognized or suspected lung carcinogens in the occupational milieu and there are several suspected non-occupational risk factors as well, such as alcohol intake, domestic radon, and urban air pollution. In 1996 we undertook a large study of lung cancer whose aim was to elucidate environmental causes of lung cancer. All lung cancer cases occurring in Montreal from 1996 to 1998 were approached, as well as a representative sample of people in the general population. Interviews were carried out with 1211 cases and 1539 controls. The questionnaire focused on lifetime occupational history, but also included detailed info on many other factors. The occupational history was subsequently evaluated to infer a list of occupational exposures. The statistical challenge is to compare the cases with the controls to determine which factors, if any, occurred more often among cases than among controls, and that might be causally related to lung cancer. This is a lengthy and painstaking process. We have started working our way through the long list of about 600 different variables at our disposal, and this has resulted in a number of results and publications. The purpose of the present application is to extend the comprehensive program of statistical analysis and reporting of this study. We will continue to make significant contributions to the identification of modifiable risk factors for lung cancer.