[Comparison of epidemiologic methods in a case-control study of lung cancer and air pollution in Trieste, Italy]

To investigate the relationship between air pollution and histologic type of lung cancer we conducted a case-control study among deceased men in Trieste, Italy. 755 cases of lung cancer and 755 controls were identified through the local autopsy registry. Information on smoking habits, occupation and place of residence was obtained from the subject's next-of-kin. Air pollution at the residence of each subject was estimated from the average value of total particulate at the nearest monitoring station. Spatial models and logistic regression were used to evaluate the effect of residence and air pollution on LC after adjustment for age, smoking habits, likelihood of exposure to occupational carcinogens and social group. The risk of lung cancer increased with increasing level of air pollution for all types of lung cancer combined (P = 0.022), for small cell carcinoma (P = 0.016) and for large cell carcinoma (P = 0.049). Compared with inhabitants of the residential area, residents of the rural area had a relative risk (RR) of 0.6 (95% confidence interval (CI): 0.4-1.0). The RR was 1.5 (1.0-2.2) for residents of the center of the city and 1.4 (1.0-2.1) for residents of the industrial area. In the center of the city the excess risk was almost completely restricted to small cell carcinoma (RR = 2.0) and to large cell carcinoma (RR = 2.6). In the industrial area the risk was increased especially for adenocarcinoma (RR = 2.1). These results provide evidence that air pollution is a moderate risk factor for certain histologic types of lung cancer.