Air pollution and lung cancer in Trieste, Italy.

To investigate the relation between air pollution and histologic type of lung cancer, the authors conducted a case-control study among men who had died in Trieste, Italy, from 1979 to 1981 and from 1985 to 1986. Through the local autopsy registry, 755 cases of lung cancer and 755 controls were identified. Information on smoking habits, occupation, and place of residence was obtained from each 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. Logistic regression was used to evaluate the effect of residence and air pollution on lung cancer 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 (95% CI 1.0-2.2) for residents of the center of the city and 1.4 (95% CI 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.