Previous pulmonary diseases and risk of lung cancer in Gansu Province, China

Abstract

Background Although active smoking is well established as the main cause of lung cancer, there is accumulating evidence that history of prior lung diseases may be an independent risk factor for lung cancer. Methods A population-based case-control study in Gansu Province, China identified 886 lung cancer cases (656 male, 230 female) diagnosed between January 1994 and April 1998. A standardized interview collected information on a variety of potential risk factors including a history of physician-diagnosed non-malignant lung diseases (pulmonary tuberculosis, chronic bronchitis/emphysema, asthma, pneumonia), age and year in which each condition was first diagnosed, and any therapy or hospitalization received. Results Pulmonary tuberculosis (odds ratio [OR] = 2.1, 95% CI : 1.4–3.1) and chronic bronchitis/emphysema (OR = 1.4, 95% CI : 1.1–1.8) were associated with increased risk of lung cancer, after adjustment for active smoking and socioeconomic status. The OR for asthma (OR = 1.4, 95% CI : 0.9–2.1) and pneumonia (OR = 1.5, 95% CI : 1.0–2.3) were also elevated. The risk of lung cancer remained significant for pulmonary tuberculosis and chronic bronchitis/emphysema when analysis was limited to the pathologically confirmed cases and self-responders. Conclusions This study provides additional evidence that previous pulmonary tuberculosis and chronic bronchitis/emphysema are causally related to lung cancer, although the precise mechanism is still unclear. The results for asthma and pneumonia, while suggestive of a positive association, did not reach the traditional level of statistical significance and should be interpreted with caution. KEY MESSAGES A population-based case-control study of lung cancer was conducted in Gansu Province, China. Pulmonary tuberculosis and chronic bronchitis/emphysema were significantly associated with lung cancer after adjusting for smoking. Asthma and pneumonia were suggestive of a positive association with lung cancer. History of prior lung disease may be an independent risk factor for lung cancer, although the precise mechanism is unclear.