Prior lung disease and lung cancer risk in an occupational-based cohort in Yunnan, China.

We used the data from a prospective cohort study among tin miners in Yunnan, China to investigate whether prior lung disease is a risk factor for lung cancer. Information on prior lung disease was obtained from baseline questionnaires. The Cox proportional hazards model was used to examine the relationship between prior lung disease and lung cancer risk. From 1992 to 2001, a total of 502 lung cancer cases were confirmed among 9295 cohort participants. Prior chronic bronchitis was associated with an increase in lung cancer risk with an adjusted HR of 1.50 (95% CI: 1.24-1.81). There was an increased risk of developing squamous cell carcinoma in the setting of prior chronic bronchitis and small cell carcinoma in association with asthma with an adjusted HRs of 1.57 (95% CI: 1.19-2.09) and 2.56 (95% CI: 1.38-4.75), respectively. This prospective study provides further evidence that prior chronic bronchitis correlates with increased lung cancer risk, especially for squamous cell carcinoma. Asthma is associated with increased risk of small cell lung carcinoma.