[A case-control study of lung cancer risk factors in Xuanwei]

In Xuanwei County, Yunnan Province, lung cancer mortality is the highest in China. The former studies showed that indoor burning of "smokey" coal was an important cause for high incidence of Xuanwei lung cancer. The 1:Mi matched case-control study was undertaken to examine the association with other risk factors such as smoking. 110 cases of primary lung cancer newly diagnosed and 426 controls individually matched were interviewed. Conditional logistic regression was employed to examine the effect modification and to control confounding. The analytic results showed that smoking was one of the risk factors of Xuanwei male lung cancer. No relation was found between passive smoking and female lung cancer. The association was observed for familial history of lung cancer.