Smoking and lung cancer in Harbin, northeast China

Background: We studied the relationship between smoking and lung cancer risk in Harbin, Heilongjiang province, northeast China, an area with a very high baseline risk of lung cancer in both sexes, using data from a case-control study of lung cancer conducted between 1987 and 1990. Patients and methods: Cases were 218 patients with incident, histologically confirmed lung cancer and controls were 436 patients admitted to the same hospital with non-neoplastic and non-lung diseases. Results: Compared with never-smokers, the multivariate odds ratio (OR) for current smokers was 3.47 [95% confidence interval (CI) 2.31-5.20], and for ex-smokers 1.53 (95% CI 0.81-2.87). Lung cancer risk increased by 20% (95% CI 14% to 28%) for an increment of 5 years in smoking duration, and by 29% (95% CI 15% to 45%) for an increment of five cigarettes per day. The OR for smokers reporting occupational exposure to selected known or likely lung carcinogens was 7.22, compared with nonsmokers without occupational exposure. Conclusions: This study further confirms that cigarette smoking is a strong determinant of lung cancer also in this high-risk area of northeast China