Annals of Oncology Advance Access published July 8, 2005 Annals of Oncology doi:10.1093/annonc/mdi312
Original article Smoking and lung cancer in Harbin, northeast China J. Hu1,2, C. Galeone3*, R. Lui2, C. Pelucchi3, C. La Vecchia3,4 & E. Negri3 1
Surveillance and Risk Assessment Division, Centre for Chronic Disease Prevention and Control, Public Health Agency of Canada, Ottawa, Ontario, Canada; Department of Epidemiology, Harbin Medical University, Harbin, China; 3Istituto di Ricerche Farmacologiche ‘Mario Negri’, Milan; 4Istituto di Statistica Medica e Biometria, Universita` degli Studi di Milano, Milan, Italy
2
Received 24 March 2005; revised 4 May 2005; accepted 24 May 2005
Introduction In studies from Western countries, cigarette smoking is responsible for up to 90% of male cases [1, 2] and the risk of lung cancer in smokers is 10 times that for non-smokers. For example, mortality in heavy cigarette smokers was 15 times that of non-smokers in a cohort of British male doctors [3], and in the American Cancer Society Cancer Prevention Study (CPS-I) the lung cancer mortality rate ratios in long-term smokers were >10 for men and >5 for women [4]. Conversely, in several Chinese studies, the risks in smokers are two to three times higher than those in non-smokers [5]. A combined analysis of 15 Chinese case–control studies of lung cancer found a summary odds ratio (OR) of 2.2 for ever-smokers, and population-attributable risks (PARs) of 57% for males and 33% for females [6, 7]. A retrospective proportional mortality study found that, for both sexes, lung cancer death rates at age 35–69 years were about three times greater in smokers than in non-smokers. However, since the rates among non-smokers in different parts of China varied widely, the absolute excesses of lung cancer in smokers also varied [8]. These differences with Western countries may be ascribed to the particular patterns of tobacco consumption (large use of pipe and cigars) [9], as well as to the low average daily tobacco consumption [10, 11] in China before 1980. *Correspondence to: Dr C. Galeone, Istituto di Ricerche Farmacologiche ‘Mario Negri’, Via Eritrea 62, 20157 Milan, Italy. Tel: +39-02-39014577; Fax: +39-02-33200231; E-mail:
[email protected] Ó 2005 European Society for Medical Oncology
The northeastern Chinese areas of Harbin, Jilinshi and Shenyang had very high lung cancer death rates in both smokers and non-smokers in a retrospective mortality study including 1 million deaths, conducted in 98 areas of China [8, 12]. In particular, Harbin had the highest death rates for female smokers (about 3 per 1000) and non-smokers (0.9 per 1000) at ages 35–69 years. This has been attributed to the high indoor pollution related to fumes from domestic heating and cooking [13–15]. As a comparison, in other Chinese areas and in the USA the corresponding rate for non-smoking women was 0.1 per 1000 [8, 16]. In spite of the high rates in non-smokers, in Harbin the risk ratio of lung cancer for smokers was 2.58, similar to the rest of China [8]. A large case–control study of female lung cancer conducted in Shenyang and Harbin found a 2.3-fold increased risk for smokers, with significant trends for number of cigarettes and duration of smoking [17]. In a previous investigation conducted on a population from the same area, the OR for ‡25 cigarettes per day was 3.7 for men [18]. In this paper we further assess the relationship between tobacco smoking and lung cancer using data from a case–control study conducted in Harbin.
Patients and methods The study was conducted between May 1987 and May 1990 in Harbin, Heilongjiang province, northeast China. Both cases and controls had to be resident in Heilongjiang province. In the study province, the 218 newly
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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. Key words: case–control, China, lung cancer, smoking habit
Page 2 of 4 Table 1. Distribution of 218 cases of lung cancer and 436 controls according to age and selected characteristics: Harbin, China, 1987–1990 Cases n
OR (95% CI)a
Controls %
n
%
Age (years)
