RISK OF LUNG-CANCER AMONG CIGARETTE AND PIPE SMOKERS IN SOUTHERN CHINA

Studies in Shanghai and in north-east China indicate that cigarette smoking is a major contributor to the high rates of lung cancer in those areas, but doubts persist regarding the influence of cigarette use on lung cancer rates in other areas of China. In addition, the risk of lung cancer associated with other methods of tobacco consumption-in particular, the use of bamboo water-pipes and long-stem pipes-is uncertain. A population-based case-control study of 427 male lung cancer patients residing in a mining area of Southern China and 1,011 controls was carried out to address this and other issues. Of these patients, 63% smoked cigarettes and (water and long-stem) pipes; 17% and 14% smoked only cigarettes or pipes, respectively; and 6% did not smoke. Compared to nonsmokers, smokers of cigarettes only, smokers of pipes only and mixed smokers were at increased risk; OR = 2.6 (95% Cl 1.1-6.2), 1.8 (95% Cl 0.8-4.2) and 4.1 (95% Cl 2.3-9.2), respectively. Risk increased with duration of tobacco use; however, the rate of increase with years of cigarette use was significantly greater than for years of pipe use (p = 0.03). In addition, risks increased 8-fold in the highest quartile of number of cigarettes per day compared to non-cigarette smokers vs. 2.3-fold for the highest quartile of number of liang (50 g) smoked per month compared to non-pipe-smokers; the trends in the ORs differed significantly (p < 0.001). Results suggest that, in this area of China, tobacco use is an important cause of lung cancer, and that smoking cigarettes may be more deleterious than smoking pipes (primarily water pipes).