Risk factors for esophageal cancer in Shanghai, China. I. Role of cigarette smoking and alcohol drinking.

A population-based case-control study of esophageal cancer was conducted in urban Shanghai involving interviews with 902 cases and 1,552 controls. Risk of esophageal cancer was increased among tobacco smokers and alcohol drinkers. Odds ratios (OR) for smoking were 2.1 and 1.6 for men and women, respectively, and increased with number of cigarettes smoked per day, duration of smoking, number of pack-years and decreasing age at start of smoking. For men who were current alcohol drinkers OR was 1.4, with the excess risk primarily among heavy drinkers. Few women drank alcoholic beverages. The combined effect of heavy smoking and drinking among men was pronounced: OR was 12.0 for those who smoked more than 1 pack per day and drank more than 750 g of ethanol per week. The relation with smoking appeared stronger for cancers of the middle and lower thirds of the esophagus than for the upper third, while patterns of risk for squamous cell carcinoma and adenocarcinoma were similar. Heavy drinking affected all 3 subsites, with increased risks mainly limited to squamous cell carcinoma. Cigarette smoking and alcohol drinking combined accounted for almost 50% of all esophageal cancers among men in Shanghai; among women, 14% of cases were attributed to smoking. Our study confirms that smoking and drinking are important risk factors for esophageal cancer in China, thereby paralleling findings from developed countries.