Tobacco smoking and alcohol drinking as risk factors for stomach cancer: a case-control study in Uruguay

Objectives: To estimate the risk of stomach cancer associated with alcohol drinking and tobacco smoking in Uruguayan men. Methods: A case-control including 331 cases and 622 controls was conducted in Montevideo, Uruguay, during the period 1992-96. The study was restricted to men, and both cases and controls were patients admitted to the major four hospitals in Montevideo. Response rates were high and similar for both series (92.8 for cases and 92.6 percent for controls). Controls were frequency-matched to cases on age and residence, and patients with conditions related a priori to tobacco smoking and alcohol drinking were considered ineligible for the study. All patients were interviewed shortly after admission using a structured questionnaire by two trained social workers. Relative risks, approximated by the odds ratios (OR), were estimated by unconditional logistic regression in models including major potential confounders. Results: Smoking duration was associated with an increased risk of 2.2 for smokers of more than 50 years, with a significant dose-response pattern, after controlling for major confounders. Quitters of more than 15 years displayed an OR of 1.1, very close to the risk of never-smokers. A younger age at having started smoking was associated with an increased risk, whereas pack-years of cigarettes showed a significant dose-response. Also, alcohol drinking (particularly hard liquor and beer) was associated with an OR of 2.4 (95 percent confidence interval = 1.5-3.9), after controlling for the effect of tobacco, vegetables, and other types of alcohol beverages. Conclusions: These findings add further support to the role of tobacco and alcohol in gastric carcinogenesis.