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 alc ohol drinking and tobacco smoking in Uruguayan men. Methods: A case-co ntrol 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 con ditions related a priori to tobacco smoking and alcohol drinking were considered ineligible for the study. All patients were interviewed sho rtly after admission using a structured questionnaire by two trained s ocial workers. Relative risks, approximated by the odds ratios (OR), w ere 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 conf ounders. Quitters of more than 15 years displayed an OR of 1.1, very c lose to the risk of never-smokers. A younger age at having started smo king was associated with an increased risk, whereas pack-years of ciga rettes showed a significant dose-response. Also, alcohol drinking (par ticularly hard liquor and beer) was associated with an OR of 2.4 (95 p ercent confidence interval = 1.5-3.9), after controlling for the effec t of tobacco, vegetables, and other types of alcohol beverages. Conclu sions: These findings add further support to the role of tobacco and a lcohol in gastric carcinogenesis.