Smoking, alcohol and gastric cancer risk in Korean men: the National Health Insurance Corporation Study

We investigated the risk of gastric cancer by subsite in relation to cigarette smoking and alcohol in a large population-based cohort of 669 570 Korean men in an insurance plan followed for an average 6.5 years, yielding 3452 new cases of gastric cancer, of which 127 were cardia and upper-third gastric cancer, 2409 were distal gastric cancer and 1007 were unclassified. A moderate association was found between smoking, cardia and upper-third (adjusted relative risk (aRR) 2.2; 95% confidence interval (CI) 1.4–3.5) and distal cancers (aRR=1.4; 95% CI=1.3–1.6). We also found a positive association between alcohol consumption and distal (aRR=1.3; 95% CI=1.2–1.5) and total (aRR=1.2; 95% CI=1.1–1.4) gastric cancer. Combined exposure to high levels of tobacco and alcohol increased the risk estimates further; cardia and upper-third gastric cancers were more strongly related to smoking status than distal gastric cancer.