A case-control study of stomach cancer and its genesis in relation to alcohol consumption, smoking, and familial cancer history.

A case-control study of stomach cancer and its genesis has been conducted in relation to alcohol consumption, cigarette smoking, and familial cancer history. Two hundred and ninety-four cancer cases, discovered by mass screening and histologically verified after endoscopic examination, have been compared with 588 randomly selected controls, who received the same early detection program and were verified as being free of the disease. No statistically significant association was observed between the development of stomach cancer and alcohol consumption or familial cancer history. However, the development of stomach cancer was found to have a positive correlation with smoking (relative risk for those who smoke less than 19 cigarettes/day, 3.56: 95% confidence interval, 2.39 to 5.31; relative risk for those who smoke more than 20 cigarettes/day, 2.58: 95% confidence interval, 1.60 to 4.17). The results of this study suggest that cigarette smoking appears to have a more harmful effect on the development of stomach cancer than either alcohol consumption or a familial history of cancer. The high relative risk of smoking revealed by this study implies that further research on the effects of smoking in the development of stomach cancer would be desirable.