A case-control study of the relationships among silica exposure, gastric cancer, and esophageal cancer

Background: We examined the effect of silica exposure on gastric and esophageal cancer mortality using a cancer control series in a population setting. Methods: Cases and controls were restricted to male subjects and were drawn from death certificates in the Tobi area of Japan. A control group was selected from a series of deaths due to colon cancer, and cancers of other organs. The Japanese death certificate system is comprehensive because all deaths must be reported to the local office and death certificates are written by medical doctors. Age and smoking habits adjusted the Mantel-Haenszel odds ratios were estimated. Results: For gastric cancer, the age-, smoking-adjusted odds ratios were 1.22 (95% CI 0.74-2.01)for colon cancer and the other cancer control for silica exposure work, and 1.36 (95% CI 0.76-2.43) for silicosis. For esophageal cancer, the age- and smoking-adjusted odds ratios were 1.53 (95% CI 0.59-3.96) for the cancer control for silica exposure, and 2.33 (95% CI 0.87-6.23) for silicosis, respectively. Conclusions: The results suggest that gastric and esophageal cancer were related to silica exposure and silicosis in the study area, although they did not reach a statistically significant level because of the small sample size. The estimated odds ratios were higher for esophageal cancer and silicotic patients.