Lifestyle factors, radiation and gastric cancer in atomic-bomb survivors (Japan)

Objective: To examine the association between the incidence of gastric cancer and lifestyle factors such as cigarette smoking, alcohol drinking, and diet as well as atomic bomb radiation exposure. Methods: Longitudinal study including 38,576 atomic-bomb survivors in Hiroshima and Nagasaki, Japan, followed-up between 1980 and 1999. Individual radiation dose was estimated according to the Dosimetry System 1986 (DS86). Lifestyle determinants were based on the responses to a mail survey sent at baseline. 1270 incident carcinomas of gastric cancer were identified during the 485,575 person-years of follow-up. Poisson regression was used to estimate incidence rate ratios. Results: Ionizing radiation exposure, male gender, age, and smoking were significantly associated with an increased risk of stomach cancer. No association was suggested between the frequency of consumption of fruit, vegetables, green tea, and soy products and gastric cancer. Conclusions: In this Japanese population, although radiation and smoking were strong determinants of stomach cancer, no supportive evidence could be shown for the effect of dietary factors.