Intake of Soy Products and Other Foods and Gastric Cancer Risk: A Prospective Study

Background: Gastric cancer, the most common cancer in the world, is affected by some foods or food groups. We examined the relationship between dietary intake and stomach cancer risk in the Korean Multi-Center Cancer Cohort (KMCC). Methods: The KMCC included 19 688 Korean men and women who were enrolled from 1993 to 2004. Of those subjects, 9724 completed a brief 14-food frequency questionnaire at baseline. Through record linkage with the Korean Central Cancer Registry and National Death Certificate databases, we documented 166 gastric cancer cases as of December 31, 2008. Cox proportional hazard models were used to estimate relative risks (RRs) and 95% CIs. Results: Frequent intake of soybean/tofu was significantly associated with reduced risk of gastric cancer, after adjustment for age, sex, cigarette smoking, body mass index, alcohol consumption, and area of residence (P for trend=0.036). We found a significant inverse association between soybean/tofu intake and gastric cancer risk among women (RR=0.41, 95% CI: 0.22-0.78). Men with a high soybean/tofu intake had a lower risk of gastric cancer, but the reduction was not statistically significant (RR=0.77, 95% CI: 0.52-1.13). There was no interaction between soybean/tofu intake and cigarette smoking in relation to gastric cancer risk (P for interaction=0.268). Conclusions: Frequent soybean/tofu intake was associated with lower risk of gastric cancer.