Interaction between Dietary Factors and Helicobacter Pylori Infection in Noncardia Gastric Cancer: A Population-Based Case-Control Study in China

Background: The aim of this study was to investigate the relationships among Helicobacter pylori, dietary factors, and the risk of noncardia gastric cancer in a hospital-based case-control study in China. Methods: A case-control study of noncardia gastric cancer was performed at 3 hospitals in Xi'an, China, between September 2008 and July 2010. Participants were 257 men and women with histologically diagnosed primary noncardia gastric cancer and 514 sex- and age-matched (+/- 5 years) control subjects selected from the communities where the cases were living when diagnosed. A questionnaire was used to obtain information regarding potential risk factors, including diet, and blood samples were obtained to examine H pylori infection status. Results: Positive H pylon status (odds ratio [OR], 3.2; 95% confidence interval [Cl], 0.8-5.9) and high consumption of pickled foods (OR, 27.1; 95%, 8.7-79.1) appeared to increase the risk of noncardia gastric cancer, whereas high consumption of vegetables (OR, 0.3; 95% CI, 0.1-0.89), fruits (OR, 0.2; 95% CI, 0.09-0.81), and soya products (OR, 0.04; 95% CI, 0.01-0.3) appeared to decrease the risk. Consumption of meat, cereals, tubers, eggs, oils, nuts, fish, fresh fruit, and red meat was not clearly associated with risk. Effect modification was observed, such that a relatively high consumption of fruit and vegetables appeared to attenuate the association of H pylori with risk of noncardia gastric cancer (p < 0.05). Conclusions: Our data suggest that noncardia gastric cancer is highly preventable through modifications in dietary habits. Given the prevalence of H pylori infection worldwide, information regarding potential interaction between H pylori and lifestyle factors in gastric cancer development, including the dietary factors examined in our study, may prove valuable in future efforts at prevention.