Hepatitis B virus infection is associated with gastric cancer in China: an endemic area of both diseases

Background: Hepatitis B virus (HBV) infection was demonstrated to be a risk factor of several cancers of the digestive system. In addition, liver cirrhosis, which could possibly result from chronic HBV infection, was associated with a higher risk of gastric cancer. However, the association of HBV infection and gastric cancer has not been investigated. Methods: A retrospective case-control study with 580 cases and 580 controls matched for age, sex and year of diagnosis was conducted. The associations between gastric cancer and HBV infection were explored with univariate and multivariate unconditional logistic regression analysis. Results: Hepatitis B surface antigen (HBsAg) was positively associated with gastric cancer (AOR (95% CI): 1.49 (1.06-2.10)). This association remained significant in patients without family history of gastric cancer (AOR (95% CI): (1.06-2.11)). For HBsAg-negative population, being anti-HBc positive/anti-HBs negative, which possibly indicated occult HBV infection, was also found to have some associations with gastric cancer. In addition, some synergistic effects between HBV infection and blood type A in gastric cancer were identified. Conclusions: The HBV infection was positively related with gastric cancer, especially for patients without family history of gastric cancer. Further prospective studies are warranted to confirm this relationship.