Helicobacter pylori infection, atrophic gastritis, and risk of pancreatic cancer: A population-based cohort study in a large Japanese population: the JPHC Study.

Helicobacter pylori (H. pylori), an established risk factor for gastric cancer, is suggested to also play a role in the development of pancreatic cancer; however, the association remains inconclusive. We examined this association among Japanese men and women. H. pylori and atrophic gastritis (AG) status were determined serologically, using blood sample collected during health checkups. A total of 20,116 subjects enrolled in the Japan Public Health Center-based Prospective Study Cohort II with available data on H. pylori seropositivity (anti-H. pylori) and AG were followed until the end of 2010. Cox proportional hazards models were used to calculate the hazard ratios (HR) and 95% confidence intervals (CI), using the information from the baseline survey. During 320,470 person-years of follow-up, 119 cases of pancreatic cancer were identified. No statically significant increase or decrease in pancreatic cancer risk was observed for H. pylori and AG status, independently or in combination. In a multivariable-adjusted model, we observed a non-significant decrease in the risk among those who had AG but were anti-H. pylori seronegative (HR 0.57, 95% CI 0.31-1.03). In a stratified analysis, we observed a statistically significant increased risk of pancreatic cancer for AG+ (HR 3.64, 95% CI 1.37-9.66), and AG+/anti-H. pylori- or AG+/anti-H. pylori+ (HR 5.21, 95% CI 1.14-23.87) among current smokers. Non-smokers in all categories of AG and anti-H. pylori showed a non-statistical decrease in the risk. There was no statistically significant interaction between H. pylori infection, AG status, and smoking status. Our findings suggest H. pylori seropositivity and AG, individually or in combination, are not associated with the risk of pancreatic cancer in a general Japanese population. Among current smokers, pancreatic cancer risk increased with AG, regardless of H. pylori infection status.