Association between Helicobacter pylori and pancreatic cancer risk: a meta-analysis

Gastric colonization with Helicobacter pylori (H. pylori) has been implicated in the pathogenesis of pancreatic cancer, but results of epidemiological studies have been inconclusive. We analyzed data from the Queensland Pancreatic Cancer Study, an Australian population-based case-control study, and incorporated our findings into an updated meta-analysis. Blood samples were obtained from 580 patients and 626 controls, and enzyme-linked immunosorbent assay kits were used to determine seropositivity to H. pylori and its virulence protein, cytotoxin-associated gene A (CagA). Odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated using logistic regression. Results were incorporated into a meta-analysis along with results of studies identified through systematic literature review. Adjusted ORs and 95 % CIs were calculated using the DerSimonian and Laird random-effects model. No overall association was observed between H. pylori seropositivity and risk of pancreatic cancer (OR 1.00; 95 % CI 0.74-1.35). Nonsignificantly decreased pancreatic cancer risk was observed with CagA seropositivity (OR 0.74; 95 % CI 0.48-1.15) and increased risk with CagA-negative H. pylori seropositivity (OR 1.23; 95 % CI 0.83-1.82). Ten studies were included in the meta-analysis. There was no significant overall association between H. pylori seropositivity and pancreatic cancer risk (OR 1.13; 95 % CI 0.86-1.50), but evidence of CagA strain-specific associations (OR 0.78; 95 % CI 0.67-0.91 and OR 1.30; 95 % CI 1.02-1.65 for CagA-positive and CagA-negative strains, respectively). Our results provide further evidence for the existence of strain-specific associations between H. pylori and pancreatic cancer.