Helicobacter pylori Seropositivity, ABO Blood Type, and Pancreatic Cancer Risk From 5 Prospective Cohorts

Area of Science:

• Gastroenterology and Oncology
• Infectious Diseases
• Epidemiology

Background:

• Helicobacter pylori (H. pylori) infection is a potential risk factor for pancreatic cancer.
• Certain H. pylori strains, specifically those lacking the cytotoxin-associated gene A (CagA) virulence factor, were hypothesized to be more implicated.
• Blood group antigens on gastric mucosa are involved in H. pylori colonization and non-O blood type is a known pancreatic cancer risk factor.

Purpose of the Study:

• To investigate the association between H. pylori infection, CagA status, and pancreatic cancer risk.
• To examine the interaction between H. pylori seropositivity and non-O blood type in relation to pancreatic cancer risk.

Main Methods:

• A nested case-control study involving 485 pancreatic cancer cases and 1,122 matched controls from five U.S. prospective cohorts.
• Assessed H. pylori and CagA antibody titers in prediagnostic plasma samples.
• Analyzed ABO blood type using genetic polymorphisms or self-report, and employed conditional logistic regression to estimate odds ratios.

Main Results:

• H. pylori seropositivity was not associated with an increased risk of pancreatic cancer (OR 0.83).
• No significant association was found between pancreatic cancer risk and H. pylori infection, regardless of CagA status (CagA-seropositive OR 0.75; CagA-seronegative OR 0.89).
• Non-O blood type was associated with increased pancreatic cancer risk, and this association was consistent regardless of H. pylori seropositivity (P-interaction = 0.51).

Conclusions:

• History of H. pylori infection, as determined by serology, is not associated with pancreatic cancer risk.
• The established risk associated with non-O blood type for pancreatic cancer is independent of H. pylori infection status.