Association Between ABO Blood Groups and Helicobacter pylori Infection: A Meta-Analysis

There is no consensus among the existing literature on the relationship between ABO blood groups and risk of Helicobacter pylori infection. However, histo-blood group carbohydrates are proposed to influence the risk of acquiring this pathogen via effects on adhesion to the gastric mucosa. The objective of this meta-analysis was to evaluate the association between ABO blood groups and H . pylori infection. All relevant epidemiological studies published in English (up to October 2017) was retrieved through an extensive systematic literature search of MEDLINE/PubMed databases. Pooled estimates of effects were obtained through the use of fixed and random effects meta-analyses. Individuals with O blood group were more likely to be infected with H . pylori (pooled odds ratio (OR) 1.163; 95% confidence interval (CI) 1.074–1.259; P < 0.001). While individuals with B and AB blood group were less likely to be infected with H . pylori (OR 0.831; 95% CI 0.738–0.935; P = 0.002 and OR 0.709; 95% CI 0.605–0.832; P < 0.001, respectively). The results from this meta-analysis of observational studies suggest an estimated 16.3% increased odds of H . pylori infection amongst individuals with the O blood group. If this observed association is causal, a better understanding of the underlying mechanisms could provide indications to potential prevention strategies for H . pylori infection.