Are Helicobacter pylori and other Helicobacter species infection associated with human biliary lithiasis? A meta-analysis

BACKGROUND: Since the isolation of Helicobacter species in biliary system, a hypothetical question was raised about the role of these agents in the development of cholelithiasis. This meta-analysis is to explore the association between the Helicobacter infection and biliary lithiasis. METHODOLOGY/PRINCIPAL FINDINGS: A systematic literature search was performed to identify all eligible articles. Meta-analysis which was carried out using odds ratio and random effect model, 95% confidence intervals for odds ratio was calculated. Quantitative assessment of heterogeneity was explored by chi-square test with significance set at P value 0.10 and was measured using I(2) statistic. Eighteen studies published between 1998 and 2011 were finally eligible for meta-analysis. H. pylori, H. bilis, H. hepaticus, H. pullorum and H. ganmani were studied. With heterogeneity (I(2) = 69.5%, P