Association between Helicobacter pylori infection and nonalcoholic fatty liver disease: a systemic review and meta-analysis.

Although clinical studies have shown possible links of Helicobacter pylori infection with the development of nonalcoholic fatty liver disease (NAFLD), the results remain controversial. The aim of this meta-analysis is to investigate the association between H. pylori infection and NAFLD. A comprehensive search of relevant studies was performed up to November 2018. Data on H. pylori infection in NAFLD patients and controls were extracted. Odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effects model. Twelve studies involving 27 400 NAFLD patients and 60 347 controls were included. The pooled overall OR of H. pylori infection in NAFLD patients compared with controls was 1.36 (95% CI: 1.22-1.53, I=89.6%, P=0.000). Meta-regression and subgroup analysis showed that the sample size and the case-control ratio may have accounted for some of the heterogeneity. When stratified by publication year, the diagnostic method used for H. pylori, and Newcastle-Ottawa Scale scores, the OR remained significant. However, possible publication bias was observed. Of the 12 studies, six had carried out multivariable analysis after adjusting for potential confounders. The pooled results from these studies still indicated a higher risk of NAFLD in patients infected with H. pylori (OR=1.17, 95% CI: 1.01-1.36, I=72.4%, P=0.003). There is a 36% increased risk of NAFLD in patients with H. pylori infection. Further studies are warranted to investigate whether eradication of H. pylori is useful in the prevention and treatment of NAFLD.