title: Hepatitis B virus infection and risk of gallstones: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Gallstone disease and its complications are common, particularly in Western populations. Recent studies have reported a significantly increased risk of gallstones among hepatitis C virus-infected patients. However, the data on patients with hepatitis B virus (HBV) infection are still limited. This meta-analysis was carried out with the aim of summarizing all available evidence.
  
  
  METHODS
  A literature search was performed using MEDLINE and the EMBASE database from inception to May 2016. Studies that reported relative risks, odd ratios, or hazard ratios comparing the risk of gallstones among HBV-infected patients versus patients without HBV infection were included. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse-variance method.
  
  
  RESULTS
  Nine studies fulfilled our eligibility criteria and were included in the analysis. We found no significant association between HBV infection and the risk of gallstones, with a pooled OR of 1.10 (95% CI, 0.91-1.33). The statistical heterogeneity was moderate, with an I of 69%. Subgroup analysis was carried out. The pooled OR of cross-sectional studies was 1.01 (95% CI, 0.91-1.12; I 0%), whereas the pooled OR of case-control studies was 1.53 (95% CI, 0.85-2.74; I 80%).
  
  
  CONCLUSIONS
  A significant association between HBV infection and the risk of gallstones was not observed in this study.
authors.affiliation: aDepartment of Internal Medicine, Bassett Medical Center, Cooperstown, New York bDepartment of Gastroenterology and Hepatology, University of Nebraska Medical Center, Omaha, Nebraska cDivision of Rheumatology, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota, USA dDepartment of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai eDivision of Rheumatology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Karn
authors.initials: K
authors.lastname: Wijarnpreecha
authors.forename: Charat
authors.initials: C
authors.lastname: Thongprayoon
authors.forename: Panadeekarn
authors.initials: P
authors.lastname: Panjawatanan
authors.forename: Wuttiporn
authors.initials: W
authors.lastname: Manatsathit
authors.forename: Patompong
authors.initials: P
authors.lastname: Ungprasert
mesh_terms: D042882:Gallstones / Q000453:epidemiology*; D019694:Hepatitis B, Chronic / Q000453:epidemiology*; D006801:Humans; D016017:Odds Ratio; D016016:Proportional Hazards Models; D012307:Risk Factors