title: Risk of primary liver cancer associated with gallstones and cholecystectomy: a meta-analysis.
abstract: BACKGROUND
  Recent epidemiological evidence points to an association between gallstones or cholecystectomy and the incidence risk of liver cancer, but the results are inconsistent. We present a meta-analysis of observational studies to explore this association.
  
  
  METHODS
  We identified studies by a literature search of PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and relevant conference proceedings up to March 2014. A random-effects model was used to generate pooled multivariable adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Between-study heterogeneity was assessed using Cochran's Q statistic and the I2.
  
  
  RESULTS
  Fifteen studies (five case-control and 10 cohort studies) were included in this analysis. There were 4,487,662 subjects in total, 17,945 diagnoses of liver cancer, 328,420 exposed to gallstones, and 884,507 exposed to cholecystectomy. Pooled results indicated a significant increased risk of liver cancer in patients with a history of gallstones (OR = 2.54; 95% CI, 1.71-3.79; n = 11 studies), as well as cholecystectomy (OR = 1.62; 95% CI, 1.29-2.02; n = 12 studies), but there was considerable heterogeneity among these studies. The effects estimates did not vary markedly when stratified by gender, study design, study region, and study quality. The multivariate meta-regression analysis suggested that study region and study quality appeared to explain the heterogeneity observed in the cholecystectomy analysis.
  
  
  CONCLUSIONS
  Our results suggest that individuals with a history of gallstones and cholecystectomy may have an increased risk of liver cancer.
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China.
authors.forename: Yanqiong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China.
authors.forename: Taijie
authors.initials: T
authors.lastname: Li
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China.
authors.forename: Li
authors.initials: L
authors.lastname: Xie
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Qin
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Li
mesh_terms: D016022:Case-Control Studies; D002763:Cholecystectomy / Q000009:adverse effects*; D015331:Cohort Studies; D000068598:Data Accuracy; D005260:Female; D042882:Gallstones / Q000150:complications* / Q000473:pathology / Q000601:surgery; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D008297:Male; D016017:Odds Ratio; D012306:Risk