title: Diabetes mellitus and increased risk of extrahepatic cholangiocarcinoma: a meta-analysis.
abstract: OBJECTIVE
  Diabetes mellitus (DM) has been considered to be relevant to an increased risk of several different types of cancers. However, its relationship with extrahepatic cholangiocarcinoma (ECC) remains unclear.
  
  
  METHODS
  To investigate a quantitative assessment of this relationship, we performed a meta-analysis to evaluate the association between diabetes and the risk of ECC. We identified studies by searching Embase (from 1 January 1974 to 30 June 2012), Medline (from 1 January 1966 to 30 June 2012), and the reference lists of related articles. Summary relative risks (RRs) with corresponding 95% CIs were calculated with a random-effects model.
  
  
  RESULTS
  A total of 9 articles (4 case-control and 5 cohort studies) were included in this study. Compared with those without DM, individuals with DM had an increased risk of ECC (for case-control studies: summary OR=1.61, 95% CI: 1.05-2.49, p=0.063 for heterogeneity; for cohort studies: summary RR=1.61, 95% CI: 1.14-2.29, p=0.005 for heterogeneity). The funnel plot showed no evidence for publication bias concerning DM and the risk of ECC (Egger’s test, p=0.699; Begg’s test, p=0.175).
  
  
  CONCLUSIONS
  These findings strongly reveal the positive link between DM and the increased risk of ECC.
authors: The First Affiliated Hospital of Xinxiang Medical University.
authors: Lan-Fang
authors: LF
authors: Zhang
authors: Hong-Xing
authors: HX
authors: Zhao
mesh_terms: D001650:Bile Duct Neoplasms / Q000453:epidemiology / Q000209:etiology*; D001653:Bile Ducts, Intrahepatic; D018281:Cholangiocarcinoma / Q000453:epidemiology / Q000209:etiology*; D048909:Diabetes Complications / Q000453:epidemiology; D006801:Humans; D012307:Risk Factors