title: Metabolic syndrome and insulin resistance in relation to biliary tract cancer and stone risks: a population-based study in Shanghai, China.
abstract: BACKGROUND
  Serum lipids, diabetes, and obesity, individual components of metabolic syndrome, are associated with biliary tract cancer and stone risk, but the associations of metabolic syndrome or insulin resistance with biliary tract cancers and stones are not well studied.
  
  
  METHODS
  In this population-based case-control study in Shanghai, China (627 biliary tract cancers, 1037 biliary stones, and 959 controls), metabolic syndrome was defined as the presence of any three of the five components, including high waist circumference, high triglycerides, low high-density lipoprotein cholesterol (HDL), high blood pressure, and diabetes. Insulin resistance and β-cell function were assessed, using homeostasis assessment models.
  
  
  RESULTS
  Metabolic syndrome was significantly associated with gallbladder cancer (odds ratio (OR)=2.75, 95% confidence interval (95% CI)=1.82-4.15) and biliary stones (OR=1.64, 95% CI=1.24-2.16), with a significant dose effect with increasing number of metabolic syndrome components (P trend <0.0001). The observed association persisted among subjects without a history of diabetes. The association between insulin resistance and gallbladder cancer was borderline (P trend=0.06). There was a significant inverse association between β-cell function and gallbladder cancer risk (P trend <0.001).
  
  
  CONCLUSIONS
  Our findings suggest that metabolic syndrome and insulin resistance have a role in the aetiology of biliary tract cancers and biliary stones, and if confirmed, they imply that lifestyle control of these factors may lower the risk of biliary stones and biliary tract cancer.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA. sheblf@mail.nih.gov
authors.forename: F M
authors.initials: FM
authors.lastname: Shebl
authors.forename: G
authors.initials: G
authors.lastname: Andreotti
authors.forename: T E
authors.initials: TE
authors.lastname: Meyer
authors.forename: Y-T
authors.initials: YT
authors.lastname: Gao
authors.forename: A
authors.initials: A
authors.lastname: Rashid
authors.forename: K
authors.initials: K
authors.lastname: Yu
authors.forename: M-C
authors.initials: MC
authors.lastname: Shen
authors.forename: B-S
authors.initials: BS
authors.lastname: Wang
authors.forename: T-Q
authors.initials: TQ
authors.lastname: Han
authors.forename: B-H
authors.initials: BH
authors.lastname: Zhang
authors.forename: F Z
authors.initials: FZ
authors.lastname: Stanczyk
authors.forename: A W
authors.initials: AW
authors.lastname: Hsing
mesh_terms: D001661:Biliary Tract Neoplasms / Q000453:epidemiology*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D005260:Female; D042882:Gallstones / Q000209:etiology*; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications*