title: Coffee consumption and risk of the metabolic syndrome: A meta-analysis.
abstract: OBJECTIVE
  The association between coffee consumption and risk of the metabolic syndrome (MetS) remains controversial. For this reason, a meta-analysis including dose-response analysis was conducted to quantitatively summarize the association between coffee intakes and MetS risk.
  
  
  METHODS
  A search was made of PubMed and the China National Knowledge Infrastructure (CNKI) for relevant articles published between 1 January 1999 and 31 May 2015. All observational studies related to the relationship of coffee consumption and risk of MetS were included in the meta-analysis. The result was estimated by a random-effects model, while the dose-response relationship was assessed by a restricted cubic spline model.
  
  
  RESULTS
  Eleven published reports including 13 studies with a total of 159,805 participants were eligible for our meta-analysis. The aggregated result (and 95% CI) for the highest vs lowest category of coffee consumption was 0.872 (0.781-0.975). After excluding one study with a relative risk (RR)<0.300, the aggregated result (and 95% CI) was 0.889 (0.801-0.986). A non-linear relationship was found between coffee consumption and the MetS in the dose-response analysis.
  
  
  CONCLUSIONS
  This meta-analysis suggests that coffee consumption is associated with a low risk of MetS, and further studies to address the question of causality are now needed.
authors.affiliation: Department of epidemiology and health statistics, Qingdao University Medical College, No. 38 Dengzhou Road, 266021 Qingdao, China.
authors.forename: F
authors.initials: F
authors.lastname: Shang
authors.affiliation: Department of epidemiology and health statistics, Qingdao University Medical College, No. 38 Dengzhou Road, 266021 Qingdao, China.
authors.forename: X
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of epidemiology and health statistics, Qingdao University Medical College, No. 38 Dengzhou Road, 266021 Qingdao, China. Electronic address: jiangxiubo2005@126.com.
authors.forename: X
authors.initials: X
authors.lastname: Jiang
mesh_terms: D000328:Adult; D000368:Aged; D002681:China; D003069:Coffee; D004305:Dose-Response Relationship, Drug; D004327:Drinking Behavior; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology*; D008875:Middle Aged; D012307:Risk Factors; D055815:Young Adult
chemical_list: D003069:Coffee
keywords: Coffee; Dose-response analysis; Meta-analysis; Metabolic syndrome; Observational study