title: Gamma-glutamyltransferase and risk of cardiovascular mortality: A dose-response meta-analysis of prospective cohort studies.
abstract: BACKGROUND
  Serum gamma-glutamyltransferase (GGT) elevation likely contributes to cardiovascular (CV) mortality, however it has remained unknown whether a dose-response relationship exists between serum GGT and CV mortality.
  
  
  METHODS
  We searched the PubMed, EMBASE, and Cochrane library databases for prospective cohort studies published up to October 2, 2016. Summary hazard ratios (HRs) with their corresponding 95% confidence intervals (CIs) were calculated using a fixed effects model.
  
  
  RESULTS
  Nine prospective studies, including 527,589 participants and more than 7,011 cases, were included in this meta-analysis. For the moderate, high, and highest levels of GGT, the pooled HRs of CV mortality were 1.11 (95% CI = 1.04-1.19), 1.29 (95% CI = 1.21-1.38) and 1.59 (95% CI = 1.47-1.72), respectively (all p < 0.05 as compared to the lowest levels of GGT). Additionally, the HR per incremental increase of GGT by 10 U/L was 1.10 (95% CI = 1.08-1.11). Evidence of a positive relationship with nonlinear trend for GGT elevation with CV mortality in females was found (P = 0.04 for nonlinearity). However, a linear model was better fit to illustrate the GGT-CV mortality among males (P = 0.304 for nonlinearity).
  
  
  CONCLUSIONS
  These findings indicate that serum GGT activity within the reference interval is positively associated with increased risk of CV mortality in a dose-response manner.
authors.affiliation: Department of Infectious Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Junna
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Gerontology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Rehabilitation Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Rongzhong
authors.initials: R
authors.lastname: Huang
authors.affiliation: Department of Gerontology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Xingsheng
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Infectious Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Wenxiang
authors.initials: W
authors.lastname: Huang
mesh_terms: D002318:Cardiovascular Diseases / Q000097:blood* / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D012306:Risk; D012737:Sex Factors; D005723:gamma-Glutamyltransferase / Q000097:blood*
chemical_list: D005723:gamma-Glutamyltransferase