title: The meta-analysis of the association of PPARG P12A, C161T polymorphism and coronary heart disease.
abstract: OBJECTIVE
  Two common variations of peroxisome proliferator-activated receptor γ (PPARG), P12A (Pro12Ala, rs1801282), and C161T (His447His, rs3856806), are thought to have an effect on susceptibility to coronary heart disease (CHD), but the results are inconsistent. Therefore, a meta-analysis of published studies was performed.
  
  
  METHODS
  The electronic databases, PubMed, Embase, Web of Science, and CNKI (China National Knowledge Infrastructure) were searched for studies to include in the present meta-analysis (last search was updated on 30 Aug. 2011). Twenty studies testing the association between PPARG gene polymorphisms and CHD were examined: 12 studies of P12A; 8 studies of C161T. Overall and ethnicity-specific summary odds ratios and corresponding 95 % confidence intervals for CHD associated with these polymorphisms were estimated using fixed- and random-effects models. Heterogeneity and publication bias were evaluated. A total of 20 studies including 5,795 cases and 9,069 controls were included in this meta-analysis.
  
  
  RESULTS
  No significant associations were found in carriers of the rare Ala allele of the P12A polymorphism versus the common Pro/Pro genotype among the studies with both of the fixed-effect and random-effect model. In the subgroup analyses by ethnicity, source of control and type of study, no significant risks were found. For PPARG C161T, carriers of the T variant of C161T polymorphism were associated with an increased risk of CHD (OR = 1.182, 95 % CI: 1.023-1.341, P(heterogeneity) = 0.002), and in the stratified analysis by ethnicity and source of controls, the contrast of CT + TT vs. CC all produced significant association in Asian and hospital-based controls (OR = 1.276, 95 % CI: 1.084-1.468, P(heterogeneity) = 0.055; OR = 1.164, 95 % CI: 1.001-1.326, P(heterogeneity) = 0.002),when the fixed-effect model was used. But they were all insignificant with the random-effect model.
  
  
  CONCLUSIONS
  This meta-analysis suggests that the PPARG C161T polymorphism marginally contributes to increased susceptibility to CHD and marginally increased association between PPARG H477H polymorphism and CHD also appeared in Asian and hospital-based controls. But PPARG P12A polymorphism is not associated with CHD risk.
authors.affiliation: Department of Surgery Laboratory, The First Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, P.R. China.
authors.forename: Saidan
authors.initials: S
authors.lastname: Ding
authors.forename: Leping
authors.initials: L
authors.lastname: Liu
authors.forename: Qï-Chuan
authors.initials: QC
authors.lastname: Zhuge
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yu
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Jieya
authors.initials: J
authors.lastname: Xie
authors.forename: Weilong
authors.initials: W
authors.lastname: Hong
authors.forename: Silu
authors.initials: S
authors.lastname: Wang
authors.forename: Yunxiu
authors.initials: Y
authors.lastname: Yang
authors.forename: Bicheng
authors.initials: B
authors.lastname: Chen
mesh_terms: D002681:China / Q000453:epidemiology; D003324:Coronary Artery Disease / Q000453:epidemiology* / Q000235:genetics*; D005260:Female; D056726:Genetic Association Studies; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease / Q000453:epidemiology* / Q000235:genetics*; D006801:Humans; D008297:Male; D047495:PPAR gamma / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D015995:Prevalence; D012307:Risk Factors
chemical_list: D005819:Genetic Markers; D047495:PPAR gamma