title: Effects of Pro12Ala polymorphism in peroxisome proliferator-activated receptor-γ2 gene on metabolic syndrome risk: a meta-analysis.
abstract: BACKGROUND
  Associations between peroxisome proliferator-activated receptor γ2 (PPARγ2) gene polymorphism and metabolic syndrome risk remained controversial and ambiguous. Thus, we performed a meta-analysis to assess the association between Pro12Ala polymorphism in PPARγ2 gene and metabolic syndrome susceptibility.
  
  
  METHODS
  An electronic literature search was conducted on Medline, OVID, Cochrane Library database, and the China National Knowledge Internet up to March 2013. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to calculate the strength of association in the fixed or random effects model.
  
  
  RESULTS
  Ten studies involving a total of 4456 cases and 10343 controls were included in this meta-analysis. No statistical evidence of association was found between Pro12Ala polymorphism and metabolic syndrome risk in all genetic models (homozygote model: OR=0.83, 95% CI=0.62-1.12; heterozygote model: OR=1.04, 95% CI=0.94-1.14; dominant model: OR=1.02, 95% CI=0.93-1.12; recessive model: OR=0.83, 95% CI=0.62-1.11). No statistical evidence of significant association was observed when stratified by ethnicity, definition of metabolic syndrome, source of control groups and quality score of the selected articles. All in all, the results did not support a major role of the Pro12Ala variant of the PPARγ2 gene in metabolic syndrome risk.
  
  
  CONCLUSIONS
  This meta-analysis suggested that the effect of Pro12Ala polymorphism in PPARγ2 gene may not be related to metabolic syndrome as an entity. However, Pro12Ala may affect the single component of metabolic syndrome. A large, well designed study is required to more adequately assess the role for Pro12Ala polymorphism on metabolic syndrome.
authors.affiliation: Department of Endocrinology, Southern Medical University, Zhujiang Hospital, 253# Industry Road, 510282 Guangzhou, Guangdong, China. Electronic address: zhangruyi133@126.com.
authors.forename: Ruyi
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Endocrinology, Southern Medical University, Zhujiang Hospital, 253# Industry Road, 510282 Guangzhou, Guangdong, China. Electronic address: wangjiao150303@163.com.
authors.forename: Jiao
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, Southern Medical University, Zhujiang Hospital, 253# Industry Road, 510282 Guangzhou, Guangdong, China. Electronic address: yangrui91@163.com.
authors.forename: Rui
authors.initials: R
authors.lastname: Yang
authors.affiliation: Department of Endocrinology, Southern Medical University, Zhujiang Hospital, 253# Industry Road, 510282 Guangzhou, Guangdong, China. Electronic address: 13751822925@163.com.
authors.forename: Jia
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Endocrinology, Southern Medical University, Zhujiang Hospital, 253# Industry Road, 510282 Guangzhou, Guangdong, China. Electronic address: 62782333@163.com.
authors.forename: Rongping
authors.initials: R
authors.lastname: Chen
authors.affiliation: Department of Endocrinology, Southern Medical University, Zhujiang Hospital, 253# Industry Road, 510282 Guangzhou, Guangdong, China. Electronic address: luohaizhao@126.com.
authors.forename: Haizhao
authors.initials: H
authors.lastname: Luo
authors.affiliation: Department of Endocrinology, Southern Medical University, Zhujiang Hospital, 253# Industry Road, 510282 Guangzhou, Guangdong, China. Electronic address: ludenjl@yahoo.com.cn.
authors.forename: Duan
authors.initials: D
authors.lastname: Liu
authors.affiliation: Department of Endocrinology, Southern Medical University, Zhujiang Hospital, 253# Industry Road, 510282 Guangzhou, Guangdong, China. Electronic address: dehongcaizj@163.com.
authors.forename: Dehong
authors.initials: D
authors.lastname: Cai
mesh_terms: D000409:Alanine / Q000235:genetics*; D016022:Case-Control Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D024821:Metabolic Syndrome / Q000235:genetics*; D047495:PPAR gamma / Q000235:genetics*; D011110:Polymorphism, Genetic; D011392:Proline / Q000235:genetics*
chemical_list: D047495:PPAR gamma; D011392:Proline; D000409:Alanine
keywords: Ala; BMI; CI; EGIR; European Group for the study of Insulin Resistance; HB; HDL-C; HOMA; HWE; Hardy–Weinberg equilibrium; Homeostasis Model Assessment; IDF; International Diabetes Federation; LDL-C; MOOSE; Meta-analysis; Meta-analysis of Observational Studies in Epidemiology; Metabolic syndrome; NCEP ATP III; NOS; National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adult; Newcastle–Ottawa Scale; OR; PB; PPARγ; PPARγ2 (gamma2); PRISMA; Polymorphism; Preferred Reporting Items for Systematic Reviews and Meta-analysis; Pro12Ala; SNP; TC; TG; WHO; World Health Organization; alanine; body mass index; confidence interval; high density lipoprotein cholesterol; hospital-based; low density lipoprotein cholesterol; odds ratio; peroxisome proliferator-activated receptor γ2 (gamma2); population-based; single nucleotide polymorphism; substitution of proline to alanine; total cholesterol; triglyceride