title: Association of two well-defined polymorphisms in leptin and leptin receptor genes with hypertension and circulating leptin: a meta-analysis.
abstract: OBJECTIVE
  The genes encoding adipose-derived hormone leptin and its receptor (LEPR) are increasingly deemed as hypertension-susceptibility genes. In this meta-analysis, we summarized the association of the II/I polymorphism in leptin gene and Gln223Arg polymorphism in LEPR gene with hypertension and circulating leptin.
  
  
  METHODS
  PubMed and Embase were systematically searched. Data extraction and study quality were assessed in duplicate. Statistical analyses were carried out with the STATA software (v. 11.2).
  
  
  RESULTS
  A total of 11 articles written in English were eligible. Overall analysis identified a significant association between II/I polymorphism I allele and increased risk of hypertension under allelic (odds ratio; 95% confidence interval; P: 1.48; 1.06-2.08; 0.022) and homozygous genotypic (2.27; 1.20-4.29; 0.012) models. The magnitude of the association for II/I polymorphism I allele with hypertension was substantiated in Asians and for essential hypertension under both genetic models. Overall and subgroup analyses failed to reveal any significance for the association between the Gln223Arg polymorphism and hypertension risk. Carriers of Gln223Arg polymorphism Gln/Gln genotype had significantly higher circulating leptin than the Arg/Arg genotype carriers (weighted mean difference; 95% confidence interval; P: 1.61 ng/mL; 0.02-3.20; 0.047), and this significance persisted in essential hypertension subgroup (1.69 ng/mL; 0.02-3.35; 0.047). There were low probabilities of publication bias for the above comparisons.
  
  
  CONCLUSIONS
  Our findings support the contributory role of the II/I polymorphism in leptin gene in the pathogenesis of hypertension, and this role was more evident in Asians and for essential hypertension.
authors.affiliation: Department of Cardiology, Tangshan Gongren Hospital, Tangshan, Hebei, China; Department of Internal Medicine, The Second Hospital of Tangshan, Tangshan, Hebei, China; Graduate School of Hebei United University, Tangshan, Hebei, China.
authors.forename: Ying-Xue
authors.initials: YX
authors.lastname: Li
authors.affiliation: Department of Cardiology, Tangshan Gongren Hospital, Tangshan, Hebei, China. Electronic address: qizhangtangshan@126.com.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Tangshan Gongren Hospital, Tangshan, Hebei, China.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Shang
authors.affiliation: Department of Cardiology, Tangshan Gongren Hospital, Tangshan, Hebei, China.
authors.forename: Yong-Qiu
authors.initials: YQ
authors.lastname: Li
authors.affiliation: Department of Cardiology, Tangshan Gongren Hospital, Tangshan, Hebei, China.
authors.forename: Xiao-Kun
authors.initials: XK
authors.lastname: Liu
authors.affiliation: Department of Cardiology, Tangshan Gongren Hospital, Tangshan, Hebei, China.
authors.forename: Chang-Qing
authors.initials: CQ
authors.lastname: Liu
authors.affiliation: Department of Cardiology, Tangshan Gongren Hospital, Tangshan, Hebei, China.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Liu
authors.affiliation: Department of Cardiology, Tangshan Gongren Hospital, Tangshan, Hebei, China.
authors.forename: Qing-Hua
authors.initials: QH
authors.lastname: Zhang
mesh_terms: D000483:Alleles; D044466:Asian People / Q000235:genetics; D000075222:Essential Hypertension; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D006973:Hypertension / Q000235:genetics*; D020738:Leptin / Q000097:blood* / Q000235:genetics*; D009765:Obesity / Q000235:genetics*; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D054411:Receptors, Leptin / Q000235:genetics*; D044465:White People / Q000235:genetics
chemical_list: D020738:Leptin; D054411:Receptors, Leptin
keywords: Hypertension; Leptin; Leptin receptor; Meta-analysis; Polymorphism