title: Association between β2-Adrenergic Receptor-16Arg/Gly Gene Polymorphism and Chronic Obstructive Pulmonary Disease Risk:Systematic Review and Meta-Analysis.
abstract: BACKGROUND
  The association between β2-adrenergic receptor (ADRB2) -16Arg/Gly polymorphism (rs1042713) and chronic obstructive pulmonary disease (COPD) risk has been investigated in many published studies. However, the results were inconclusive. A meta-analysis was performed to make a more precise estimation of the relationship.
  
  
  METHODS
  The PubMed, EMBASE, ISI web of science, the Cochrane Database of Systematic Reviews, and Chinese databases (CNKI, Wanfang Data, CBM, VIP) were searched for published literature. Odds ratios (OR) with 95% confidence interval (CI) were used to assess the strength of association.
  
  
  RESULTS
  Eleven studies, comprising 1,128 COPD patients and 1,182 controls, were included in the meta-analysis. Overall, there was no significant association between the ADRB2-16Arg/Gly polymorphism and COPD risk in general population. In the stratification analysis by potential confounding variables, significant associations were observed between the ADRB2-16Arg/Gly polymorphism and COPD risk among smoking Asians under the dominant genetic model and allele model (Arg vs. Gly) (dominant model: OR = 1.45, 95% CI = 1.04-2.01, P = 0.311 for heterogeneity, z = 2.22, P = 0.026 for OR; allele model: OR = 1.27, 95% CI = 1.03-1.57, P = 0.209 for heterogeneity, z = 2.20, P = 0.028 for OR), but not in other subgroups.
  
  
  CONCLUSIONS
  This meta-analysis suggested that the ADRB2-16Arg/Gly polymorphism might be a potential risk factor for the development of COPD in smoking Asian populations, but not in European descendents, and tobacco smoking probably increased the genetic susceptibility. More studies with larger sample sizes are needed to validate the results.
authors.affiliation: Dept. of Respiratory Medicine, Zhongnan Hospital of Wuhan University , Wuhan, Hubei 430071, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Dept. of Respiratory Medicine, Zhongnan Hospital of Wuhan University , Wuhan, Hubei 430071, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.affiliation: Dept. of Respiratory Medicine, Zhongnan Hospital of Wuhan University , Wuhan, Hubei 430071, China.
authors.forename: Yifei
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Dept. of Respiratory Medicine, Zhongnan Hospital of Wuhan University , Wuhan, Hubei 430071, China.
authors.forename: Jiong
authors.initials: J
authors.lastname: Yang
keywords: COPD; Meta-analysis; Tobacco smoking; rs1042713; β2-adrenergic receptor