title: Association between angiotensin-converting enzyme I/D polymorphism and asthma risk: a meta-analysis involving 11,897 subjects.
abstract: BACKGROUND
  Genetic susceptibility to asthma has been a research focus in the scientific community. Several studies have been conducted in recent years to evaluate the risk of asthma and insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE). However, the results remain conflicting rather than conclusive.
  
  
  METHODS
  We carried out a search in Medline, EMBASE, and Chinese National Knowledge Infrastructure (CNKI) database for relevant studies. Data were extracted using a standardized form and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of the association.
  
  
  RESULTS
  Our meta-analysis on 11,897 subjects from all available studies showed that the DD genotype was associated with increased asthma risk than those with the II (OR = 1.59, 95% CI = 1.20-2.12) or ID/II (OR = 1.62, 95% CI = 1.24-2.10) genotype. Stratified analyses by ethnicity (Europeans and Asians) and age (adults and children) obtained statistically similar results in the two genetic models. In the subgroup analysis by source of controls, the DD genotype was associated with a significantly elevated risk of asthma among population-based controls (DD vs. II: OR = 2.27, 95% CI = 1.45-3.56) but not hospital-based controls (DD vs. II: OR = 1.18, 95% CI = 0.93-1.49).
  
  
  CONCLUSIONS
  This meta-analysis provides strong evidence that the I/D polymorphism of ACE is associated with asthma risk. Additional well-designed large studies were required for the validation of our results, especially in African populations.
authors: Department of Respiratory Medicine, Affiliated Hospital, Medicine College, Ningbo University, Ningbo, China.
authors: Qun-Li
authors: QL
authors: Ding
authors: Shi-Fang
authors: SF
authors: Sun
authors: Chao
authors: C
authors: Cao
authors: Zai-Chun
authors: ZC
authors: Deng
mesh_terms: D001249:Asthma / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D011110:Polymorphism, Genetic; D012306:Risk
chemical_list: D007703:Peptidyl-Dipeptidase A