title: Association of ACE I/D polymorphism with obstructive sleep apnea susceptibility: evidence based on 2,228 subjects.
abstract: BACKGROUND
  Whether the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene increases susceptibility to obstructive sleep apnea (OSA) is controversial and still undetermined. Therefore, this meta-analysis was performed to systematically assess the possible association between them.
  
  
  METHODS
  The OVID, Medline, Embase, Web of Science, CNKI, and Wangfang databases were searched to identify eligible studies focusing on the association between ACE polymorphism I/D and susceptibility to OSA.
  
  
  RESULTS
  A total of 2,228 subjects from nine studies were subjected to meta-analysis. Overall, ACE polymorphism I/D had no statistically significant association with increased OSA risk under all genetic models (P > 0.05). In the subgroup analysis by ethnicity or study design, still no significant associations were found for all genetic models (P > 0.05). However, ACE polymorphism I/D was significantly associated with susceptibility to OSA with hypertension in Asians under heterozygous comparison and dominant model. The ID genotype carriers and D allele carriers (ID + DD) were about 53% less likely (odds ratio (OR) = 0.47, 95% confidence interval (CI) = 0.29-0.74; P = 0.001) and about 52% less likely (OR = 0.48, 95% CI = 0.24-0.99; P = 0.047), respectively, to have OSA with hypertension compared to carriers of the II genotype.
  
  
  CONCLUSIONS
  ACE polymorphism I/D had no statistically significant association with increased OSA risk, but the II genotype of ACE may be a risk factor for OSA with hypertension in Asians. OSA cases who develop hypertension may derive from a different mechanism compared to essential hypertension. Studies with large sample size and representative population are warranted to verify this finding.
authors.affiliation: Department of Otorhinolaryngology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Xuhui District, Shanghai, 200031, China.
authors.forename: Hai
authors.initials: H
authors.lastname: Lin
authors.forename: Dong
authors.initials: D
authors.lastname: Lin
authors.forename: Chunquan
authors.initials: C
authors.lastname: Zheng
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Lian
authors.initials: L
authors.lastname: Fang
mesh_terms: D000483:Alleles; D006580:Genetic Carrier Screening; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D054643:INDEL Mutation; D011110:Polymorphism, Genetic / Q000235:genetics*; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000235:genetics*