The association of angiotensin-converting enzyme gene insertion/deletion polymorphisms with OSA: a meta-analysis.

Obstructive sleep apnoea (OSA) is an independent risk factor for hypertension. Increased angiotensin-converting enzyme (ACE) activity may be a possible promoting mechanism with different ACE insertion/deletion (I/D) genotypes influencing this activity. Studies investigating the association of ACE I/D polymorphisms with OSA have shown conflicting results. We aimed to undertake a meta-analysis of existing studies exploring the association of ACE I/D polymorphisms with the risk of OSA and hypertension. 10 studies were included in a random effects meta-analysis, comprising 1,227 OSA subjects and 1,227 controls. The effect size was measured using the odds ratio. The risk of having OSA in carriers of the D allele was 0.92 (95% CI 0.69-1.23). There was statistically significant heterogeneity across the studies (I(2)=42%, p=0.08 and I(2)=74%, p<0.0001 for genotype and allele frequency, respectively). The association of D allele frequency with the risk of OSA remained nonsignificant after stratification based on ethnicity, source of population sample, and the presence of hypertension. Subgroup analysis failed to show any influence of genotype and allele frequency on OSA severity. This meta-analysis revealed no association between the ACE I/D polymorphisms and OSA susceptibility.