The ACE insertion/deletion polymorphism and its association with metabolic syndrome.

The angiotensin-1-converting enzyme (ACE) gene has been suggested to be involved in the development of metabolic syndrome (MetS). However, results have been inconsistent. In this study, a meta-analysis was performed to investigate the association between ACE insertion/deletion (I/D) polymorphism and MetS. Published literature from PubMed, EMBASE, and ISI Web of Science databases was searched for eligible publications. All studies assessing the association between ACE I/D polymorphism and MetS were included. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated using a fixed- or random-effects model. Ten studies (1939 cases/2845 controls) for ACE I/D polymorphism were included in this meta-analysis. Most of the studies were performed in whites. The ACE I/D polymorphism was associated with an increased OR of MetS under a dominant model (DD + ID vs II: OR = 1.39; 95% CI, 1.22-1.60; P < .001). Using this model, similar results were found among studies using different ethnic populations, studies using different MetS definitions, and studies with more than 100 cases. This meta-analysis indicated that the D allele of the ACE gene, known to be related to higher levels of angiotensinogen, is associated with an increased OR of MetS. However, given the limited sample size, this association warrants further investigation.