The angiotensin-converting enzyme insertion/deletion polymorphism and susceptibility to rheumatoid arthritis, vitiligo and psoriasis: A meta-analysis

Introduction: The purpose of this study was to examine whether the insertion (I) and deletion (D) of angiotensin-converting enzyme (ACE) polymorphism confers susceptibility to psoriasis, vitiligo and rheumatoid arthritis (RA). Materials and methods: A meta-analysis was conducted on the association between the ACE I/D polymorphisms and psoriasis, vitiligo and RA. Results: Fifteen studies comprising five on psoriasis, five on vitiligo and five on RA were available for the meta-analysis consisting of 2094 cases and 2871 controls. Meta-analysis of the DD+ID genotype showed significant associations with psoriasis (odds ratio (OR) 0.753, 95% confidence interval (CI) 0.601-0.921, p = 0.006). Meta-analysis showed no association between vitiligo and the ACE I/D polymorphism. Meta-analysis of the DD+ID genotype showed an association with RA (OR 2.199, 95% CI 1.379-3.506, p = 0.001). Ethnicity-specific meta-analysis of the D allele showed no association with psoriasis in Europeans, and vitiligo in South Asians. However, subgroup analysis by ethnicity revealed a significant association between the D allele and RA in Arab populations (OR 2.697, 95% CI 1.803-4.034, p = 1.3 × 10^-5). Conclusions: Our meta-analysis demonstrates that the ACE I/D polymorphism is associated with susceptibility to RA, especially in Arab populations.