Association of p22phox gene C242T polymorphism with coronary artery disease: a meta-analysis

Introduction: The C242T polymorphism of p22phox gene (rs4673) has been linked to the reduced coronary artery disease (CAD) risk, but results in the published literatures are controversial. A meta-analysis was performed to assess the effect of this polymorphism on the CAD risk.

Methods: A comprehensive search was conducted to identify all studies on the association of p22phox gene C242T polymorphism with CAD risk. The fixed or random effect pooled measure was selected based on the homogeneity test among studies. Heterogeneity among studies was evaluated using Q test and the I(2) of Higgins and Thompson. Meta-regression was used to explore the sources of between-study heterogeneity. Publication bias was estimated using modified Egger's linear regression test proposed by Harbord etal.

Results: We identified 15 published articles including 6273 CAD cases and 5045 controls. In this studied overall and non-Asian populations, we didn't found any significant association of p22phox gene C242T polymorphism with CAD in any of codominant, dominant, and recessive models. Only in Asian population, both fixed effect model (FEM) and random effect model (REM) indicated the significant protective effect both in codominant (FEM: OR=0.771, 95%CI: 0.681-0.873; REM: OR=0.751, 95%CI: 0.607-0.930) and dominant (FEM: OR=0.714, 95%CI: 0.621-0.822; REM: OR=0.694, 95%CI: 0.538-0.895) models with strong evidence for between-study heterogeneity (I(2)=52.6% for codominant and I(2)=56.5% for dominant), but not in recessive model. No evidence of publication bias was detected.

Conclusions: The results suggested a significant heterogeneity across ethnicities about the relationship between the T allele of p22phox gene C242T polymorphism and reduced CAD risk, with a significant protective effect only in Asian population that needs to be confirmed by further studies.