Association of the C242T polymorphism in the NAD(P)H oxidase P22 phox gene with type 2 diabetes mellitus risk: a meta-analysis

Objectives: A number of epidemiological studies have explored the association between NAD(P) H oxidase P22 phox gene C242T (rs4673) polymorphism and susceptibility to type 2 diabetes mellitus (T2DM), but the results are still debatable. Therefore, we conducted a meta-analysis to assess the potential association between the NAD(P) H oxidase P22 phox gene C242T polymorphism and T2DM risk. Methods: Electronic literature searches of the PubMed, Embase, Web of Science, CBMdisc, CNKI and Google Scholar were performed up to June 15, 2013. Additionally, hand searching of the references of identified articles was performed. Data analyses were carried out by Stata 11.0. Results: Seven studies were included in the final meta-analysis, covering a total of 1661 T2DM cases and 1265 controls. The results showed evidence for significant association between the NAD(P) H oxidase P22 phox gene C242T polymorphism and T2DM risk (for T/T vs. T/C: OR - 1.61, 95% CI - 1.14-2.26, p - 0.007; for T/T vs. T/C+C/C: OR = 1.50, 95% CI = 1.10-2.05, p = 0.009). In the subgroup analysis, there was also evidence for significant association between the NAD(P) H oxidase P22 phox gene C242T polymorphism and T2DM risk, either for Asians (T/T vs. T/C+C/C: OR = 1.74, 95% CI = 1.15-2.64, p = 0.009) or for non-Asians (for T allele vs C allele: OR = 1.30, 95% CI = 1.04-1.61, p = 0.02). Conclusions: The present meta-analysis indicates that the NAD(P) H oxidase P22 phox gene 242 T allele might be associated with an increased T2DM risk.