Association between the C242T polymorphism of p22phox gene and ischemic stroke: a meta-analysis

Recently, increasing studies have been focused on the association between the p22phox gene C242T polymorphism and ischemic stroke (IS). However, the results were controversial. As far as we know, there is no previous systematic review or meta-analysis concerning this association. Thus, we conducted this meta-analysis to evaluate this association. The strength of association was evaluated by the odds ratio (OR) with the corresponding 95% confidence intervals (CIs). Heterogeneity was assessed by Q-test and the I(2) statistic. Publication bias was tested using funnel plots and Egger's regression test. Cumulative meta-analysis was performed to assess the trend in pooled OR over time. There was no significant association of the p22phox gene C242T polymorphism with IS in the overall analysis and subgroup analysis by ethnicity and subtypes of IS. However, statistical significance was found in the dominant model (OR: 1.57, 95%CI: 1.18-2.09), codominant model (OR: 1.62, 95%CI: 1.20-2.17) and allelic model (OR: 1.44, 95%CI: 1.11-1.87) among the hospital-based studies. The cumulative meta-analysis also suggested no trend of association between this polymorphism and IS from 2007 to 2011 as more data accumulated over time. Our meta-analysis indicated that the p22phox gene C242T polymorphism is unrelated to the risk of IS in the overall analysis and subgroup analysis by ethnicity and subtypes of IS. However, statistical significance was found in the subgroup analysis by source of controls among the hospital-based studies.