Associations of TNFα-308G/A and TNFα-238G/A Polymorphisms with Ischemic Stroke in East Asians and Non-East Asians: A Meta-Analysis

Aims: Two well-characterized polymorphisms in the tumor necrosis factor (TNF) gene, TNF alpha-308G/A and TNF alpha-238G/A, are thought to play important roles in the etiology and pathogenesis of ischemic stroke. Due to ethnic diversity, studies of the associations between these polymorphisms and ischemic stroke are inconclusive. Thus, we conducted a meta-analysis to derive more precise estimates of these associations in East Asians and non-East Asians. Materials and Methods: We searched relevant publications in the PubMed, Embase, and Medline databases. A total of 18 studies with 8075 patients and 8217 controls were included. The odds ratios (OR) and 95% confidence intervals (CIs) were evaluated to identify associations. Results: Analyses of the full dataset failed to identify any significant association between ischemic stroke and the TNF alpha-308G/A (A vs. G: OR = 0.86, 95% CI: 0.72-1.02, p = 0.08) or TNF alpha-238G/A (A vs. G: OR = 0.94, 95% CI: 0.67-1.32, p = 0.72) polymorphism. In subgroup analysis by ethnicity, TNF alpha-308G/A was found to be a protective factor (A vs. G: OR = 0.69, 95% CI: 0.56-0.85, p = 0.01) against ischemic stroke in the East Asians. No significant association was detected between ischemic stroke risk and TNF alpha-238G/A in the East Asians (A vs. G: OR = 0.82, 95% CI: 0.57-1.16, p = 0.26) or non-East Asians (A vs. G: OR = 1.61, 95% CI: 0.90-2.88, p = 0.11). Conclusions: The results of this meta-analysis suggest that there is no significant relationship between ischemic stroke and TNF alpha-308G/A or TNF alpha-238G/A. However, according to subgroup analysis of East Asians, TNF alpha-308G/A is a protective factor against ischemic stroke.