Associations of tumor necrosis factor-α polymorphisms with the risk of asthma: a meta-analysis.

OBJECTIVE: Recently, potential correlations between tumor necrosis factor-α (TNF-α) polymorphisms and asthma were investigated by some pilot studies, but the results of these studies were inconsistent. Therefore, we performed this meta-analysis to better evaluate the relationship between TNF-α polymorphisms and the risk of asthma. METHODS: Eligible studies were searched in PubMed, Medline, Embase and CNKI. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess correlations between TNF-α polymorphisms and asthma. RESULTS: A total of 50 studies were included for analyses. Significant associations with the risk of asthma were detected for TNF-α - 238 G/A, -308 G/A and - 857C/T polymorphisms in overall analyses. Further subgroup analyses according to ethnicity of participants revealed that TNF-α - 238 G/A polymorphism was significantly correlated with the risk of asthma in Caucasians, TNF-α - 308 G/A polymorphism was significantly correlated with the risk of asthma in West Asians, TNF-α - 857C/T polymorphism was significantly correlated with the risk of asthma in Caucasians, TNF-α - 863C/A polymorphism was significantly correlated with the risk of asthma in East Asians, and TNF-α - 1031 T/C polymorphism was significantly correlated with the risk of asthma in Caucasians and East Asians. CONCLUSIONS: Our findings indicated that TNF-α - 238 G/A, -308 G/A, -857C/T, -863C/A and - 1031 T/C polymorphisms may serve as potential biological markers for asthma in certain ethnicities.