Association between Tumor Necrosis Factor-α 308G/A Gene Polymorphism and Silicosis Susceptibility: A Meta-Analysis

Background: Tumor necrosis factor-alpha (TNF-alpha) 308 G/A gene polymorphism has been reported to be associated with susceptibility to silicosis. However, the relevant study results are still inconsistent. Objective and Methods: A meta-analysis was performed in order to drive a more precise estimation of the relationship between TNF-alpha-308 G/A gene polymorphism and susceptibility to silicosis. Electronic databases were searched and nine separate studies were included. The pooled odds ratios (ORs) and the corresponding 95% confidence internal (CI) were calculated by a fixed effect model. Results: A total of 1267 cases and 1214 controls were included. In the overall analysis, significantly increased silicosis risk was found (for GA+AA vs. GG OR=1.45, 95%CI: 1.20-1.760, P=1.58E4; for GA vs. GG: OR=1.53, 95%CI=1.25-1.86, P=3.11E5; for A allele vs. G allele: OR=1.27, 95%CI=1.08-1.50, P=0.004). In the subgroup analysis, significantly increased silicosis risk was also found among Asians (for GA+AA vs. GG: OR=1.63, 95%CI=1.27-2.08, P=1.01E4), for GA vs. GG: OR=1.71, 95%CI=1.33-2.20, P=3.44E5), for A allele vs. G allele: OR=1.45, 95%CI=1.17-1.80, P=0.001). However, no significantly increased risk was found among non-Asians for all genetic models. Conclusions: TNF-alpha-308 G/A polymorphism might lead to an increased risk of silicosis susceptibility, especially for Asians. However, further studies with large sample sizes should be conducted to confirm the association.