Tumor necrosis factor gene polymorphisms are associated with silicosis: a systemic review and meta-analysis

Studies investigating association between tumor necrosis factor (TNF) gene polymorphisms and silicosis susceptibility report conflicting results. The aim of this meta-analysis was to assess association between TNF gene polymorphisms and silicosis susceptibility. A systematic literature search was conducted to find relevant studies. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the strength of association. Finally, a total of 12 articles, involving 1990 silicosis patients and 1898 healthy controls were included in the meta-analysis. Overall, meta-analysis revealed a significant association between the TNF -308A allele and silicosis (OR = 1.348, 95%CI = 1.156-1.570, P<0.001). A significant association of AA+AG genotype of the TNF -308 A/G polymorphism with susceptibility to silicosis was also found (OR = 1.466, 95%CI = 1.226-1.753, P<0.001). After stratification by ethnicity, significant associations were detected under the genetic models (A allele and AA+AG genotype) for TNF -308A/G polymorphisms in the Asian population (P<0.05). Similarly, meta-analysis of the TNF -238A/G polymorphism revealed the same pattern as that shown by meta-analysis of TNF -308A/G. The meta-analysis suggests that the TNF -308A/G and -238A/G polymorphisms are associated with susceptibility to silicosis, especially in Asians.