Supplementary Material for: A Meta-Analysis of the Relationship between Tumor Necrosis Factor-α Polymorphisms and Psoriasis

Background: Some previous studies already explored associations between tumor necrosis factor-α (TNF-α) polymorphisms and psoriasis, with conflicting findings. Here, we aimed to better analyze the relationship between TNF-α polymorphisms and psoriasis in a larger pooled population by performing a meta-analysis. Methods: We searched Pubmed, Embase, Web of Science and CNKI for related articles. We calculated OR and 95% CI to estimate whether there are genetic associations between TNF-α polymorphisms and psoriasis. Results: Twenty-nine studies were included for this meta-analysis. TNF-α-238 G/A (dominant comparison: OR 0.44, 95% CI 0.34–0.59; recessive comparison: OR 1.63, 95% CI 1.03–2.57; overdominant comparison: OR 2.21, 95% CI 1.71–2.85; allele comparison: OR 0.48, 95% CI 0.36–0.62) and -857 C/T (dominant comparison: OR 0.58, 95% CI 0.41–0.80; overdominant comparison: OR 1.58, 95% CI 1.12–2.23; allele comparison: OR 0.62, 95% CI 0. 0.47–0.82) polymorphisms were found to be significantly associated with psoriasis in the general population. Subgroup analyses indicated that the –238 G/A polymorphism was significantly associated with psoriasis in Caucasians and East Asians, the –308 G/A polymorphism was significantly associated with psoriasis in East Asians, and the –857 C/T polymorphism was significantly associated with psoriasis in Caucasians. Conclusions: TNF-α –238 G/A, –308 G/A and –857 C/T polymorphisms could be used to identity individuals with elevated susceptibility to psoriasis in certain populations.