title: Associations between tumor necrosis factor-α polymorphisms and risk of psoriasis: a meta-analysis.
abstract: BACKGROUND
  Tumor necrosis factor-α (TNF-α) may play an important role in the recalcitrant inflammatory and hyperproliferative dermatosis of psoriasis, and there may be a relationship between TNF-α polymorphisms and psoriasis risk.
  
  
  METHODS
  We performed a meta-analysis to evaluate the associations between TNF-α polymorphisms and psoriasis. Electronic searches of Pubmed, Embase, and Web of Science were performed for all publications on the associations between TNF-α polymorphisms and psoriasis through September 26, 2012. The pooled odds ratios (ORs) with their 95% confidence interval (95%CIs) were calculated to assess the associations.
  
  
  RESULTS
  Sixteen case-control studies with a total of 2,253 psoriasis cases and 1,947 controls on TNF-α 308 G/A polymorphism and fourteen studies on TNF-α 238 G/A polymorphism with 2,104 cases and 1,838 controls were finally included into the meta-analysis. Overall, TNF-α 308 G/A polymorphism was significantly associated with decreased risk of psoriasis under three genetic comparison models (for A versus G: fixed-effects OR 0.71, 95%CI 0.62-0.82, P < 0.001; for AG versus GG: fixed-effects OR 0.67, 95%CI 0.57-0.78, P < 0.001; for AA/AG versus GG: fixed-effects OR 0.67, 95%CI 0.58-0.78, P < 0.001). In addition, TNF-α 238 G/A polymorphism was associated with increased risk of psoriasis under three genetic models (for A versus G: fixed-effects OR 2.46, 95%CI 2.04-2.96, P < 0.001; for AG versus GG: fixed-effects OR 2.69, 95%CI 2.20-3.28, P < 0.001; for AA/AG versus GG: fixed-effects OR 2.68, 95%CI 2.20-3.26, P < 0.001). Subgroup analysis by ethnicity identified a significant association between TNF-α 308 G/A polymorphism and decreased risk of psoriasis in both Caucasians and Asians and a significant association between TNF-α 238 G/A polymorphism and increased risk of psoriasis in Caucasians.
  
  
  CONCLUSIONS
  The meta-analysis suggests that TNF-α 308 G/A polymorphism is associated with decreased risk of psoriasis, while TNF-α 238 G/A is associated with increased risk of psoriasis.
authors: Department of Dermatology, Qilu Hospital, Shandong University, Jinan, China.
authors: Le
authors: L
authors: Zhuang
authors: Weiyuan
authors: W
authors: Ma
authors: Daxing
authors: D
authors: Cai
authors: Hua
authors: H
authors: Zhong
authors: Qing
authors: Q
authors: Sun
mesh_terms: D016022:Case-Control Studies; D016206:Databases, Bibliographic; D020022:Genetic Predisposition to Disease; D006801:Humans; D008957:Models, Genetic; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D011565:Psoriasis / Q000175:diagnosis / Q000235:genetics*; D012306:Risk; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D014409:Tumor Necrosis Factor-alpha