title: Association between interleukin-6 -174G/C polymorphism and the risk of Alzheimer's disease: a meta-analysis.
abstract: BACKGROUND
  The -174G/C polymorphism in interleukin 6 (IL-6) gene has been extensively investigated for association to Alzheimer's disease (AD); however, results of different studies have been inconsistent. The objective of this study is to assess the relationship of IL-6 -174G/C polymorphism and Alzheimer's disease (AD) risk by using meta-analysis.
  
  
  METHODS
  All eligible case-control studies were searched in PubMed and EMBASE. Odds ratios (ORs) with the 95% confidence intervals (CIs) were used to assess the association.
  
  
  RESULTS
  A total of 5316 cases and 10 757 controls in 21 case-control studies were included. Obvious heterogeneity among studies was detected, and no significant association was observed between the IL-6 -174G/C polymorphism and AD risk. After exclusion of three studies, the heterogeneity disappeared and significant association was observed between the polymorphism and AD risk in Asians (CC vs. CG+GG: OR = 0.5; 95%CI, 0.33-0.75) but not in Caucasians.
  
  
  CONCLUSIONS
  This meta-analysis suggested that the -174G/C polymorphism of IL-6 gene would be a protective risk factor for AD in Asians. To further evaluate gene-to-gene and gene-to-environmental interactions between polymorphisms of IL-10 gene and AD risk, more studies with large groups of patients are required.
authors.affiliation: Department of Neurology, The Affiliated Wuxi Second Hospital, Nanjing Medical University, Wuxi, Jiangsu, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Hua
authors.forename: Xuedan
authors.initials: X
authors.lastname: Guo
authors.forename: Qing
authors.initials: Q
authors.lastname: Huang
authors.forename: Yuenan
authors.initials: Y
authors.lastname: Kong
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Lu
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics*; D044466:Asian People; D016022:Case-Control Studies; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*
chemical_list: D015850:Interleukin-6