title: Quantitative assessment of the associations between interleukin-8 polymorphisms and periodontitis susceptibility.
abstract: BACKGROUND
  This review assesses the associations of interleukin-8 gene (IL-8) -251A/T (rs4073) and -845T/C (rs2227532) polymorphisms with susceptibility to periodontitis.
  
  
  METHODS
  Several electronic databases were searched for eligible articles. Twelve studies involving 2,233 cases and 2,655 controls were retrieved and analyzed. Odds ratios (ORs) along with 95% confidence intervals (CIs) were calculated to assess the strength of relationship between the IL-8 polymorphisms and periodontitis risk.
  
  
  RESULTS
  No significant association was found for IL-8 -251A/T polymorphism with periodontitis in the overall analysis and stratification by periodontitis type and smoking status. Subgroup analysis by ethnicity revealed that -251A/T T allele and TT genotype were associated with decreased risk of periodontitis in a Brazilian mixed population (T allele versus A allele: OR 0.80, 95% CI 0.68 to 0.94, Pheterogeneity = 0.30; TT versus AA: OR 0.65, 95% CI 0.46 to 0.93, Pheterogeneity = 0.39; TT versus
  OR 0.58, 95% CI 0.35 to 0.98, Pheterogeneity = 0.01). In addition, -251A/T T allele was associated with increased periodontitis risk in Asians. Pooled estimates showed that the -845T/C polymorphism was associated with periodontitis susceptibility in overall analysis and the chronic periodontitis subgroup. In addition, marginal associations were observed between -845T/C polymorphism and periodontitis in a Brazilian mixed population. Moreover, this association was also confirmed to be significant in Brazilian non-smokers.
  
  
  CONCLUSIONS
  This meta-analysis indicated that both IL-8 -251A/T and -845T/C polymorphisms may be involved in the development of periodontitis in a Brazilian mixed population, whereas the -251A/T allele T appeared to be a risk factor for periodontitis in Asians.
authors.affiliation: Department of Stomatology, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Chen
authors.forename: Jinping
authors.initials: J
authors.lastname: Huang
authors.forename: Liangjun
authors.initials: L
authors.lastname: Zhong
authors.forename: Cheng
authors.initials: C
authors.lastname: Ding
mesh_terms: D000225:Adenine; D044466:Asian People / Q000235:genetics; D001938:Brazil / Q000208:ethnology; D003596:Cytosine; D005006:Ethnicity / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics*; D010518:Periodontitis / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D013941:Thymine
chemical_list: C508606:CXCL8 protein, human; D016209:Interleukin-8; D003596:Cytosine; D000225:Adenine; D013941:Thymine
keywords: Case-control study; disease susceptibility; interleukin-8; meta-analysis; periodontitis; polymorphism, genetic