title: Relationship between -889 C/T polymorphism in interleukin-1A gene and risk of chronic periodontitis: Evidence from a meta-analysis with new published findings.
abstract: BACKGROUND
  Periodontitis results from an inflammatory response caused by accumulative microorganisms in periodontal sites. Several factors are involved in pathogenesis of periodontitis, for example the -889 C/T polymorphism in interleukin-1A gene. This study aimed to evaluate the relationship between this polymorphism and risk of development of chronic periodontitis by a meta-analysis based in new published findings.
  
  
  METHODS
  Thereunto a review in literature was performed in the electronic biomedical and education databases (Cochrane Library, Google Scholar, MEDLINE and PubMed) to studies published before August 2, 2015, the abstracts were evaluated and the data extraction performed by two calibrated examiners. The calculations of the meta-analysis were obtained through statistical software Review Manager version 5.2 with calculation of Odds Ratio (OR), heterogeneity (I²) and Funnel plots with P < 0.05.
  
  
  RESULTS
  In overall, twenty-one case/control studies were selected with 2,174 patients with chronic periodontitis and 1, 756 controls. The meta-analysis showed T allele was associated with chronic periodontitis (OR = 1.22, 95% CI: 1.09, 1.36, P = 0.0004) with decreased value to heterogeneity (I² = 15%, P = 0.28). TT genotype was associated to patients with chronic periodontitis (OR = 1.40, 95% CI: 1.07, 1.83, P = 0.01). No publication bias was found in this meta-analysis by asymmetry in Funnel plots.
  
  
  CONCLUSIONS
  This meta-analysis with 2,174 patients with chronic periodontitis and 1, 756 controls evidenced the -889 C/T polymorphism is associated to risk of development of chronic periodontitis with no significant value to heterogeneity to allelic evaluation.
authors.affiliation: Universidade Federal do Piauí- UFPI, Campus Ministro Reis Veloso, Colegiado de Biomedicina, Av. São Sebastião, 2819, Reis Veloso, Parnaíba - PI - Brasil, 64204-035, vasconcelos@ufpi.edu.br.
authors.forename: F-R-P
authors.initials: FR
authors.lastname: da Silva
authors.forename: A-C-C
authors.initials: AC
authors.lastname: Guimarães-Vasconcelos
authors.forename: L-F
authors.initials: LF
authors.lastname: de-Carvalho-França
authors.forename: D
authors.initials: D
authors.lastname: di-Lenardo
authors.forename: L-S
authors.initials: LS
authors.lastname: Rodrigues
authors.forename: M-L-L
authors.initials: ML
authors.lastname: Barreto-do-Nascimento
authors.forename: D-F-P
authors.initials: DF
authors.lastname: Vasconcelos
mesh_terms: D055113:Chronic Periodontitis / Q000235:genetics*; D006801:Humans; D053582:Interleukin-1alpha / Q000235:genetics*; D011110:Polymorphism, Genetic; D012307:Risk Factors
chemical_list: C508584:IL1A protein, human; D053582:Interleukin-1alpha