title: Association between interleukin-4 gene -590 c/t, -33 c/t, and 70-base-pair polymorphisms and periodontitis susceptibility: a meta-analysis.
abstract: BACKGROUND
  Several studies have investigated the association between interleukin (IL)-4 gene -590 C/T, -33 C/T, or 70-base pair (70-bp) polymorphisms and periodontitis susceptibility but with conflicting results. Hence, a meta-analysis was conducted to explore whether these polymorphisms are associated with periodontitis susceptibility.
  
  
  METHODS
  A comprehensive literature search was conducted of PubMed, Embase, Scopus, ScienceDirect, and Web of Science up to April 5, 2014. After the eligible studies were identified, data were extracted and quality-assessed before performing the meta-analysis.
  
  
  RESULTS
  The meta-analysis included 23 eligible case-control studies from 11 articles involving 12 studies of the -590 C/T polymorphism (1,220 cases and 2,039 controls), five of the -33 C/T polymorphism (715 cases and 967 controls), and four of the 70-bp polymorphism (426 cases and 506 controls). The meta-analysis showed that none of these IL-4 gene polymorphisms were significantly associated with periodontitis susceptibility in all study participants. However, subgroup analysis showed that the IL-4 -590 T allele (odds ratio [OR] = 1.2, 95% confidence interval [CI] = 1.02 to 1.42, P = 0.03) and TT genotype (OR = 1.68, 95% CI = 1.05 to 2.67, P = 0.03) were associated with periodontitis in whites.
  
  
  CONCLUSIONS
  Based on current evidence, the IL-4 -33 C/T and 70-bp polymorphisms were not associated with an increased risk of periodontitis. However, the IL-4 -590 T allele and TT genotype were associated with increased risk of periodontitis in whites.
authors.affiliation: Department of Stomatology, Taihe Hospital, Hubei University of Medicine, Shiyan, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Yan
authors.forename: Hong
authors.initials: H
authors.lastname: Weng
authors.forename: Zheng-Hai
authors.initials: ZH
authors.lastname: Shen
authors.forename: Lan
authors.initials: L
authors.lastname: Wu
authors.forename: Xian-Tao
authors.initials: XT
authors.lastname: Zeng
mesh_terms: D000483:Alleles; D020029:Base Pairing / Q000235:genetics*; D003596:Cytosine; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics; D005838:Genotype; D006801:Humans; D015847:Interleukin-4 / Q000235:genetics*; D010518:Periodontitis / Q000235:genetics / Q000276:immunology*; D011110:Polymorphism, Genetic / Q000235:genetics*; D013941:Thymine
chemical_list: C508598:IL4 protein, human; D015847:Interleukin-4; D003596:Cytosine; D013941:Thymine
keywords: Aggressive periodontitis; chronic periodontitis; interleukin-4; meta-analysis; periodontal diseases; polymorphism, genetic