title: Interleukin-1β (3953/4) C→T polymorphism increases the risk of chronic periodontitis in Asians: evidence from a meta-analysis of 20 case-control studies.
abstract: BACKGROUND
  To investigate the association of the interleukin-1β (IL-1β) (3953/4) C→T polymorphism with chronic periodontitis (CP) in Asians.
  
  
  METHODS
  Systematic searches of electronic databases and hand searching of references were performed, including PubMed, Embase, the Cochrane Library, and the Chinese National Knowledge Infrastructure (CNKI). Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the associations. Publication bias was tested by Egger's test. Sensitivity analysis was conducted by limiting the meta-analysis studies conforming to Hardy-Weinberg equilibrium (HWE). Data analyses were carried out using RevMan 6.0.
  
  
  RESULTS
  A meta-analysis was performed on 20 published case-control studies, including 1,656 CP cases and 1,498 healthy controls. The pooled OR was 1.60 (95% CI = 1.02-2.52, p = 0.04) for the T allele carriers (TT + CT) compared with CC and 1.60 (95% CI = 1.06-2.42, p = 0.02) for T vs. C. Subgroup analysis by country revealed significant risks of CP among Indians carrying the T allele (TT vs. CC: OR = 3.88, 95% CI = 1.77-8.50, p = 0.0007).
  
  
  CONCLUSIONS
  The analysis showed that IL-1β (3953/4) C→T polymorphism probably increases the risk of CP in Asians, and the IL-1β+3954 TT genotype may be associated with a strongly increased risk of CP in Indians, but not in Chinese.
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, Jiangsu, China ; Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Ma
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, Jiangsu, China ; Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China.
authors.forename: Wei-Ming
authors.initials: WM
authors.lastname: Chu
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, Jiangsu, China ; Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, Jiangsu, China ; Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China.
authors.forename: Yu-Nong
authors.initials: YN
authors.lastname: Wu
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, Jiangsu, China.
authors.forename: Zi-Lu
authors.initials: ZL
authors.lastname: Wang
keywords: Asians; chronic periodontitis; interleukin-1; meta-analysis; polymorphism