Association between Single Nucleotide Polymorphisms in Interleukin-6 Gene and Periodontal Disease: A Systematic Review and Meta-analysis

Introduction: There has been much discussion recently about the influence of single nucleotide polymorphisms in interleukin-6 (IL-6) gene on periodontal disease in young healthy patients. The aim of the present work is to review the results of each case-control study which fulfills the inclusion criteria, and to perform a meta-analysis to make clear the association between single nucleotide polymorphisms (SNPs) in IL-6 gene and periodontal disease. Materials and methods: The search process was performed in the main databases in order to find the case-control studies published until August 2014 that matched inclusion criteria. Data were collected and odds ratio (OR) was calculated. Overall statistics was obtained with STATA. Results: Fifteen studies met the inclusion criteria. There was a lack of data for a proper comprehensive analysis for IL-6 (-373) An/Tm polymorphism and IL-6 (-597) G/A polymorphism. Meta-analysis showed no association between IL-6 (174) GG polymorphism and periodontitis. Similar results were obtained between the IL-6 (-572) SNPs genotype and periodontitis in all patients. A positive association was found when homozygote genotypes were investigated in within studies analysis and in Asian population. Discussion: Modest evidence of association has been found between interleukin-6 gene polymorphisms and periodontal disease.