title: Relationship between Interleukin-6 (-174G/C and -572C/G) Promoter Gene Polymorphisms and Risk of Intracerebral Hemorrhage: A Meta-Analysis.
abstract: BACKGROUND
  Polymorphisms of -174G/C and -572C/G in the Interleukin-6 (IL-6) promoter gene can affect both transcription and secretion of IL-6 and may be involved in the inflammatory mechanisms in early and delayed phases after intracerebral hemorrhage (ICH). The role of these polymorphisms remains unclear for the pathogenesis of ICH.
  
  
  METHODS
  PubMed, EMBASE, MEDLINE and Google Scholar searches were conducted from January 1, 1950 to February 29, 2016 and were supplemented with relevant articles identified in the references. The following search terms were used: ('interleukin-6' or 'IL-6') and ('genetic polymorphism' or 'single nucleotide polymorphisms' or 'SNP') and ('intracerebral hemorrhage' or 'ICH') and ('hemorrhagic stroke' or 'HS'). Fixed or random effects models were used to estimate the pooled odds ratios and 95% confidence intervals. Begg's funnel plot was used to assess the potential for publication bias.
  
  
  RESULTS
  In our meta-analysis, three case-control studies involving 446 ICH cases and 2,322 controls were included. No significant association was observed for the IL-6 (-174G/C and -572C/G) gene polymorphisms with the risk of ICH under dominant, recessive and allelic models.
  
  
  CONCLUSIONS
  Our meta-analysis suggests that IL-6 gene polymorphisms are not associated with the risk of ICH. However, caution must be taken while considering the results of our meta-analysis due to the presence of small sample size. Our results cannot be extrapolated to represent the effect of entire IL-6 genetic polymorphism on stroke patients worldwide. Therefore, further well-designed studies with large sample size are warranted to validate our findings and provide a profound conclusion.
authors.affiliation: Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Shubham
authors.initials: S
authors.lastname: Misra
authors.affiliation: Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Arun
authors.initials: A
authors.lastname: Kumar Yadav
authors.affiliation: Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Mukesh
authors.initials: M
authors.lastname: Sriwastva
authors.affiliation: Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Kameshwar
authors.initials: K
authors.lastname: Prasad
keywords: Cytokine; Interleukin-6; Intracerebral hemorrhage; Single nucleotide polymorphisms