title: Association between interleukin-6 (G174C and C572G) promoter gene polymorphisms and risk of ischemic stroke in North Indian population: a case-control study.
abstract: BACKGROUND
  Polymorphisms of G174C and C572G in the interleukin-6 (IL-6) promoter gene can affect both transcription and secretion of IL-6 and may be involved in inflammation related to and pathogenesis of ischemic stroke (IS). Whether these IL-6 gene polymorphisms are risk factors for IS or not, remains controversial.
  
  
  OBJECTIVE
  The aim of this study was to determine the association between IL-6 G174C and C572G gene polymorphisms and susceptibility to ischemic stroke in North Indian Population.
  
  
  METHODS
  Two hundred and fifty IS patients and 250 age- and sex-matched controls were studied. Genotyping was performed using SNaPshot method. Stroke was classified using Trial of Org 10172 in acute stroke treatment classification. Conditional logistic regression analysis was used to calculate the strength of association between IL-6 (G174C and C572G) polymorphisms and risk of IS.
  
  
  RESULTS
  Hypertension, diabetes, dyslipidemia, alcohol, smoking, family history of stroke, sedentary life style and low socioeconomic status were found to be associated with the risk of IS. Conditional logistic regression analysis showed a significant association of IL-6 G174C with the risk of IS under dominant model (OR, 1.61; 95%CI, 1.0-2.4; P value 0.02) and allelic model (OR, 1.5; 95%CI, 1.0-2.1; P value 0.02). For IL-6 C572G, multivariate adjusted analysis showed a significant association with the risk of IS under dominant model for overall IS (OR, 1.81; 95%CI, 1.04-3.15; P value 0.03) and small vessel disease subtype of IS (OR, 2.8; 95%CI, 1.3-6.0; P value 0.006).
  
  
  CONCLUSIONS
  Our results suggest that IL-6 (G174C) polymorphism is significantly associated with the risk of IS in North Indian population. However, IL-6 (C572G) polymorphism is found significantly associated with the risk of IS after adjusting the demographic and risk factors variables. Prospective studies with large sample size are required for independent validation. Our findings could be helpful in identifying individuals at increased risk for developing IS.
authors.affiliation: a Department of Neurology , All India Institute of Medical Sciences , New Delhi , India.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kumar
authors.affiliation: a Department of Neurology , All India Institute of Medical Sciences , New Delhi , India.
authors.forename: Amit
authors.initials: A
authors.lastname: Kumar
authors.affiliation: a Department of Neurology , All India Institute of Medical Sciences , New Delhi , India.
authors.forename: Ram
authors.initials: R
authors.lastname: Sagar
authors.affiliation: a Department of Neurology , All India Institute of Medical Sciences , New Delhi , India.
authors.forename: Shubham
authors.initials: S
authors.lastname: Misra
authors.affiliation: b Institutes of Genomics and Integrative Biology , New Delhi , India.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Faruq
authors.affiliation: a Department of Neurology , All India Institute of Medical Sciences , New Delhi , India.
authors.forename: Varun
authors.initials: V
authors.lastname: Suroliya
authors.affiliation: c Department of Neurobiochemistry , All India Institute of Medical Sciences , New Delhi , India.
authors.forename: Subiah
authors.initials: S
authors.lastname: Vivekanandhan
authors.affiliation: a Department of Neurology , All India Institute of Medical Sciences , New Delhi , India.
authors.forename: Achal
authors.initials: A
authors.lastname: Kumar Srivastava
authors.affiliation: a Department of Neurology , All India Institute of Medical Sciences , New Delhi , India.
authors.forename: Kameshwar
authors.initials: K
authors.lastname: Prasad
mesh_terms: D000328:Adult; D002545:Brain Ischemia / Q000150:complications; D016022:Case-Control Studies; D005260:Female; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D007194:India / Q000453:epidemiology; D015850:Interleukin-6 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D020521:Stroke / Q000000981:diagnostic imaging / Q000209:etiology* / Q000235:genetics*
chemical_list: D015850:Interleukin-6
keywords: Ischemic stroke; cytokine; inflammatory gene; interleukin-6; promoter; single nucleotide polymorphisms