title: Polymorphisms of interleukin-1 and interleukin-6 genes on the risk of ischemic stroke in a meta-analysis.
abstract: Many epidemiological studies have investigated the associations between polymorphisms of interleukin-1 (IL1) and interleukin-6 (IL6) genes and risk of ischemic stroke (IS), but no conclusions are available because of conflicting results. The aim of this study was to assess the relationships by meta-analysis. The databases of Pubmed, Embase and Wangfang, updated to August 1st, 2011, were retrieved. Odds ratio (OR) and corresponding 95% confidence interval (95% CI) as effect size were calculated by a fixed- or random-effect model. In total, three case-control studies for IL1α-889C/T, eight studies for IL1β-511C/T, eight studies for IL1-Ra and seven studies for IL6-147G/C were included in this meta-analysis. Combined analysis indicated that IL1β-511C/T polymorphism was not overall associated with risk of IS [OR (95% CI)=1.22 (0.85-1.87) for TT vs. CC]. However, when subgroup analyses for countries were conducted, the results indicated that T allele was associated with increased risk of IS for Polish and associated with a trend of increased risk of IS for Chinese although it did not reach statistical significance [TT vs. CC: OR (95% CI)=1.97 (1.22-3.17) for Polish and 1.40 (0.99-1.99) for Chinese]. In addition, overall and subgroup analyses indicated that IL1α-889C/T, IL1-Ra and IL6-147G/C polymorphisms were also not associated with risk of IS [OR (95% CI)=1.21 (0.86-1.70) for TT vs. CC of IL1α-889C/T, 1.22 (0.85-1.75) for RN2/RN2 vs. RN1/RN1 for IL1-Ra and 1.09 (0.84-1.40) for G carriers vs. C carriers for IL6-147G/C]. This study inferred that IL1β-511C/T polymorphism might be moderately associated with increased risk of IS, but no sufficient evidence was available to support any associations between IL1-Ra and IL6-147G/C polymorphisms and IS. We could not draw a conclusion between IL1α-889C/T polymorphism and risk of IS based on the limited data, and further large sample-sized studies were required.
authors.affiliation: Department of Neurology of Ren Min Hospital, Hubei University of Medicine, PR China.
authors.forename: Fei
authors.initials: F
authors.lastname: Ye
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Jin
authors.forename: Guang-Hui
authors.initials: GH
authors.lastname: Chen
authors.forename: Xiao-Ling
authors.initials: XL
authors.lastname: Den
authors.forename: Yong-Qiang
authors.initials: YQ
authors.lastname: Zheng
authors.forename: Cheng-Yan
authors.initials: CY
authors.lastname: Li
mesh_terms: D000465:Algorithms; D044466:Asian People / Q000235:genetics; D002545:Brain Ischemia / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics*; D053582:Interleukin-1alpha / Q000235:genetics; D053583:Interleukin-1beta / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics*; D008297:Male; D011110:Polymorphism, Genetic / Q000502:physiology; D053573:Receptors, Interleukin-1 Type I / Q000235:genetics / Q000378:metabolism; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics*
chemical_list: C508584:IL1A protein, human; C508585:IL1B protein, human; C508590:IL1R1 protein, human; C508600:IL6 protein, human; D007375:Interleukin-1; D053582:Interleukin-1alpha; D053583:Interleukin-1beta; D015850:Interleukin-6; D053573:Receptors, Interleukin-1 Type I