title: Lack of evidence for association between factor XIII-A Val34Leu polymorphism and ischemic stroke: a meta-analysis of 8,800 subjects.
abstract: BACKGROUND
  Epidemiological studies have evaluated the association between factor XIII-A (FXIII-A) Val34Leu polymorphism and risk of ischemic stroke, but the results remain inconclusive. This meta-analysis was therefore designed to clarify these controversies.
  
  
  METHODS
  Systematic searches of electronic databases Embase, PubMed and Web of Science, as well as hand searching of the references of identified articles and the meeting abstracts were performed. Study selection, data abstraction and study quality evaluation (using the Newcastle-Ottawa Scale, NOS) were independently conducted in duplicate. Statistical analyses were performed using software Review Manager (Version 5.1.2) and Stata (Version 11.0). The pooled odds ratios (ORs) with 95% confidence intervals (95%CIs) were performed. Fixed or random effects model was separately used depending on the heterogeneity between studies. Publication bias was tested by funnel plot, Egger's regression test and Begg's test. Sensitivity analysis was conducted by limiting the meta-analysis to the high quality studies (NOS score≥8).
  
  
  RESULTS
  A total of 16 studies including 3,807 cases and 4,993 controls were combined showing no evidence of association between FXIII-A Val34Leu polymorphism and ischemic stroke (for Val/Leu vs. Val/Val : OR=0.95, 95%CI=0.77-1.16; for Leu/Leu vs. Val/Val: OR=0.90, 95%CI=0.73-1.11; for dominant model: OR=0.97, 95%CI=0.81-1.17; for recessive model: OR=0.95, 95%CI=0.77-1.17). In the subgroup analyses by study design, ethnicity and specific subtypes (small-vessel occlusive ischemic stroke and large-artery atherosclerotic ischemic stroke ), there was lack of evidence for the association.
  
  
  CONCLUSIONS
  This meta-analysis indicates that there is no evidence for association between factor XIII-A Val34Leu polymorphism and ischemic stroke.
authors.affiliation: Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing 400042, PR China.
authors.forename: Binghu
authors.initials: B
authors.lastname: Li
authors.forename: Lili
authors.initials: L
authors.lastname: Zhang
authors.forename: Yanwei
authors.initials: Y
authors.lastname: Yin
authors.forename: Yan
authors.initials: Y
authors.lastname: Pi
authors.forename: Qingwu
authors.initials: Q
authors.lastname: Yang
authors.forename: Changyue
authors.initials: C
authors.lastname: Gao
authors.forename: Chuanqin
authors.initials: C
authors.lastname: Fang
authors.forename: Jingzhou
authors.initials: J
authors.lastname: Wang
authors.forename: Jingcheng
authors.initials: J
authors.lastname: Li
mesh_terms: D016022:Case-Control Studies; D005006:Ethnicity / Q000235:genetics; D005176:Factor XIII / Q000235:genetics*; D006801:Humans; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D020521:Stroke / Q000208:ethnology / Q000235:genetics*
chemical_list: D005176:Factor XIII