title: Plasminogen activator inhibitor-1 4G/5G polymorphism and risk of stroke: replicated findings in two nested case-control studies based on independent cohorts.
abstract: OBJECTIVE
  Impaired fibrinolytic function secondary to elevated plasminogen activator inhibitor-1 (PAI-1) levels has been implicated in ischemic stroke. PAI-1 levels are determined by genetic factors and environmental factors, triglyceride levels in particular. The aim of this study was to investigate the common functional 4/5 guanosine (4G/5G) polymorphism in the promoter region of the PAI-1 gene and the risk of stroke.
  
  
  METHODS
  A nested case-control study design was applied, using baseline data for 2 independent cohorts obtained at population-based surveys in northern Sweden. In study A, there were 113, and in study B, there were 275 individuals without major concomitant disease at baseline who later experienced a first-ever stroke. Blood samples obtained at baseline were analyzed for potential risk factors, including the 4G/5G polymorphism of the PAI-1 gene.
  
  
  RESULTS
  The 4G allele of the PAI-1 polymorphism was associated with an increased risk of future ischemic stroke in both studies (odds ratio [OR] of 4G homozygosity, 1.87; 95% CI, 1.12 to 3.15 in study A; OR of 4G homozygosity, 1.56; 95% CI, 1.12 to 2.16 in study B). Individuals with the combination of hypertriglyceridemia and 4G homozygosity were at the greatest risk of developing stroke. Multiple logistic regression analysis identified 4G homozygosity, systolic blood pressure, and diabetes as independent predictors of ischemic stroke.
  
  
  CONCLUSIONS
  Identical findings in 2 independent studies strongly suggest a true and clinically important association between PAI-1 4G/5G genotype and risk of future ischemic stroke. The observed modification of the genotype effect by triglycerides may be interpreted as a gene-environment interaction.
authors: Department of Public Health and Clinical Medicine, Umeå University Hospital, Sweden. pg.wiklund@medicin.umu.se
authors: Per-Gunnar
authors: PG
authors: Wiklund
authors: Lennart
authors: L
authors: Nilsson
authors: Sofie Nilsson
authors: SN
authors: Ardnor
authors: Per
authors: P
authors: Eriksson
authors: Lars
authors: L
authors: Johansson
authors: Birgitta
authors: B
authors: Stegmayr
authors: Anders
authors: A
authors: Hamsten
authors: Dan
authors: D
authors: Holmberg
authors: Kjell
authors: K
authors: Asplund
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D001794:Blood Pressure; D016022:Case-Control Studies; D015331:Cohort Studies; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007511:Ischemia; D008875:Middle Aged; D016017:Odds Ratio; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics* / Q000502:physiology; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D012044:Regression Analysis; D012306:Risk; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis / Q000235:genetics*; D013548:Sweden; D013997:Time Factors; D014158:Transcription, Genetic; D014280:Triglycerides / Q000378:metabolism
chemical_list: D017395:Plasminogen Activator Inhibitor 1; D014280:Triglycerides