title: No evidence for an association between ABO blood group and overall ischemic stroke or any of the major etiologic subtypes.
abstract: BACKGROUND
  The ABO blood group system is encoded by one gene, ABO. Previous studies have reported an association between blood group non-O (i.e. phenotype A, B or AB) and myocardial infarction. Studies on stroke and ABO are, however, more scarce. Therefore, we aimed to investigate whether ABO phenotype or genotype is associated with ischemic stroke and/or etiologic subtypes of ischemic stroke.
  
  
  METHODS
  The study was performed in the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS), which comprises 600 patients with ischemic stroke before the age of 70 years, and 600 matched controls. Patients were classified according to the TOAST criteria.
  
  
  RESULTS
  There was no significant association between ABO phenotype (blood group O vs. non-O) and overall ischemic stroke (multivariable odds ratio of 0.9, 95% confidence interval 0.7-1.2). This was also true for blood group O vs. A and O vs. B. Furthermore, no association between ABO genotypes and ischemic stroke was detected. The ischemic stroke subtype analysis was confined to large-vessel disease, small-vessel disease, cardioembolic stroke and cryptogenic stroke. In this analysis, there was no significant association between any ischemic stroke subtype and ABO phenotype or genotype.
  
  
  CONCLUSIONS
  The findings in this study suggest that ABO phenotype or genotype does not have a major impact in the pathophysiology of ischemic stroke or any of the ischemic stroke subtypes.
authors.affiliation: Institute of Neuroscience and Physiology, the Sahlgrenska Academy at University of Gothenburg, Sweden. ellen.hanson@neuro.gu.se
authors.forename: Ellen
authors.initials: E
authors.lastname: Hanson
authors.forename: Sara
authors.initials: S
authors.lastname: Karlsson
authors.forename: Katarina
authors.initials: K
authors.lastname: Jood
authors.forename: Staffan
authors.initials: S
authors.lastname: Nilsson
authors.forename: Christian
authors.initials: C
authors.lastname: Blomstrand
authors.forename: Christina
authors.initials: C
authors.lastname: Jern
mesh_terms: D000017:ABO Blood-Group System / Q000097:blood / Q000235:genetics*; D002545:Brain Ischemia / Q000097:blood / Q000453:epidemiology* / Q000235:genetics*; D015897:Comorbidity; D019317:Evidence-Based Medicine; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology* / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D020521:Stroke / Q000097:blood / Q000453:epidemiology* / Q000235:genetics*; D013548:Sweden / Q000453:epidemiology
chemical_list: D000017:ABO Blood-Group System