title: Is there an association between blood group O and epistaxis?
abstract: BACKGROUND
  Blood group O is associated with lower expression of von Willebrand factor suggesting a relative bleeding tendency. A lower admission rate for epistaxis among Asians compared with Caucasians has also been noted, with one explanation being higher prevalence of blood group O among Caucasians. This study investigates whether blood group O is over-represented in patients admitted with epistaxis.
  
  
  METHODS
  A retrospective study was conducted, using computerised hospital in-patient and blood bank databases to identify Caucasians admitted with epistaxis between January 2000 and December 2005 inclusive. The control group consisted of 500 consecutive patients who had a primary total hip arthroplasty and 500 consecutive patients who gave birth within the delivery suite.
  
  
  RESULTS
  1261 Caucasians admitted with epistaxis were identified. Among epistaxis patients, 50.44 per cent were blood group O but among the control group this was 45.10 per cent (chi-square test p = 0.008).
  
  
  CONCLUSIONS
  Blood group O appears over-represented in Caucasian patients admitted with epistaxis, compared with the control population, raising the possibility that blood group O is a risk factor for epistaxis.
authors.affiliation: Department of Otorhinolaryngology, Leicester Royal Infirmary, Leicester, UK. vmreddy@doctors.net.uk
authors.forename: V M
authors.initials: VM
authors.lastname: Reddy
authors.forename: M
authors.initials: M
authors.lastname: Daniel
authors.forename: E
authors.initials: E
authors.lastname: Bright
authors.forename: S R
authors.initials: SR
authors.lastname: Broad
authors.forename: A A
authors.initials: AA
authors.lastname: Moir
mesh_terms: D000017:ABO Blood-Group System; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004198:Disease Susceptibility; D004739:England / Q000453:epidemiology; D004844:Epistaxis / Q000097:blood* / Q000208:ethnology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D044465:White People / Q000706:statistics & numerical data
chemical_list: D000017:ABO Blood-Group System