title: Distribution of ABO blood groups in the patients with intracranial aneurysm and association of different risk factors with particular blood type.
abstract: BACKGROUND
  The association between ABO blood groups and intracranial aneurysms is not well-known. Many co-morbid factors are associated with intracranial aneurysms. Our objective was to assess the prevalence of different blood group in patients with intracranial aneurysm and to look for associations between risk factors and these groups.
  
  
  METHODS
  This retrospective study includes 1,491 cases who underwent surgical operations for intracranial aneurysms from 1993-2014. We have evaluated the information related to clinical history, ABO blood groups and associated risk factors in the patients both ruptured and unruptured intracranial aneurysms by chart review of the cases.
  
  
  RESULTS
  In our study, out of 1,491 cases, the most common ABO blood groups were group O (668 cases, 44.80%) and Group A (603 cases, 40.44%), and Rh(+) in 1,319 (88.4%) and Rh(-) in 147 (11.6%). Blood Group A (43% vs. 36%) and Group B (16.2% vs. 8.6%) were significantly higher in Caucasian and African Americans respectively. However, in general population, there was no significant difference in blood groups between Caucasians and African Americans. Rh(-) factor was significantly higher in Caucasians compared to African Americans. Incidence of smoking was significantly higher in aneurysm patients with O group compared to others. In addition, incidence of hypercholesterolemia was significantly higher in aneurysm patients with A group compared to others.
  
  
  CONCLUSIONS
  The racial disparity in the distribution of blood groups, and risk factor association with blood groups in the development of intracranial aneurysm needs to be considered. The findings from our study may be useful in identifying patients at increased risk. Further study may be required to establish the risks from multiple centers studies around the world.
authors.affiliation: Department of Neurosurgery, LSU Health-Shreveport, 1501 Kings Highway, Shreveport, LA 71130-3932, USA.
authors.forename: Shyamal Chandra
authors.initials: SC
authors.lastname: Bir
authors.affiliation: Department of Neurosurgery, LSU Health-Shreveport, 1501 Kings Highway, Shreveport, LA 71130-3932, USA.
authors.forename: Papireddy
authors.initials: P
authors.lastname: Bollam
authors.affiliation: Department of Neurosurgery, LSU Health-Shreveport, 1501 Kings Highway, Shreveport, LA 71130-3932, USA.
authors.forename: Anil
authors.initials: A
authors.lastname: Nanda
keywords: ABO blood type; intracranial aneurysm; risk factors