Von Willebrand factor, ABO blood group, and risk of first-ever intracerebral hemorrhage: A prospective nested case-control study

Low levels of von Willebrand factor (VWF) were associated with intracerebral hemorrhage (ICH) in a previous study. Persons with blood group O have lower VWF levels than other ABO blood groups. This study aimed to investigate the association between VWF and the risk of ICH in adults, as well as the association between ABO blood group and risk of ICH.This population-based, nested case-control study was conducted using data and blood samples from health examinations between 1985 and 2007. All participants were followed, and cases with first-ever ICH were identified and validated. One or two controls were matched to each case.During a median follow-up time from blood sampling to ICH of 5.6 years, 176 cases with ICH were identified. The mean age at health examination was 57 years; 50% of participants were women. There was an association between hypertension and risk of ICH, but there was no association between VWF level and risk of ICH. There was no association between blood group O and risk of ICH.To our knowledge this is the largest prospective study investigating the association between VWF, ABO blood group and ICH. We found no association between VWF or blood group O and risk of future ICH.