In contrast to findings of previous research, low levels of von Willebrand Factor (VWF) and blood group O were not associated with a first-ever intracerebral hemorrhage (ICH), according to a study published in Thrombosis Research.

The researchers compared 176 cases of ICH with 349 age- and sex-matched controls. The mean patient age was 57 years, and 50% were women. The median time from baseline blood sampling to the first ICH was 5.6 years, according to the study reported by Kristina Johansson of Umeå (Sweden) University and her colleagues.

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The level of VWF differed significantly among blood groups: In individuals with blood group O, the mean VWF level was 1.29 kIU/L; for blood group A, it was 1.52 kIU/L; for blood group AB, 1.59 kIU/L; and in blood group B, 1.76 kIU/L. However, there was no difference in VWF concentration between cases and controls.

The researchers found no association between blood group O and the risk of ICH, a finding previously seen in other studies. They did, however, find that, in the limited number of patients with blood group B there was an association with a lower risk of ICH, compared with blood group A (odds ratio, 0.47; 95% confidence interval, 0.23-0.95).

“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,” the researchers concluded.

The study was funded by public institutions in Sweden. The authors declared that they had no conflicts.

SOURCE: Johansson K et al. Thromb Res. 2020 Jul 5;195:77-80.