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.
https://pubmed.ncbi.nlm.nih.gov/17537274/
Blood group O is known to be associated with a lower expression of von Willebrand factor which plays an important role in clotting. Blood group O is more common blood group in both groups of patients. It is significantly higher in patients with epistaxis compare with non epistaxis patients. It suggests that blood group O may be a risk factor in the development of epistaxis.
https://www.arquivosdeorl.org.br/additional/acervo_eng.asp?id=565
Our study indicates that in the Turkish population, the 0 blood type is over-represented in patients with idiopathic epistaxis versus the general population. We conclude that blood type 0 is a risk factor for idiopathic epistaxis in the Turkish population.
https://pubmed.ncbi.nlm.nih.gov/29553612/