ABO blood group and Rh factor distributions in patients with epilepsy

We investigated the ABO blood group and Rh factor distributions in patients with epilepsy (PWE) in comparison with a comparator population.We recruited patients who were admitted to the epilepsy ward at Namazi hospital in Shiraz, Iran, in 2021. We classified epilepsies into two categories: focal vs. generalized. We also used the anonymous data from Fars Blood Transfusion Organization from 15th June to 30th June, 2021, as the comparator population (to estimate the frequencies of various blood types in the cohort from which PWE were recruited).Overall, 390 PWE were included [131 (33.6%) with generalized and 259 (66.4%) with focal epilepsy]. We also included 7672 blood donors [from Fars Blood Transfusion Organization data]. The O phenotype had the highest frequencies in both PWE and the comparator population, followed by A, B, and AB blood groups. Similar patterns were observed in patients with focal and generalized epilepsy. With regard to Rh blood group, the Rh-positive phenotype was more prevalent in all groups. The differences between the groups were not significant in any of the comparisons.While we did not observe any significant associations between blood group and epilepsy in the current study, previous studies have demonstrated compelling evidence that risks of some neuropsychiatric disorders are related to the chemistry of blood, including blood group classification. The issue of the association between epilepsy and blood group should be investigated in large and well-designed studies in the future.