ApoE4 is associated with increased risk of intracerebral hemorrhage (ICH)298 and predicts unfavorable neurological outcome after TBI and stroke.283,299 ApoE4 also appears to have direct effects on the cerebrovascular system and may affect neurovascular functions independently of its known influence on amyloid beta (Aβ) pathology in AD.300,301. This evidence concerns the gene APOE and Alzheimer disease.