Although APOE-ε4 status confers an elevated risk of AD development and has been associated with hippocampal atrophy in individuals with MCI and AD,35 there was not a significant relationship between APOE-ε4 status and HAR in our main analysis sample, nor did it account for the association between WMHVR and HAR. This evidence concerns the gene APOE and hippocampal atrophy.