APOE and hippocampal atrophy: APOE ε4 carriers had higher whole brain atrophy rates (adjusted mean difference, 0.16% (95% CI, 0.02 to 0.30%)) and hippocampal atrophy rates (adjusted mean difference, 0.68% (95% CI, 0.28 to 1.07%)) compared with APOE ε4 noncarriers.