In contrast to controls, younger age was associated with greater hippocampal atrophy rate in AD patients, corresponding to a reduction in atrophy rate of 0.03 mL/y (0.05, 0.001) for a 10-year increase in age after adjusting for WMH and APOE e4 and subtracting the age–atrophy effect in controls. This evidence concerns the gene APOE and hippocampal atrophy.