APOE and hippocampal atrophy: Younger age was also associated with greater hippocampal atrophy rate in MCI, in which a reduction in atrophy rate of 0.04 mL/y (0.02–0.06) for a 10 year increase in age was seen after adjusting for WMH and APOE e4 and subtracting the age-atrophy effect in controls.