APOE and Parkinson disease: When comparing participants diagnosed with dementia or PD during the 15-year follow-up (n = 58) with the rest of the sample, those who received a diagnosis were older at baseline, had fewer years of formal schooling, were more likely to be hypertensive, APOE ε4 carriers, and have lacunes, and showed lower performance in global cognition, OID, and semantic memory, larger WMH and lateral ventricular volumes, as well as smaller hippocampal, amygdalar, and total GM volumes (p < 0.05, Supplementary Table 9).