APOE and Alzheimer disease: The AD cohort was significantly older by 9.8 years (AD group 79.6 ± 3.1 years, HC group 69.8 ± 3.2 years, p = 0.0001) and the AD population was significantly enriched in the APOE ε4 allele (40%, AD; 13%, HC; p = 0.0001) as anticipated [48].