APOE and Alzheimer disease: When participants were not stratified by the APOE genotype, there was no significant difference in the HDL CEC index between the control, MCI, and AD participants by one-way ANOVA (1.10 ± 0.16, 1.06 ± 0.14, and 1.12 ± 0.14, F(2, 191) = 2.14, p = 0.120, Figure 1A).