In the blood datasets, compared to controls, AD patients were significantly older (mean ± SD for AD: 77.0 ± 7.1 years and controls: 74.7 ± 5.7 years; two sample t-test, P < 0.001), more likely to be APOE ε4 carriers (AD: 60% carriers vs controls: 27% carriers; Chi-squared test, P < 0.001), more likely to be females (AD: 64% female vs controls: 55% female; Chi-squared test, P < 0.001), and had fewer years of education (mean ± SD for AD: 9.4 ± 4.8 years and controls: 13.9 ± 4.7 years; two sample t-test, P < 0.001). Here, APOE is linked to Alzheimer disease.