There was a significant increase of total apoE in the Aβ+ compared with Aβ− group when taking all the diagnoses together (n = 1817, p < 0.001) (Fig. 1a), as well as when looking only at the subset consisting of clinically diagnosed AD, MCI, and CU individuals (n = 1431, p < 0.05) (Fig. 1b). Here, APOE is linked to Alzheimer disease.