APOE and Alzheimer disease: Studies have shown that the mechanisms by which ApoE-ε4 increases the risk of AD are multifaceted, including amyloid β (Aβ)-dependent effects, that is, regulating Aβ levels, neurotoxicity and neuroinflammation, the development of neurons that are not related to Aβ-dependent effects, glucose metabolism, brain activity, and lipid metabolism [9].