APOE and Obesity: The etiology of SAD is more complex and attributes to multiple risk factors such as age, brain injury, inefficient removal of Aβ, epsilon4 allele form of apolipoprotein E (APOE), midlife hypertension, high cholesterol, and obesity but none of these serves as a determining factor (Association, 2019; Dorszewska et al., 2016; Piaceri et al., 2013).