APOE and hypertensive disorder: As presented in Table 4, among all participants, significant correlations were identified between the A1c level and the volume of left hippocampal tail (R = −0.334, p = 0.009), bilateral subiculum (RLeft = −0.291, p = 0.024; RRight = −0.271, p = 0.036), and bilateral molecular layer (RLeft = −0.307, p = 0.017; RRight = −0.283, p = 0.028) after adjusting for age, gender, body mass index, history of hypertension, level of cholesterol, duration of education, and the presence of ApoE4‐positive status.