All the participants were categorized into different subgroups according to median age (≥ 70 years/ < 70 years), sex (male/female), APOE genotype (APOE ε4 carrier/non-carrier), median BMI (≥ 24.7 kg/m2/ < 24.7 kg/m2), median education duration (≥ 12 years/ < 12 years) and medical history of stroke (yes/no), hypertension (yes/no), and diabetes (yes/no). Here, APOE is linked to diabetes mellitus.