Besides, the MoCA score was significantly correlated with age (r = − 0.511, p < 0.001), BMI (r = 0.108, p = 0.0.048), education years (r = 0.395, p < 0.001), apolipoprotein A1/apolipoprotein B ratio (r = − 0.111, p = 0.042), and glycated hemoglobin (r = − 0.248, p < 0.001) in patients with T2DM. Here, APOB is linked to type 2 diabetes mellitus.