Here, we have reviewed the dysregulation of the glymphatic pathway in diabetes-induced dementia, the effects of sleep on glymphatic system function, including the improvement of toxic peptide clearance, the enhancement of melatonin secretion, the regulation of APOE expression, the improvement of synaptic plasticity, the regulation of norepinephrine levels, and the alleviation of insulin resistance (11, 120, 128, 130, 170, 171) (Figure 1). This evidence concerns the gene APOE and dementia.