INS and diabetes mellitus: Several studies reported that diabetes (type 2 diabetes mellitus) was indirectly associated with greater cognitive decline through association with lower cortical thickness at baseline [2]; increased the precursors of amyloid deposition in the brain and pancreas [3]; and damaged the downstream of the insulin signaling pathway in the brain, which leads to hyperphosphorylation of the tau protein in the brain [4], which are hallmarks of dementia neuropathology.