In a large observational study involving 176,250 participants, antidiabetic agents, including metformin, dipeptidyl peptidase-4 inhibitor (DPP-4i), glucagon-like peptide-1 (GLP-1) analogues and sodium glucose cotransporter 2 inhibitors (SGLT2i), significantly reduced the risk of dementia in T2DM [22]. This evidence concerns the gene DPP4 and type 2 diabetes mellitus.