INS and Alzheimer disease: Noteworthy is the fact that there is a close epidemiological relationship between AD and T2DM (81% of cases of AD sufferers had either T2DM or impaired fasting glucose [195]) and that there are striking similarities in the protein misfolding and insulin signalling in both of these diseases, which could be due to the key role that insulin resistance plays in both AD and T2DM [18, 45].