COVID-19 and diabetes mellitus in cognitive impairment: an undrawn relationship

Abstract Cognitive impairment is a potential short- and long-term disease consequence of COVID-19 virus, the exact mechanism is still in debate. One of their potential linking is with diabetes. Diabetes and COVID-19 infection have possible multiple common mechanisms that could ensue cognitive impairment as pulmonary microthrombi (silent hypoxia); endothelial dysfunction; cerebral vascular injury oxidative stress; renin-angiotensin-aldosterone system; and galectine and interferon responses. In addition, histological markers as amyloid AB plaques and neurofibrillary tangle of Tau protein are common in both pathologies. Despite of this evidence, diabetes mellitus and COVID-19 in cognitive impairment are establishing a bright light in terms of neurological progress. This article describes the relationship between diabetes mellitus and COVID-19 as potential cause of cognitive impairment.