Type 2 diabetes mellitus and risk of Alzheimer's disease

Abstract

The evidences like biological and epidemiological support a link between type 2 diabetes mellitus (DM2) and Alzheimer's disease (AD). Persons with diabetes have a higher rate of cognitive decline and an increased risk of developing dementia of all types. Cognitive deficits in diabetic people get mainly affect the psychomotor efficiency areas like attention, learning and memory, mental ability, flexibility and speed, and executive function. The concrete epidemiological association has suggested the existence of a pathophysiological link. The factors of increased cognitive decline in DM2, however, are less clear. Increased atrophy of cortical and subcortical areas had clearly shows after controlling for diabetic vascular disease and inadequate circulation in cerebral areas.Most recent studies have focused on the role of insulin and insulin resistance as possible links between diabetes and AD. Disturbances in brain insulin signaling mechanisms may contribute to the molecular, biochemical, and histopathological lesions in AD. Hyperglycemia itself is a risk factor for cognitive dysfunction and dementia. Hypoglycemia may also have deleterious effects on cognitive function. Recurrent symptomatic and asymptomatic hypoglycemic episodes have been suggested to cause sub-clinical brain damage, and permanent cognitive impairment. Future trials are required to clarify the mechanistic link, to address the question whether cognitive decline may be prevented by an adequate metabolic control, and to elucidate the role of drugs that may cause hypoglycemic episodes.