Diabetes and cognitive function: An evidence-based current perspective

Abstract

Several epidemiological studies have clearly identified diabetes mellitus (DM) as a major risk factor for cognitive dysfunction, and it is going to be a major public health issue in the coming years because of the alarming rise in diabetes prevalence across the world. Brain and neural tissues predominantly depend on glucose as energy substrate and hence, any alterations in carbohydrate meta-bolism can directly impact on cerebral functional output including cognition, executive capacity, and memory. DM affects neuronal function and mental capacity in several ways, some of which include hypoperfusion of the brain tissues from cerebrovascular disease, diabetes-related alterations of glucose transporters causing abnormalities in neuronal glucose uptake and metabolism, local hyper- and hypometabolism of brain areas from insulin resistance, and recurrent hypoglycemic episodes inherent to pharmacotherapy of diabetes resulting in neuronal damage. Cognitive decline can further worsen diabetes care as DM is a disease largely self-managed by patients. Therefore, it is crucial to understand the pathobiology of cognitive dysfunction in relation to DM and its management for optimal long-term care plan for patients. A thorough appraisal of normal metabolic characteristics of the brain, how alterations in neural metabolism affects cognition, the diagnostic algorithm for patients with diabetes and dementia, and the management and prognosis of patients when they have this dangerous combination of illnesses is imperative in this context. This evidence-based narrative with the back-up of latest clinical trial reviews elaborates the current understanding on diabetes and cognitive function to empower physicians to manage their patients in day-to-day clinical practice.

Keywords: Diabetes mellitus; Dementia; Cognitive function; Antidiabetic medications; Hyperglycemia; Hypoglycemia

Core Tip: Diabetes mellitus (DM) is a huge risk factor for cognitive dysfunction especially when the glycemic control is inadequate with marked hyperglycemia and recurrent hypoglycemia. Apart from cognitive decline inherent to the disease, presence of other forms of dementia can adversely affect diabetes control and consequently, negatively impact the care of dementia and DM. Appropriate control of DM with a multidisciplinary team approach involving diabetologists, dementia specialists, dieticians and physiotherapists should improve the clinical outcomes of either disease. Judicious and evidence-based adjustments in the antidiabetic medications appropriately tailored for individualised diabetes care with due consideration of patient’s age, severity of dementia and other comorbidities should help to improve care of patients with diabetes and dementia.