The relationship between type 2 diabetes and dementia

The relationship between type 2 diabetes and dementia
British Medical Bulletin 2008 88(1):131-146; doi:10.1093/bmb/ldn042
Mark W. J. Strachan1, Rebecca M. Reynolds 2, Brian M. Frier 3, Rory J. Mitchell 4 and Jacqueline F. Price 4

1 Metabolic Unit, Western General Hospital, Edinburgh, UK
2 Endocrinology Unit, Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
3 Department of Diabetes, Royal Infirmary of Edinburgh, Edinburgh, UK
4 Department of Public Health Sciences, University of Edinburgh, Edinburgh, UK

Correspondence to: Dr M. W. J. Strachan, Metabolic Unit, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK. E-mail: mark.strachan@luht.scot.nhs.uk

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Introduction: The prevalence of type 2 diabetes and dementia are set to rise inexorably over the next 30–40 years. There are now substantial data to suggest that type 2 diabetes is associated with an increased risk of dementia.

Sources of data: This is a narrative review using data from individual studies and review articles known to the authors. A Medline search was also undertaken and reference lists were reviewed to identify additional relevant studies.

Areas of agreement: Type 2 diabetes is associated with an increased risk of both Alzheimer's and Vascular dementia, although the reality is that many affected individuals have mixed forms of dementia.

Areas of controversy: The mechanisms underpinning this association remain to be clearly delineated. Type 2 diabetes is a complex disorder and so it is likely that multiple different, synergistic processes may interact to promote cognitive decrements.

Growing points: Recent data suggest that glucocorticoids excess and elevated inflammatory markers may also have a role in the aetiology of diabetes-related cognitive impairment.

Areas timely for developing research: Large-scale, prospective epidemiological studies are now required to accurately delineate the pathogenesis of cognitive impairment in people with type 2 diabetes. These are underway and randomized trials of diabetes-specific interventions are also starting to include cognitive function as an outcome measure.

Keywords: Type 2 diabetes • cognition • dementia • vascular disease • glucocorticoids

Accepted for publication October 28, 2008.

Copyright © 2008 Oxford University Press