Elsevier

Diabetes & Metabolism

Volume 40, Issue 5, November 2014, Pages 331-337
Diabetes & Metabolism

Review
Update on cognitive decline and dementia in elderly patients with diabetes

https://doi.org/10.1016/j.diabet.2014.02.002Get rights and content

Abstract

Aim

This article is an update of the relationship between type 2 diabetes (T2D), cognitive dysfunction and dementia in older people.

Methods and results

The number of older patients consulting for diabetes who also exhibit cognitive difficulties is consistently growing because of the increased longevity of the population as a whole and, according to a number of studies, the increased risk of cognitive impairment and dementia in older diabetic patients. Many studies have demonstrated a link between poor glucose control and deteriorated cognitive function in diabetic patients. A history of severe hypoglycaemic episodes has also been associated with a greater risk of late-in-life cognitive deficits and dementia in patients with T2D. Several processes are thought to promote cognitive decline and dementia in diabetics. Based on both clinical and non-clinical findings, the factors most likely to alter brain function and structure are cerebrovascular complications of diabetes, alterations in glucose and insulin, and recurrent hypoglycaemia. Together with other diabetes complications, cognitive deficits contribute to functional impairment, increased frequency of depression-related symptoms, greater incidence of recurrent hypoglycaemia, poorer adherence to treatment and, finally, poorer prognosis, as evidenced by recent longitudinal studies.

Conclusion

Clinical guidelines have recently been devised for older diabetic patients, particularly those with cognitive deficits and a reduced capacity to self-manage. In the most vulnerable patients, specific treatment strategies have been proposed for glycaemic control to limit metabolic decompensation and avoid the risk of hypoglycaemia. Educational measures, provided mainly to maintain patient autonomy and avoid hospital admission, have also been adapted according to patients’ cognitive and functional status.

Introduction

In their everyday clinical practice, endocrinologists are facing a growing number of diabetic patients manifesting signs of cognitive decline and even full-blown dementia. The association is not surprising as these conditions share common features that are highly prevalent in the elderly population. In France, the prevalence of diagnosed diabetes increases with age to a maximum of 19.7% in men and 14.2% in women aged 75–79 years [1], while data from the PAQUID study suggest a 17.8% prevalence rate of dementia in people aged > 75 years [2]. The elevated frequency of cognitive dysfunction in elderly diabetics has been found in a majority of cross-sectional studies. Recently, 29% of the elderly patients with type 2 diabetes (T2D) included in the French GERODIAB study had impaired cognition at baseline [3]. Thus, cognitive dysfunction is a frequent clinical problem that requires early identification and integration into the management of diabetes in the elderly.

The purpose of the present report is to provide an update of the most significant findings concerning cognitive deficits and dementia in elderly patients with T2D.

Section snippets

Diabetes increases the risk of cognitive decline and dementia

Diabetes itself has been recognized as an independent risk factor for the development of cognitive impairment in large prospective population-based studies with follow-up durations of up to 18 years [4], [5], [6], [7], [8], [9]. In one extensive review [4], the annual rate of global cognitive decline, as measured by changes in Mini-Mental State Evaluation (MMSE) score [10], was found to be up to 1.5 times greater in diabetics than in non-diabetics. Some studies confirmed a greater risk of global

Cognitive decline is related to poor glycaemic control

Many studies have demonstrated a link between poor glucose control and deteriorated cognitive function in diabetes. Higher haemoglobin HbA1c levels were consistently associated with lower scores on cognitive testing [16], [17] and greater decline in cognition over time [18] in older adults with T2D. In contrast, cognitive benefits for working memory were achieved with improved glucose control in a short-term study of older diabetics [19]. More recently, dementia-free 55- to 80-year-old patients

Hypoglycaemia is important in diabetics with poor cognitive function

The incidence of hypoglycaemic episodes is important, but is probably underrecognized by diabetic patients as they advance in age: 33.6% of patients aged ≥ 70 years reported at least one hypoglycaemic episode; 3.3% have declared severe hypoglycaemia; and 0.6% have fallen into coma in the 6 months prior to inclusion in the GERODIAB study [3]. The link between the occurrence of hypoglycaemia and altered cognitive function has received much attention in older people with diabetes.

Cognitive impairment contributes to negative health outcomes

Cognitive deficits, in addition to other complications of late-life diabetes, can compromise patients’ daily activities and become potential barriers to self-care in diabetic patients. Cognitive fragility may also have social and economic consequences for such patients, and may contribute to significantly altered quality of life in this population.

Specific treatment strategies are required

As they advance in age, diabetic patients are more likely to develop comorbidities and functional impairment; they also usually have a higher prevalence of depression, and an increased risk of cognitive decline and dementia. For these reasons, a patient-centred approach that takes into account the presence of associated diseases and geriatric conditions, and the patient's needs and preferences, is a core principle underlying healthcare for elderly patients. This approach has been systematically

Conclusion

People with diabetes have an increased risk of cognitive dysfunction and dementia. Some researchers have even suggested that cognitive impairment and dementia be included in the list of late complications of diabetes. Diabetic patients with cognitive deficits are also at greater risk of presenting with severe hypoglycaemia. Because cognitive impairment in elderly diabetic patients can have a considerable impact on their daily life activities, functional autonomy and ability to manage

Disclosure of interest

Lyse Bordier and Bernard Bauduceau have received lecture fees from pharmaceutical companies that market drugs for the treatment of diabetes, namely, Bristol-Myers Squibb, Eli Lilly, MSD, Novo Nordisk and Sanofi-Aventis.

Jean Doucet is coordinator of the GERODIAB study. The study is being carried out with a grant from Novo Nordisk and Merck Serono, a research grant from the Société Francophone du Diabète (French-speaking Diabetes Society) and a national Programme Hospitalier de Recherche Clinique

Acknowledgments

The authors thank Catherine Soubrouillard (Eltium), who provided medical writing services on behalf of Lilly France.

References (46)

  • H. Ramaroson et al.

    PAQUID. Prevalence of dementia and Alzheimer's disease among subjects aged 75 years or over: updated results of the PAQUID cohort

    Rev Neurol

    (2003)
  • T. Cukierman et al.

    Cognitive decline and dementia in diabetes–systematic overview of prospective observational studies

    Diabetologia

    (2005)
  • F.P. Lu et al.

    Diabetes and the risk of multi-system aging phenotypes: a systematic review and meta-analysis

    PLoS One

    (2009)
  • K. Yaffe et al.

    Predictors of maintaining cognitive function in older adults: the Health ABC study

    Neurology

    (2009)
  • A.L. Christman et al.

    Glycated haemoglobin and cognitive decline: the Atherosclerosis Risk in Communities (ARIC) study

    Diabetologia

    (2011)
  • S. Artero et al.

    Risk profiles for mild cognitive impairment and progression to dementia are gender specific

    J Neurol Neurosurg Psychiatry

    (2008)
  • W. Xu et al.

    Accelerated progression from mild cognitive impairment to dementia in people with diabetes

    Diabetes

    (2010)
  • B. Winblad et al.

    Mild cognitive impairment–beyond controversies, towards a consensus: report of the International Working Group on Mild Cognitive Impairment

    J Intern Med

    (2004)
  • F. Irie et al.

    Enhanced risk for Alzheimer disease in persons with type 2 diabetes and APOE epsilon4: the Cardiovascular Health Study. Cognition Study

    Arch Neurol

    (2008)
  • J.A. Luchsinger et al.

    Improved diabetes control in elderly delays global cognitive decline

    J Nutr Health Aging

    (2012)
  • R.I. Shorr et al.

    Glycaemia and cognitive function in older adults using glucose-lowering drugs

    J Nutr Health Aging

    (2006)
  • K. Yaffe et al.

    Diabetes, glucose control, and 9-year cognitive decline among older adults without dementia

    Arch Neurol

    (2012)
  • C.M. Ryan et al.

    Improving metabolic control leads to better working memory in adults with type 2 diabetes

    Diabetes Care

    (2006)
  • Cited by (82)

    • Does computerized cognitive training improve diabetes self-management and cognition? A randomized control trial of middle-aged and older veterans with type 2 diabetes

      2023, Diabetes Research and Clinical Practice
      Citation Excerpt :

      Type 2 diabetes mellitus (hereafter, diabetes) has been associated with increased risk for cognitive decline, mild cognitive impairment (MCI), and dementia [1]. Individuals with both diabetes and cognitive impairment tend to have greater difficulties in managing their diabetes [2]. Even relatively low cognition in cognitively intact individuals can impair adherence to medications and overall disease self-management [3,4].

    View all citing articles on Scopus
    View full text