A 4 year follow-up study of cognitive functioning in patients with type 2 diabetes mellitus

E. van den Berg*, Y. D. Reijmer, Utrecht Diabetic Encephalopathy, J. de Bresser, R. P. C. Kessels, L. J. Kappelle, G. J. Biessels

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Type 2 diabetes mellitus is associated with moderate decrements in cognitive functioning, mainly in verbal memory, information-processing speed and executive functions. How this cognitive profile evolves over time is uncertain. The present study aims to provide detailed information on the evolution of cognitive decrements in type 2 diabetes over time.

Sixty-eight patients with type 2 diabetes and 38 controls matched for age, sex and estimated IQ performed an elaborate neuropsychological examination in 2002-2004 and again in 2006-2008, including 11 tasks covering five cognitive domains. Vascular and metabolic determinants were recorded. Data were analysed with repeated measures analysis of variance, including main effects for group, time and the group x time interaction.

Patients with type 2 diabetes showed moderate decrements in information-processing speed (mean difference in z scores [95% CI] -0.37 [-0.69, -0.05]) and attention and executive functions (-0.25 [-0.49, -0.01]) compared with controls at both the baseline and the 4 year follow-up examination. After 4 years both groups showed a decline in abstract reasoning (-0.16 [-0.30, -0.02]) and attention and executive functioning (-0.29 [-0.40, -0.17]), but there was no evidence for accelerated cognitive decline in the patients with type 2 diabetes as compared with controls (all p > 0.05).

In non-demented patients with type 2 diabetes, cognitive decrements are moderate in size and cognitive decline over 4 years is largely within the range of what can be viewed in normal ageing. Apparently, diabetes-related cognitive changes develop slowly over a prolonged period of time.

Original languageEnglish
Pages (from-to)58-65
Number of pages8
Issue number1
Early online date31 Oct 2009
Publication statusPublished - Jan 2010
Externally publishedYes


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