Accelerated cognitive decline in patients with type 2 diabetes: MRI correlates and risk factors

Abstract

Background Type 2 diabetes mellitus is associated with an increased risk of cognitive decline and dementia. We examined brain imaging correlates and vascular and metabolic risk factors of accelerated cognitive decline in patients with type 2 diabetes. Methods Cognitive functioning and brain volume as well as metabolic and vascular risk factors were assessed twice in 68 patients with no dementia with type 2 diabetes with a 4-year interval. Thirty-eight control participants served as a reference group. Volumetric measurements of the total brain, lateral ventricles and white-matter hyperintensities were performed on 1.5T magnetic resonance imaging scans. A regression-based index score was calculated on the basis of the reference group to assess changes in cognitive performance over time, adjusted for age, sex and estimated intelligence quotient. Brain volumes were compared between patients with and without accelerated cognitive decline. Logistic regression analyses were used to identify baseline risk factors for accelerated cognitive decline within the diabetes group. Results Accelerated cognitive decline was found in 17 (25%) patients with type 2 diabetes and was associated with a greater increase in ventricular volume [mean difference (95% confidence interval): 0.23% (0.08–0.38); p = 0.003] and white-matter hyperintensities volume [0.16% (0.05–0.27); p = 0.006] over the 4-year period. There were no specific vascular or metabolic risk factors associated with accelerated cognitive decline. Conclusions Accelerated cognitive decline in patients with type 2 diabetes was associated with progressive changes on brain magnetic resonance imaging, comprising both vascular damage and global atrophy. Exploration of vascular and metabolic risk factors revealed no specific determinants of accelerated cognitive decline