Progression of brain atrophy and cognitive decline in diabetes mellitus: a 3-year follow-up

Abstract

Objective: To investigate progression of MRI-assessed manifestations of cerebral degeneration related to cognitive changes in a population of elderly patients with diabetes mellitus (DM) compared to age-matched control subjects.

Methods: From a randomized controlled trial (PROSPER study), a study sample of 89 patients with DM and 438 control subjects without DM aged 70-82 years were included for brain MRI scanning and cognitive function testing at baseline and reexamination after 3 years. Changes in brain atrophy, white matter hyperintensities (WMHs), number of infarctions, and cognitive function test results were determined in patients with DM and subjects without DM. Linear regression analysis was performed with correction for age, gender, hypertension, pravastatin treatment, educational level, and baseline test results. In patients with DM, baseline MRI parameters were correlated with change in cognitive function test result using linear regression analysis with covariates age and gender.

Results: Patients with DM showed increased progression of brain atrophy (p < 0.01) after follow-up compared to control subjects. No difference in progression of WMH volume or infarctions was found. Patients with DM showed increased decline in cognitive performance on Stroop Test (p = 0.04) and Picture Learning Test (p = 0.03). Furthermore, in patients with DM, change in Picture Learning Test was associated with baseline brain atrophy (p < 0.02).

Conclusion: Our data show that elderly patients with DM without dementia have accelerated progression of brain atrophy with significant consequences in cognition compared to subjects without DM. Our findings add further evidence to the hypothesis that diabetes exerts deleterious effects on neuronal integrity.