Changes in Brain Volumetric Measures Associated With Type 1 Diabetes Depict an Evolutionary Adaptation Process to...

Type 1 diabetes mellitus has been associated with a significant risk of brain volume reduction and cognitive disorders, mainly affecting executive functioning and working memory. Therefore, an early impact of type 1 diabetes can be expected on volumetric measures and anatomic relationships among brain structures underlying these mental processes, as reflecting a process probably driven by developmental cognitive demands. With this aim, we compared volumetric measures and brain anatomical associations in young adults with type 1 diabetes and healthy controls.

Forty-one clinically well-controlled, right-handed type 1 diabetes patients aged 18-30 and with 10 or more years of disease evolution participated, along with forty-one healthy controls matched by age, sex, IQ, and years of schooling. They were all scanned with a 3-T MRI to obtain brain images with a voxel size of 1 mm³. The images were processed, and cortical gray and white matter were used to compute volumetric measures and cortical thickness, which were analyzed according to the corresponding segmentation map. Graph-theoretical analyses were also performed on adjacency resultant matrices.

Global cortical volumes did not significantly differ between the groups. However, subcortical gray matter volume was significantly lower in the diabetes group (M = 43.4 cm³, SD = 3.3) compared with controls (M = 45 cm³, SD = 3.8; t(80) = -2.04, p = 0.045, d = 0.45). Patients also showed reduced volumes in cerebellar white matter, vermis, and brainstem, as well as decreased volumes in several frontal and subcortical regions, including the putamen and thalamus. These changes were found to correlate meaningfully with longer diabetes duration and age at disease onset. Graph-theoretical analyses further revealed alterations in brain network topology in the diabetes group.

The results suggest that slight brain alterations affecting both brain microstructural integrity and typical organization early occur even in young patients with free-from-diabetes complications and clinically well-controlled type 1 diabetes. Moreover, these brain morphological changes appear to reflect the illness's distinctive impact on the developing brain, likely representing adaptive changes to address increasing cognitive and environmental demands.