Recent studies have shown differences in brain structure between adolescents with type 2 diabetes (T2D) and their nondiabetic peers. Compared to obese controls (OCs), global white matter (WM) and regional gray matter (GM) differences have been found. Our aim was to evaluate further for global and regional differences in GM, WM, and parenchymal (GM and WM combined) brain volume between youth with T2D and nondiabetic OCs. We compared 11 youth with T2D (mean age 17.1 ±2.0 years, mean HbA1c 8.6 ±2.5%) and 11 age, race and sex similar OCs (mean HbA1c 5.3 ±0.2%). Participants underwent high-resolution T1-weighted MRI scans, analyzed using voxel-based morphometry. Tissue volumes were normalized across participants by dividing by each individual’s intracranial volume (ICV). The normalized global volumes were compared between the two groups, and statistical significance was determined at p<0.05. For regional analyses, statistical significance for each voxel was established at p <0.05 using a family-wise error rate procedure, reporting only clusters with ≥200 contiguous voxels. Compared to OCs, adolescents with T2D had significantly lower parenchymal brain volume (parenchymal/ICV ratio 0.843 in T2D vs. 0.856 in OC, p=0.04). There were no significant differences in global GM (GM/ICV ratio 0.514 in T2D vs. 0.517 in OC, p=0.76) or global WM (WM/ICV ratio 0.329 in T2D vs. 0.340 in OC, p=0.10), although global WM did trend toward significance. In addition, there were 3 brain regions in the T2D group that had lower GM volume than OCs, and 2 regions in which the T2D group had greater GM volume. Adolescents with T2D show significantly lower parenchymal brain volume compared to age, race, and sex similar OCs. This difference may be attributable to lower WM volume, but a larger sample size is needed. No global GM differences were found between groups, but regional differences in GM were identified. These data support the hypothesis that, independent of obesity, structural brain differences may exist in adolescents with T2D.
J.M. Redel: None. M.W. DiFrancesco: None. G.R. Lee: None. L.M. Dolan: None. A.S. Shah: None.
Endocrine Fellows Foundation; Cincinnati Diabetes and Obesity Center; Cincinnati Children's