Structural Gray and White Matter Differences in Patients With Type 1 Diabetes and Impaired Awareness of Hypoglycemia
Nicole Stantonyonge, Frederic Sampedro, Jorge Maté-Méndez, Saül Martínez‐Horta, Ana Chico, Beatriz Gómez‐Ansón
Abstract
CONTEXT: Type 1 diabetes (T1D) is associated with an increased risk of cognitive decline, where severe hypoglycemia (SH) and impaired awareness of hypoglycemia (IAH) may play a role. While there is evidence of a possible association between IAH and brain damage, the potential brain changes remain poorly characterized by magnetic resonance imaging (MRI). OBJECTIVE: To investigate whether there are structural brain differences in a group of T1D patients with IAH compared with normal awareness of hypoglycemia (NAH). DESIGN: General practice, population-based, cross-sectional study (July 2018 to July 2019). SETTING: Endocrinology Department, Hospital Santa Creu i Sant Pau. PARTICIPANTS: A total of 40 T1D patients (20 each with IAH and NAH) matched for age, sex, T1D duration, and education level. MAIN OUTCOME MEASURES: Using different neuroimaging techniques, we compared whole-brain gray matter (GM) and white matter (WM) differences. We used voxel-based morphometry and cortical surface area analysis methods to assess GM differences, and fractional anisotropy (FA) to assess WM differences. RESULTS: Compared with patients with T1D-NAH, patients with T1D-IAH had reduced GM volumes and cortical surface areas, especially in frontal and parietal regions (P < 0.05 corrected), and also showed reduced FA values in major WM tracts. The observed MRI differences correlated with both SH frequency and IAH severity. CONCLUSIONS: MRI for patients with T1D show that IAH is associated with brain changes involving both GM and WM. Further research is needed to elucidate whether the observed differences are a consequence of increased SH episode frequency and increased IAH severity.