Adiposity is inversely associated with hippocampal volume in African Americans and European Americans with diabetes

Abstract

Aims To assess associations between body mass index (BMI), waist circumference (WC), and computed tomography-determined volumes of pericardial, visceral, and subcutaneous adipose tissue with magnetic resonance imaging-(MRI) based cerebral structure and cognitive performance in individuals with type 2 diabetes (T2D). Methods This study was performed in 348 African Americans (AAs) and 256 European Americans (EAs) with T2D. Associations between adiposity measures with cerebral volumes of white matter (WMV), gray matter (GMV), white matter lesions, hippocampal GMV, and hippocampal WMV, cognitive performance and depression were examined using marginal models incorporating generalized estimating equations. All models were adjusted for age, sex, education, smoking, HbA1c, hypertension, statins, cardiovascular disease, MRI scanner (MRI outcomes only), and time between scans; some neuroimaging measures were additionally adjusted for intracranial volume. Results Participants were 59.9% female with mean (SD) age 57.7(9.3) years, diabetes duration 9.6(6.8) years, and HbA1c 7.8(1.9) %. In AAs, inverse associations were detected between hippocampal GMV and both BMI (β [95% CI] −0.18 [−0.30, −0.07], p=0.0018) and WC (−0.23 [−0.35, −0.12], p=0.0001). In the full bi-ethnic sample, inverse associations were detected between hippocampal WMV and WC (p<0.0001). Positive relationships were observed between BMI (p=0.0007) and WC (p<0.0001) with depression in EAs. Conclusions In patients with T2D, adiposity is inversely associated with hippocampal gray and white matter volumes.

Relationships of Clinical and Computed Tomography-Imaged Adiposity with Cognition in Middle-Aged and Older African Americans

“…Similar to our findings, other cohorts with similar prevalence rates of obesity and other vascular risk factors also reported no association between VAT and cognitive function (26,27). In contrast, studies that showed inverse associations between VAT and cognitive performance included participants with lower BMI and lower rates vascular risk factors (28,29).…”

Measures of Adiposity and Alzheimer’s Disease-Related MRI Markers: The Northern Manhattan Study

“…We did not find evidence of associations with hippocampal volume, which is in contrast to some studies [8,[43][44][45][46], but consistent with others [47,48]. Similarly to cortical thickness, the differences in findings across studies may be due to the timing of adiposity measurement.…”

Inflammasome NLRP3 Potentially Links Obesity-Associated Low-Grade Systemic Inflammation and Insulin Resistance with Alzheimer’s Disease

“…A recent study revealed that in non-diabetic AD patients, peripheral insulin resistance was independently associated with reduced hippocampal glucose metabolism and with lower grey matter volume, confirming the hypothesis of insulin resistance impact on AD pathology [ 56 ]. Moreover, neuroimaging studies of the brain reported significant correlations between the presence of T2DM, obesity, and/or peripheral insulin resistance with decreased hippocampal volume [ 67 , 68 ]. Nevertheless, AD is a brain form of diabetes in which both ligand (insulin and IGF-1) deficiencies and receptor resistances coexist and mediate functional impairments in signaling pathways, and this pathology is named type 3 diabetes [ 69 ].…”