Investigators propose to study youth across the spectrum of body mass index (BMI) and dysglycemia. This approach will allow investigators to disentangle the relationship of key features of type 2 diabetes (T2D) risk (e.g. obesity) with intermediary physiologic changes (e.g. insulin resistance, inflammation, β-cell dysfunction and dysglycemia) that pose a risk for the brain. Investigators will determine which of these factors are most associated with differences in brain structure and function among groups, over time, and how these effects differ from normal neurodevelopment.
12-17 yrs. old at visit 1, 12-19 yrs. old at visit 2, Tanner II or above (determined through an exam by a pediatric endocrinologist or certified nurse practitioner trained in pediatric endocrinology), otherwise healthy except for obesity, <450 lbs. (due to MRI scanner limits), able and willing to lie flat within the MRI scanner and do cognitive testing, fluent in English.
Syndromic obesity, history of bariatric surgery, insulin treatment (metformin allowed if < 6 months) for T2D, contraindications for MRI (metal, claustrophobia), braces, pregnant (pregnancy test will be done on post-menarchal girls) or breastfeeding, inability to participate in cognitive testing due to sensory or language issues, intellectual disability, special education, pharmacologic treatment for Attention Deficit Hyperactivity Disorder (ADHD), prematurity (<36 weeks gestation), complications at birth, neurologic co-morbidities (e.g., seizures, stroke, head injury with >10 min loss of consciousness), significant psychiatric disorders (e.g., schizophrenia, bipolar disorder, current major depression), taking psychoactive medications (e.g., antipsychotics) that would interfere with testing or reporting illegal drug use. Self-reported smoking and alcohol use and length of time with obesity will be assessed by history (although these measures may not be fully reliable).
Pubertal youth ages 12-17 yrs. will be enrolled in a longitudinal design. Investigators chose to focus on the ages where there is the highest prevalence of impaired glucose tolerance (IGT) and T2D, reducing variability in neurodevelopmental and Tanner stages in the three cohorts. Investigators will follow participants for 21 months to ensure that enough time has passed to see changes in the stated outcome measures.
Case-control
Prospective
Observational
Other interventionInvestigators are observing brain health over time (21 months) in these groups
hippocampal volume
To determine hippocampal volumes, investigators will use the validated, objective and semi-automatic segmentation program Automated MRI Brain Volumetry System (volBrain). Hippocampal volumes will be obtained for each subject at each visit for primary analyses. Left and right volumes will be averaged, since lateralized findings are not hypothesized.
restricted fraction
Investigators will use Diffusion Basis Spectrum Imaging (DBSI) models on diffusion weighted images (DWI) to assess restricted fraction within the hippocampus and throughout white matter tracts.
Whole brain cerebral blood flow
Pseudo-continuous arterial spin labeling (pCASL) will be used to measure cerebral blood flow (CBF) implemented with an arterial spin labeling (ASL) sequence 228 and volume navigators (vNavs) to minimize motion artifact. Global CBF across pairs of frames will be scaled additively to the median value. Investigators will assess the number of voxels that statistically deviate from a normative value ('distributed deviating voxels') and compared between groups.
Declarative Memory
Investigators will use the total score from the Paired Associates Memory Test, an experimental cognitive task measuring delayed declarative memory
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Washington University School of Medicine
Lead sponsor
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Collaborator
