Macro-andmicrostructural magnetic resonance imaging indices associated with diabetes among community-dwelling older adults

Abstract

OBJECTIVEdTo better understand the association between diabetes and cognitive impairment, we evaluated macro-and microstructural brain MRI measures for the total brain and regions of interest (ROIs) in a group of community-dwelling elders with and without diabetes. RESEARCH DESIGN AND METHODSdMRI measures were obtained on 308 elders (mean age 83.3 years; n = 85 with diabetes) from the Health ABC Healthy Brain Substudy. We performed a series of linear regressions and used standardized b values to estimate the crosssectional association between diabetes and macrostructural (gray matter volume [GMV] and white matter hyperintensities [WMHs]) and microstructural (mean diffusivity [MD] and fractional anisotropy [FA])measures for the total brain and ROIs.Models were adjusted for age, race, and sex; GMV values for ROIs were also adjusted for total brain volume (TBV). RESULTSdIn multivariate-adjusted models, diabetes was associated with lower total GMV (P = 0.0006), GMV in the putamen (P = 0.02 for left and right), and TBV (P = 0.04) and greater cerebral atrophy (P = 0.02). There was no association withWMHs.Onmicrostructural measures, diabetes was associated with reduced FA for total whitematter (P = 0.006) and greaterMD for the hippocampus (P = 0.006 left; P = 0.01 right), dorsolateral prefrontal cortex (P = 0.0007, left; P = 0.002, right), left posterior cingulate (P = 0.02), and right putamen (P = 0.02). Further adjustment for stroke, hypertension, and myocardial infarction produced similar results. CONCLUSIONSdIn this cross-sectional study, elders with diabetes compared with those without had greater brain atrophy and early signs of neurodegeneration. Further studies are needed to determine whether these structural changes associated with diabetes predict risk of cognitive decline. Copyright © 2013 by the American Diabetes Association.