Macro- and Microstructural Magnetic Resonance Imaging Indices Associated With Diabetes Among Community-Dwelling Older Adults

Cherie M. Falvey, MPH, Caterina Rosano, MD, Eleanor M. Simonsick, PHD, Tamara Harris, MD, MS, Elsa S. Strotmeyer, PHD, MPH,
Suzanne Satterfield, MD, DRPH, Kristine Yaffe, MD
Published online before print November 16, 2012, doi: 10.2337/dc12-0814

Diabetes Care November 16, 2012

Abstract
OBJECTIVES To 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 METHODS MRI 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 β values to estimate the cross-sectional 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 ROI. Models were adjusted for age, race, and sex; GMV values for ROI were also adjusted for total brain volume (TBV).

RESULTS In 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 with WMH. On microstructural measures, diabetes was associated with reduced FA for total white matter (P = 0.006) and greater MD 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.

CONCLUSIONS In 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.