Higher physical activity is associated with greater myelin content in older adults with cerebral small vessel disease and mild cognitive impairment

Abstract

AbstractBackgroundMyelin loss is considered a marked feature of cerebral small vessel disease (cSVD). Although physical activity levels may exert protective effects over cSVD pathological changes, its specific relationship with myelin content in this population is unknown. Therefore, we investigated whether physical activity levels are associated with myelin content in community‐dwelling older adults with cSVD and mild cognitive impairment.MethodWe analyzed cross‐sectional data from older adults with cSVD and mild cognitive impairment in our laboratory. Myelin content was assessed using MRI with a multi‐echo gradient and spin echo T2 relaxation sequence, indexed as myelin water fraction (MWF). Physical activity levels were estimated using the Physical Activity Scale for the Elderly (PASE). Hierarchical regression models adjusting for total intracranial volume, age, sex, body mass index, and education were conducted to determine the associations between MWF and PASE. Significant models were further adjusted for white matter hyperintensity volume.ResultIndividuals (n = 102) with cSVD and mild cognitive impairment (mean [SD], age = 74.7y [5.5], Montreal Cognitive Assessment = 21.76 [3.2]), 63.7% female) were included. In adjusted models of tract‐specific cerebral white matter, physical activity was linked to higher MWF in the sagittal stratum (Unstandardized B [95% CI]: 0.014 [0.004 to 0.023], R2 change = 0.08, p = 0.004), anterior corona radiata (0.008 [0.000 to 0.015], R2 change = 0.04, p = 0.049), and genu of the corpus callosum (0.011 [0.002 to 0.020], R2 change = 0.05, pchange = 0.018). Similarly, physical activity also associated with MWF in whole‐brain white matter (0.007 [0.000 to 0.014], R2 change = 0.04, pchange = 0.046). White matter hyperintensity volume did not modify any of these associations.ConclusionPhysical activity may be one important component of maintaining myelin in older adults with cSVD. Future research should address whether myelin content is a sensitive neuroplasticity marker sensitive to physical activity changes or exercise interventions.