Subclinical Brain Magnetic Resonance Imaging Abnormalities Predict Physical Functional Decline in High‐Functioning Older Adults

Abstract

Objectives: To determine whether severity of subclinical brain magnetic resonance imaging (MRI) abnormalities predicts incident self‐reported physical impairment or rate of decline in motor performance. Design: Longitudinal analysis, average follow‐up time: 4.0 years. Setting: Cardiovascular Health Study (CHS). Participants: CHS participants with modified Mini‐Mental State Examination (3MS) score of 80 or greater, no self‐reported disability, no history of stroke, and at least one assessment of mobility (n=2,450, mean age=74.4). Measurements: Brain MRI abnormalities (ventricular enlargement, white matter hyperintensities, subcortical and basal ganglia small brain infarcts), self‐reported physical impairment (difficulty walking half a mile or with one or more activities of daily living), and motor performance (gait speed, timed chair stand). Results: After adjusting for demographics, cardiovascular risk factors, and diseases, risk of incident self‐reported physical impairment was 35% greater for those with severe ventricular enlargement than for those with minimal ventricular enlargement, 22% greater for those with moderate white matter hyperintensities than for those with minimal white matter hyperintensities, and 26% greater for participants with at least one brain infarct than for those with no infarcts. Those with moderate to severe brain abnormalities experienced faster gait speed decline (0.02 m/s per year) than those with no MRI abnormalities (0.01 m/s per year). Further adjustment for incident stroke, incident dementia, and 3MS score did not substantially attenuate hazard ratios for incident self‐reported physical impairment or coefficients for decline in gait speed. Conclusion: Subclinical structural brain abnormalities in high‐functioning older adults can increase the risk of developing physical disabilities and declining in motor performance.