Links Between Physical Frailty and Regional Gray Matter Volumes in Older Adults: A Voxel-Based Morphometry Study

Objectives: The relationship between physical frailty and regional gray matter volume in the brain was investigated among community-dwelling older Japanese people. Methods: Participants (N = 835; age range 65-89 years) were community-dwelling older adults in Obu City and Higashiura Town in Aichi Prefecture, Japan. Physical frailty was determined by the modified criteria of the Cardiovascular Health Study, which included weight loss, slowness, weakness, exhaustion, and low physical activity. Regional gray matter volumes were evaluated from 3-dimensional T1-weighted magnetic resonance images by statistical parametric mapping. The relationship between physical frailty and regional gray matter volume was analyzed with an analysis of covariance design using statistical parametric mapping adjusting for age, sex, and education level. Results: The voxel-based analyses showed that physical frailty per se was not significantly associated with any brain region. However, weakness was associated with reduced gray matter volumes in the hippocampus, amygdala, and fusiform gyrus, and slowness was associated with reduced gray matter volumes in the hippocampus, amygdala, fusiform gyrus, medial prefrontal and orbitofrontal cortex, inferior frontal gyrus, primary somatosensory cortex, insula, superior temporal sulcus, and cerebellum. Other components of physical frailty were not associated with the gray matter volumes in any regions. Conclusions and implications: The weakness and slowness components of physical frailty were linked to reduced gray matter volume in brain regions associated with not only physical mobility but also cognitive functions and social processes. This study addressed the underlying mechanisms in the progression of physical, cognitive, and social frailty, from the perspective of brain structures that are associated with frailty. (C) 2019 The Author(s). Published by Elsevier Inc. on behalf of AMDA - The Society for Post-Acute and Long-Term Care Medicine. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).