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Innov Aging
Innov Aging
innovateage
Innovation in Aging
2399-5300 Oxford University Press US 

10.1093/geroni/igaa057.748
igaa057.748
Abstracts
Session 2907 (Poster)
Mobility Disability
AcademicSubjects/SOC02600
Motor and Physical Function Impairments in Middle-Aged and Older Adults in the Baltimore Longitudinal Study of Aging
Cai Yurun 1 Tian Qu 2 Agrawal Yuri 3 Simonsick Eleanor 2 Schrack Jennifer 1 1 
Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States
2 
National Institute on Aging, Bethesda, Maryland, United States
3 
Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
2020 
16 12 2020 
16 12 2020 
4 Suppl 1 Program Abstracts from The GSA 2020 Annual Scientific Meeting “Turning 75: Why Age Matters”232 232
© The Author(s) 2020. Published by Oxford University Press on behalf of The Gerontological Society of America.2020This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.Abstract
Older adults experience motor function decline early in the disablement process, impacting daily activities and contributing to adverse health outcomes. Few studies have comprehensively examined the interrelationships among motor and functional impairments and investigated whether their contributions to mobility difficulty vary in well-functioning older adults. We examined direct and indirect associations of motor and physical function impairments with slow gait speed (<1.0m/s) and mobility difficulty using structural equation modeling (SEM) among 858 participants aged ≥50 years in the BLSA (mean age=74.1±10.6, 55% women). Motor and physical function tests included grip strength, knee extension strength, proprioception, finger tapping, standing balance (semi-, full-tandem, single-leg), repeated chair stands, and usual gait speed. Mobility difficulty was defined as self-reported difficulty in walking ¼ mile or climbing stairs. Motor and physical function impairments increased linearly with age, with 27.6% of participants having slow gait speed and 10.4% having mobility difficulty. Age-adjusted SEMs identified chair stands pace as the strongest predictor of slow gait speed, followed by latent factors of upper and lower extremity muscle strength and standing balance. Chair stands pace was the strongest predictor of mobility difficulty, followed by gait speed. Latent factors of muscle strength, proprioception, finger tapping, and standing balance were indirectly associated with mobility difficulty via gait speed. All models showed good model fit (RMSEA<0.05, CFI>0.95). These findings suggest components of strength and balance are among the most important contributors to poorer functional performance in mid-to-late life. Future longitudinal studies gauging the effect of change in these factors are warranted.