Physical Activity Predicts Higher Physical Function in Older Adults: The Osteoarthritis Initiative

Area of Science:

• Gerontology
• Rheumatology
• Physical Therapy

Background:

• Physical activity is known to mitigate mobility impairments in elderly populations.
• Osteoarthritis (OA) is a prevalent condition in older adults, often leading to functional limitations.

Purpose of the Study:

• To investigate the relationship between physical activity levels and the risk of subjective and objective physical function decline in adults with or at risk for OA.
• To explore how physical activity influences physical function outcomes in an aging population with knee OA.

Main Methods:

• Utilized data from the longitudinal Osteoarthritis Initiative, a prospective observational study.
• Classified 2252 adults (aged ≥60) into sex-specific quartiles based on the Physical Activity Score for the Elderly (PASE).
• Employed linear mixed models to analyze 6-year changes in self-reported health (SF-12 PCS), gait speed, Late-Life Function and Disability Index (LLFDI), and chair stand performance.

Main Results:

• While physical component scores (PCS) and gait speed declined over 6 years across all PASE quartiles, there were no significant differences in the rate of change between quartiles for either sex.
• Decline in PCS was observed in younger participants, and LLFDI scores decreased in those aged 70 and above.
• The association between physical activity and physical function was attenuated when knee extensor strength was included as a covariate.

Conclusions:

• Higher levels of physical activity are linked to better maintenance of physical function in older adults with or at risk for OA.
• Muscle strength significantly mediates the positive effects of physical activity on physical function.
• Encouraging regular physical activity is vital for preserving mobility and function in the elderly population, particularly those affected by OA.