Ryan McGrath, Sheria G. Robinson-Lane, Mark D. Peterson, Ryan R. Bailey, Brenda M. Vincent

Understanding the role of muscle strength as a preventive factor for shorter-term declines in function may provide further insights into the disabling process. This study examined if muscle strength was associated with 2-year preservation of instrumental activities of daily living (IADL) function and activities of daily living (ADL) disability status in older Mexican Americans. Longitudinal, panel. Urban and rural households in the Southwestern United States. A subsample of 672 Mexican Americans aged at least 65 years was followed for 2 years. Muscle strength was assessed with a hand-held dynamometer. IADL and ADL were self-reported. Covariate-adjusted ordinal and multinomial logistic models were used to determine the association between handgrip strength and changes in IADL function, and ADL disability status over 2 years. Every 10-kg increase in handgrip strength was associated with 5% decreased odds [odds ratio (OR): 0.95; 95% confidence interval (CI): 0.92, 0.98] of experiencing a lost IADL function in 2 years. Likewise, every 10-kg increase in handgrip strength was associated with an 8% decreased odds (OR: 0.92; CI: 0.88, 0.97) for 2-year onset ADL disability, 12% decreased odds (OR: 0.88; CI: 0.83, 0.94) for 2-year ADL disability progression, and 7% decreased odds (OR: 0.93; CI: 0.89, 0.98) for 2-year ADL disability improvement, compared to those with no ADL disability at baseline and follow-up. Higher muscle strength was related to a lower risk for 2-year onset of IADL and ADL disability in older Mexican Americans. Future investigations are warranted to examine how potential mediators influence the association between muscle strength and function, to inform interventions aiming to retain function in vulnerable older adult populations.