Objective: This study investigates the association between gait speed and handgrip strength, and their combination, with developing depressive symptoms in community-dwelling older adults using longitudinal data from the ASPirin in Reducing Events in the Elderly (ASPREE) study.
Methods: Participants were community-dwelling older adults in Australia and the USA, aged 70+ years (65+ years for USA minorities) and followed for a median (interquartile) of 3.9 (2.3) years. Baseline handgrip strength (measured in kilogram-force using a hydraulic hand dynamometer) and gait speed (time to walk 3 meters) based on quantiles taking the worst quantile, Q1 for grip and Q5 for gait were exposure variables. Depressive symptoms were measured annually using the modified Center for Epidemiological Studies Depression (CES-D 10) scale with a cutoff 10+. A total of 18,156 participants (55.8% females) included in the analysis after excluding participants with CESD-10≥10 at baseline. Cox regression was used to estimate Adjusted Hazard Ratios (AHR) with 95% Confidence Intervals (CI) were reported after adjusting for socio-demographics, BMI, comorbidity, polypharmacy and lifestyle factors.
Result: Depressive symptoms were significantly associated with weak handgrip (AHR 1.15, CI (1.07-1.22), slow gait (1.22; (1.14-1.31) and both weak grip and slow gait (1.33; (1.19-1.48). Each kilogram-force increase in grip strength or one meter-per-second slowing in gait speed was associated with a 5% (0.95; (0.93-0.97)) decrease and 7.5% (1.075; (1.05-1.10)) increase in depressive symptoms, respectively.
Conclusion: The development of depressive symptoms was associated with poorer hand grip strength and gait speed in graded pattern, and the combination of these physical measures predicted worsening depressive symptoms. Being physically strong may serve as a protective factor for depression in older adults. This highlights the link between physical and mental health of older adults and informs potential clinical as well as public health prevention strategies for depression, particularly for older adults with declining physical capacity.