Longitudinal trajectories of physical functioning among Chinese older adults: the role of depressive symptoms, cognitive functioning and subjective memory

BACKGROUND AND OBJECTIVE Maintaining physical functioning (i.e. mobility, activities of daily living [ADLs], instrumental activities of daily living [IADLs]) in older adults is essential for independent living. However, little is known about how longitudinal trajectories of physical functioning differ by varying levels of depressive symptoms, subjective memory impairment and cognitive functioning. We aimed to examine whether, and to what degree, the rate of change in physical functioning over time was associated with depressive symptoms, subjective memory and cognitive functioning. DESIGN A correlational longitudinal design. METHODS The sample included 5,519 older adults (mean age = 68.13 years) from the China Health and Retirement Longitudinal Study (three waves: 2011-15) who self-reported their depressive symptoms, subjective memory impairment and physical functioning. Cognitive functioning was assessed through interview-based tests. RESULTS There were significant increases in mobility impairment (β = 0.27, P < 0.001), ADLs impairment (β = 0.05, P < 0.001) and IADLs impairment (β = 0.03, P = 0.006) over time. Compared with the mean score at baseline in 2011, the mobility, ADLs and IADLs impairment increased by 13.32, 10.57 and 4.34% for every 2 years, respectively. Those with high depressive symptoms had accelerated rates of mobility (β = 0.212, P < 0.001), ADLs (β = 0.104, P < 0.001) and IADLs impairment (β = 0.076, P = 0.002). Those with poorer cognitive functioning had more rapid rates of mobility impairment. In contrast, those with differing levels of subjective memory impairment did not experience different physical functioning trajectories. CONCLUSIONS High depressive symptoms and poor cognitive functioning may be precursors to rapid declines in physical functioning. Proactive screening for these precursors may attenuate physical decline among Chinese older adults.