Associations between trajectories of depressive symptoms and rate of cognitive decline among Chinese middle-aged and older adults: An 8-year longitudinal study

Abstract

Objective: To investigate the associations between trajectories of depressive symptoms and rate of cognitive decline among Chinese middle-aged and older adults.

Methods: A population-based cohort data from the Chinese Health and Retirement Longitudinal Study (CHARLS) were utilized. The cohort was followed up for 8 years and assessments of depressive symptoms and cognitive performance were conducted in 2011, 2013, 2015, and 2018. Group-based trajectory modeling (GBTM) was conducted to identify heterogeneous trajectories of depressive symptoms. Linear mixed models (LMMs) were performed to examine the associations between trajectories of depressive symptoms and rate of decline in global cognitive function, episodic memory, and executive function.

Results: Among 9264 middle-aged and older adults, five depressive symptoms trajectory groups were determined: constantly low (n = 3206, 34.6%), constantly medium (n = 3747, 40.5%), increasing (n = 899, 9.7%), decreasing (n = 929, 10.0%), and constantly high (n = 483, 5.2%). Individuals with increasing depressive symptoms exhibited the fastest decline in global cognitive function and episodic memory, followed by participants reporting constantly high or medium depressive symptoms. A significantly higher rate of decline in executive function was only observed among subjects who had increasing depressive symptoms in comparison with their counterparts with constantly low depressive symptoms. There was no significant difference in rate of cognitive decline between individuals with decreasing depressive symptoms and those demonstrating constantly low depressive symptoms.

Conclusion: Increasing depressive symptoms co-occurred with the steepest cognitive decline among Chinese middle-aged and older adults, which potentially suggested that interventions targeting to alleviating cognitive decline should be given priority among individuals with deterioration of depressive symptoms.

Keywords: Cognitive decline; Depressive symptoms; Population-based; Trajectory.