Prospective associations between depressive symptoms and cognitive functions in middle-aged and elderly Chinese adults

To examine prospective associations of clinically relevant depressive symptoms with cognitive functions and rates of cognitive decline among Chinese adults aged 45 years and older. Data was from the China Health and Retirement Longitudinal Study (CHARLS) with a follow-up of 4 years. Based on the Chinese version of 10-item Center for Epidemiologic Studies Depression Scale (CESD-10), clinically relevant depressive symptoms were defined with a CESD-10 score≥10 points. Cognitive functions were measured in three domains: episodic memory, mental status and global cognition. Linear mixed models were used to assess the associations between clinically relevant depressive symptoms and cognitive functions. A total of 7335 participants (50.10% men; mean age: 57.47) were included in analyses. Participants with clinically relevant depressive symptoms showed poorer episodic memory (β=-0.35; 95% CI:-0.41, -0.29), mental status (β=-0.48; 95% CI: -0.57, -0.39), and global cognition (β=-0.82; 95% CI: -0.94, -0.70) during the follow-up. Compared with counterparts, rates of decline in episodic memory, mental status, and global cognition increased by 0.04 (β=0.04; 95% CI: 0.02, 0.06), 0.06 (β=0.06; 95% CI: 0.02, 0.09) and 0.11 (β=0.11; 95% CI: 0.06, 0.15) units per year in participants with clinically relevant depressive symptoms. A major limitation is that clinically relevant depressive symptoms were assessed by a screening tool and the follow-up was short. More severe clinically relevant depressive symptoms were associated with poorer cognitive functions and moderately faster cognitive decline in episodic memory, mental status and global cognition in middle-aged and elderly Chinese adults.