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

Objective: 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.

Methods: 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.

Results: 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.

Limitations: A major limitation is that clinically relevant depressive symptoms were assessed by a screening tool and the follow-up was short.

Conclusion: 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.