The dynamic trends and causal effects of social participation and cognitive function among middle-aged and older adults: a longitudinal study in China

BACKGROUND: The aim of this study was to explore the developmental trajectories of social participation and cognitive function, as well as their interaction. METHODS: The study enrolled 6242 participants from the China Health and Retirement Longitudinal Study, with a mean age (SD) of 58.81 (7.94) years and 45.3% being female. Linear mixed models were used in the research to examine the association between social participation and cognitive function. Then, we performed latent growth curve models (LGCM) and cross-lagged panel models (CLPM) to explore the 5-year bidirectional causal relationship from 2015 to 2020. RESULTS: During the five-year follow-up (2015, 2018, & 2020), baseline social participation was related to subsequent cognitive function (β = 0.190, 95% CI, 0.138-0.244, p < .001), mental intactness (β = 0.092, 95% CI, 0.056-0.128, p < .001) and episodic memory (β = 0.099, 95% CI: 0.068-0.129, p < .001). Baseline cognitive function (β = 0.033, 95% CI, 0.021-0.045, p < .001), mental intactness (β = 0.035, 95% CI, 0.017-0.052, p < .001), and episodic memory (β = 0.050, 95% CI, 0.029-0.070, p < .001) were significantly related to subsequent social participation. LGCM showed that the level of social participation increases, while cognitive function remains stable, with the initial levels of both factors mutually influencing each other. The rate of change in social participation significantly predicts the rate of change in cognitive function, and vice versa. CLPM results further support the bidirectional causal relationship. CONCLUSION: Our study reveals the intricate dynamic association between social participation and cognitive function. The findings support the positive effects of social participation on healthy cognitive aging, while robust cognitive function enhances social participation in late midlife and older adulthood.