Abstract
BACKGROUND AND OBJECTIVES: With the intensification of ageing, cognitive frailty has become a major public health issue. The underlying mechanisms of the association between informal care and cognitive frailty were poorly understood. This study aimed to examine the mediating effect of social participation in the relationship between informal care and cognitive frailty among Chinese older adults. RESEARCH DESIGN AND METHODS: This research included 2,066 participants aged 60 and above from the China Health and Retirement Longitudinal Study (CHARLS). We conducted the logistic regression model and Karlson-Holm-Breen (KHB) analyses to test the mediating role of social participation in the relationship between informal care and cognitive frailty. RESULTS: After adjusting the confounders, three dimensions of informal care were negatively associated with cognitive frailty (financial support: β = -0.124, P = 0.043; emotional support: β = -0.149, P = 0.042; life care:β = -0.282, P = 0.015). Diversity and frequency of social participation were all mediated the association between financial support and cognitive frailty (diversity: P = 0.019, frequency: P = 0.013), as well as life care and cognitive frailty (diversity: P = 0.022, frequency: P = 0.018). However, the mediating effect of social participation on the association between emotional support and cognitive frailty was insignificant (diversity: P = 0.619, frequency: P = 0.957). DISCUSSION AND IMPLICATIONS: Informal care was associated with cognitive frailty among Chinese older adults. Diversity and frequency of social participation were all mediated the association between financial support and cognitive frailty, as well as life care and cognitive frailty. More attention should be devoted to promoting social participation among Chinese older adults with cognitive frailty, especially those who receive life care and financial support. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-025-06874-w.