Adverse childhood experiences (ACEs) are associated with frailty, while the association with frailty state transitions and the role of social participation remain unclear. This study aimed to investigate the association between ACEs and frailty state transitions, alongside the moderating effect of social participation

Data from 9,621 adults aged 45 and older from the China Health and Retirement Longitudinal Study (2011–2020) were analyzed. Frailty was measured with the frailty index, while ACEs and social participation were measured with a validated questionnaire. The association between ACEs and frailty state transitions was estimated using multi-state models. An interaction analysis were used to examine the moderating effects of social participation.

Participants with higher ACEs scores (≥4) were associated with an increased probability of forward transition (robust to pre-frail, HR = 1.37, 95%CI: 1.21–1.54; prefrail to frail, HR = 1.39, 95%CI: 1.18–1.63) and decreased probability of backward transition (pre-frail to robust, HR = 0.64, 95%CI: 0.55–0.76). Additionally, participants with moderate and high level social participation were associated with an increased probability of backward transition (pre-frail to robust, HR = 1.11, 95%CI: 1.01–1.23; frail to pre-frail, HR = 1.17, 95%CI: 1.02–1.33, respectively). Social participation moderated the association between ACEs exposure and frailty (P for interaction <0.05), while participants with lower ACEs scores (1 and 2) and high social participation were associated with an increased probability of transition from frail to pre-frail (HR = 1.26, 95%CI: 1.04–1.89 and HR = 1.15, 95%CI: 1.08–1.69).

High ACEs scores were associated with an increased likelihood of adverse frailty development. Older adults with ACEs exposure might benefit from intervention strategies to improve social participation.