Impact of spousal caregiving on frailty index: longitudinal evidence from China Health and Retirement Longitudinal Study

Background and objective Research on the impact of spousal caregiving on caregivers' frailty remains limited. This study aimed to examine this association between spousal caregiving and frailty, explore how this association varies with care intensity, and investigate potential gender differences. Methods This study utilized data from four waves of the China Health and Retirement Longitudinal Study, including 3,987 participants aged 50 and above. Frailty was assessed using a composite mean score based on 41 indicators aligned with Rockwood's frailty criteria. These indicators included self-reported health, medically diagnosed conditions, medical symptoms, functional activities assessment, activities of daily living and instrumental activities of daily living. Samples were stratified by gender, and a growth curve model with random intercepts was employed to examine the associations between spousal caregiving status, care intensity and frailty trajectories over time. Results Among females, compared to non-caregivers, spousal caregiving was significantly associated with the increased frailty index when adjusted by all covariates, and frailty accelerated at a higher rate for caregivers. Providing care at all three intensity levels was associated with higher frailty, although depression attenuated these associations. Additionally, caregiving at lower intensity showed an accelerating rate of frailty progression over time. Among males, only providing higher-care intensity was associated with higher frailty. Conclusions This study highlights the importance of care intensity as well as the gendered effects of spousal caregiving on frailty - caregiving exacerbates frailty, particularly among females and among higher-intensity male caregivers. Our findings suggest the need for targeted supportive measures to alleviate psychological stress.