The long-term mortality burden of childhood traumatic fractures: a mediation analysis of osteoarthritis and psychosocial pathways in older European adults

This study aimed to investigate the long-term associations between childhood hip or femur fractures and the risks of osteoarthritis (OA) and mortality in later life, and to examine the mediating roles of functional limitation, depressive symptoms, and social isolation in these relationships. It was a longitudinal cohort study using data from the Survey of Health, Ageing and Retirement in Europe (SHARE) (Waves 1–8), including 7,295 participants aged 50 and above. Propensity score matching was applied to balance baseline characteristics. Time-to-event outcomes were analyzed using Kaplan-Meier curves and Cox models. Mediation pathways involving Instrumental Activities of Daily Living (IADL), depressive symptoms (were measured by the EURO-D depression scale, hereafter EURO-D), and the Social Isolation Scale for Aging (SISA) were examined through structural equation modeling. Individuals with a history of childhood hip or femur fractures showed significantly increased risks of developing OA (HR = 1.39, 95% CI: 1.04–1.86) and premature mortality (HR = 1.67, 95% CI: 1.09–2.54). OA emerged as a key intermediate condition linking childhood fractures to increased mortality. Significant indirect effects were observed through IADL (19.3%), EURO-D (27.5%, marginal significance), and SISA (31.9%), indicating that functional decline, depressive symptoms, and social isolation are important mechanisms contributing to elevated mortality. Childhood fractures are associated with higher risks of OA and mortality in older adulthood, mediated through deteriorations in physical function, mental health, and social engagement. Holistic post-fracture care strategies addressing these multidimensional factors are essential to mitigate long-term health burdens.