The Mediating Effect of 24-Hour Movement Behaviors on Mortality Risk in Chronic Kidney Disease: A Compositional Mediation and Life Expectancy Analysis

Background : To investigate the mediating effect of 24-hour movement behaviors on the relationship between chronic kidney disease (CKD) and mortality risk; additionally, to assess the health benefits of reallocating sedentary behavior (SB) with physical activity. Methods : This prospective cohort study included 88,795 participants (aged 43–78) from the UK Biobank with valid accelerometer data. A compositional mediation model assessed whether 24-hour movement behaviors mediate the CKD–mortality association. A flexible parametric hazards model was used to estimate life expectancy under various reallocation scenarios of 24-hour movement behaviors. Results : During a median follow-up of 8.10 years, 3673 participants met CKD criteria, and 3117 died. CKD increased all-cause mortality risk through greater SB and reduced light-intensity physical activity and moderate to vigorous physical activity (MVPA; hazard ratios = 1.040; 95% confidence interval, 1.030–1.050). Reallocating 20 minutes per day of SB to MVPA increased life expectancy by 1.70 years at age 45 (95% confidence interval, 0.51–4.34). Conclusions : Twenty four-hour movement behaviors partially mediate mortality risk in CKD, with MVPA showing the strongest protective effect. Interventions that reduce SB and increase MVPA can improve survival in CKD populations.