Cardiovascular disease, 24-h movement behaviors and all-cause mortality: a compositional mediation analysis based on a prospective cohort.

Objectives: We aimed to investigate how 24-h movement behaviors mediated the association between cardiovascular disease (CVD) and mortality, and to determine 24-h time-use patterns across different mortality risk strata for CVD patients. Methods: The study incorporated 90,858 UK Biobank adults (with a median age of 57 years, 56.2% female and 30.7% CVD patients) who undertook an accelerometer assessment. Cox compositional mediation models were used to determine the mediating effects of 24-h movement behaviors. The 24-h time-use patterns at varying risks were determined using risk stratification based on predicted mortality through isotemporal substitution models. Results: During a median follow-up of 13.4 years, 3047 deaths were recorded. The total indirect effect of CVD on mortality through 24-h movement behaviors was statistically significant with the mediation proportion being 16.9% for moderate-to-vigorous physical activity (MVPA) and 1.1% for sedentary behavior (SB). The 24-h time-use pattern of CVD patients with the low mortality risk was predicted to comprise 433, 606, 310, 91 min/day on sleep, SB, light-intensity physical activity and MVPA, respectively. Physical activity levels progressively decreased with rising mortality risk. CVD patients at high mortality risk were expected to gain 1.8 years of life by reallocating daily time to match the 24-h time-use pattern of those at low risk. Conclusion: The association between CVD and mortality is mediated by 24-h movement behaviors, particularly by MVPA and SB. For CVD patients, tailoring individual physical activity programs to 24-h time-use patterns at lower risk levels could serve as an effective behavioral intervention strategy for extending lifespan.