Compositional contributions and time reallocation of 24-hour movement behaviours and health-related quality of life among regional Australian children

Compositional associations between 24-hour movement behaviours (physical activity [PA], sedentary behaviour [SED], and sleep) and children’s health related quality of life (HRQoL) are unknown. This study aimed to use compositional data analysis (CoDA) to explore the relationship between device-measured 24-hour movement behaviours and children’s HRQoL. Hypothetically reallocating time in 24-hour movement behaviours and children’s HRQoL were also explored. This cross-sectional study included 268 primary school children (8-11 years) in South-West Victoria, Australia. Wrist-worn ActiGraph GT3X accelerometers assessed movement behaviours, and HRQoL was self-reported. CoDA was used to examine associations between movement behaviours and HRQoL, and an isotemporal substitution analysis explored hypothetical changes in HRQoL when reallocating 10 and 30 minutes between behaviours. On average, children spent 45.7% of their day sedentary, 27.2% in sleep, 22.1% in light-intensity PA (LPA), and 4.9% in moderate-to-vigorous PA (MVPA). A greater proportion of sleep relative to SED was positively associated with HRQoL (β = 11.274, 95% CI 5.456-17.093). Spending more time in MVPA relative to SED and LPA was related to higher HRQoL (β = 11.399, 95% CI 5.201-117.593); and LPA findings were mixed. Reallocating 10 minutes from SED, LPA and sleep to MVPA was associated with a higher HRQoL score (β =1.56; 95% CI 1.11, 2.01). Findings suggest that a greater proportion of MVPA, sleep, and lower SED were positively associated with HRQoL. Future interventions should prioritise reducing SED and promoting MVPA and sleep within the 24-hr movement behaviours. • MVPA was positively and significantly associated with HRQoL in this sample of regional Australian children. • Reallocating 10 minutes or more from sedentary behaviour to MVPA was related to a higher HRQoL score. • LPA had mixed effects, improving HRQoL only when paired with MVPA and sleep. • More sleep was beneficial to HRQoL when replacing sedentary behaviour.