Associations between 24-hour movement compositions and cardiometabolic health in children and adolescents: a five-part compositional analysis using data from the International Children's Accelerometery Database (ICAD).

Objectives: The benefits of physical activity (PA) and the negative impacts of sedentary time (SED) on health in youth are well established. However, uncertainty remains surrounding how PA and SED jointly influence cardiometabolic risk (CMR) factors. The aim of this study was to determine the joint influence of SED, light-, moderate- and vigorous-intensity PA (LPA, MPA and VPA), and sleep on CMR factors using five-part compositional analyses. Methods: Data were pooled from 16 cohort studies comprising 22 474 children and adolescents from the International Children's Accelerometery Database. PA was measured using hip-mounted accelerometers with sleep self-reported. CMRs included body mass index (BMI), waist circumference (WC), systolic and diastolic blood pressure, fasting high- and low-density lipoprotein cholesterol, triglycerides, insulin and glucose. Time spent for sleep, SED, LPA, MPA and VPA was analysed using a compositional linear regression model. Results: The overall PA composition explained between 3.0 and 27.0% of the variance in CMR factors after accounting for age, sex, ethnicity and seasonal variation. However, when movement behaviours were explored in isolation, only sleep was associated with all CMR factors. In girls, compositions with 10 min more VPA were associated with a 2.5-4.4% greater BMI and WC. However, 10 min reallocations of time in boys had no impact on any CMR factor. Conclusion: These findings highlight that sleep and VPA are significantly associated with all CMR factors in youth, and therefore specific recommendations are needed to improve the current, and future, health of children and adolescents.