24-hour movement behaviours and psychological health in young paediatric cancer survivors. A compositional data analysis from the iBoneFIT project

Young paediatric cancer survivors have compromised psychological health and tend to be more sedentary than their healthy peers. The main objective of this study is to examine the associations of 24-h movement behaviours (moderate-to-vigorous physical activity [MVPA], light physical activity [LPA], sedentary behaviour [SB] and sleep) with psychological well-being (happiness, optimism, positive affect, and self-esteem) and distress indicators (depression, anxiety and negative affect) in young paediatric cancer survivors by somatic maturity. This cross-sectional multicentre study included 116 participants (12.1 ± 3.3 years old; 42% female) from the iBoneFIT framework. Psychological well-being and distress indicators were assessed by questionnaires and time spent in movement behaviours by accelerometer. Participants were classified according to their somatic maturity (pre or peri/post-pubertal depending on the estimated years from peak height velocity). The adjusted models' coefficients were used to predict the effect of reallocating time proportionally across behaviours on the outcomes. Concerning well-being, our results indicate that reallocating time to LPA from the remaining movement behaviours (MVPA, SB, and sleep time) was positively associated with happiness (B = 1.545, p = 0.022) in the pre-pubertal group. Additionally, reallocating time to SB was positively associated with positive affect (B = 2.860, p = 0.006), whereas reallocating time to sleep time was negatively associated (B = −4.090, p = 0.005). In the peri/post-pubertal group, reallocating time to MVPA was positively associated with happiness and optimism (B = 0.778, p = 0.032 and B = 0.920, p = 0.008, respectively). Concerning psychological distress, reallocating time to LPA or SB was negatively associated with depression (B = −1.786, p = 0.032 and B = −2.294, p = 0.029, respectively), whilst reallocating time to sleep was positively associated with depression (B = 4.707, p = 0.002) in the pre-pubertal group. In the peri/post-pubertal group, reallocating time to MVPA was negatively associated with depression and anxiety (B = −0.779, p = 0.026 and B = −0.749, p = 0.014, respectively). These results underline the importance of promoting LPA and MVPA in pre-pubertal cancer survivors as well as MVPA in peri/post-pubertal cancer survivors to improve their psychological health.