The joint trajectories of screen time, sleep, and physical activity during primary school and their links to demographic and socioeconomic status

BACKGROUND: The exploration of screen time, sleep duration, and physical activity is essential for developing effective programs that encourage healthy lifestyle habits in children. This study aimed to identify joint trajectories of recreational screen time, sleep, and physical activity in primary school-aged children, and to investigate the associations of demographic and socioeconomic factors with these trajectories. METHODS: Data were obtained from waves 3 (age 4-5), 6 (age 10-11), and 7 (age 12- 13) of the Longitudinal Study of Australian Children comprising 2064 children (47% girls). Group-based multi-trajectory modeling was used to identify latent clusters of children with similar movement behavior trajectories, and multinomial logistic regression models were used to examine the association of demographic and socioeconomic predictor variables, including child and parental characteristics, with these trajectory groups. RESULTS: Overall, a decline in physical activity and sleep duration, coupled with an increase in recreational screen time as children age was observed. Four distinct trajectory groups were identified and labelled "Most favourable' (30%), "Steady decline' (30%), "Steep decline' (27%), and "Least favourable' (11%). Boys, children with higher BMI, those from families with lower parental education, and those with limited access to outdoor space were more likely to follow less favourable behavioural trajectories. CONCLUSION: Well-timed interventions should be tailored to address the specific needs of boys, children with higher BMI, and those from families with lower parental education and limited access to outdoor space to improve their long-term health trajectories.