Association between screen time, homework and reading duration, sleep duration, social jetlag and mental health among Chinese children and adolescents.

Objectives: To examine the associations of screen time, homework and reading duration, sleep duration, social jetlag with mental health in children and adolescents, as well as its gender differences.

Methods: From December 2023 to April 2024, a total of 62 395 children and adolescents were selected from 51 schools in 17 cities of China by stratified cluster sampling. Screen time, homework and reading duration, sleep duration, and social jetlag were calculated by answering the questions about watching TV time, playing smartphones time, doing homework time, reading extracurricular books time, bedtime, wake-up time, and nap time during weekdays and weekends. Mental health was assessed by the Revised Mental Health Inventory-5 (MHI-5). The generalized linear model was used to determine the association between screen time, homework and reading duration, sleep duration, social jetlag, and mental health in children and adolescents.

Results: The generalized linear model results showed that longer watching TV time, longer playing smartphones time, longer homework time, and greater social jetlag were correlated with poorer mental health in children and adolescents, while longer nighttime sleep duration, and longer daytime nap duration were correlated with better mental health. Moreover, in primary school and junior high school, we found that this association was stronger during the weekdays. However, in senior high school, this association was stronger during the weekends. After according to gender stratified, we found that the strength of this association was different in boys and girls at different study phases. Furthermore, our findings also revealed a significant quadratic relationship, indicating the association of better mental health with an optimal amount of sleep duration.

Conclusions: There was a significant association between screen time, homework and reading duration, sleep duration, social jetlag, and mental health in children and adolescents. This study has the potential to offer useful insights for the prevention and control of mental health issues in children and adolescents.