Not all screens are equal: associations between screen-based sedentary behavior and physical activity in Chinese children and adolescents.

Background: Prior research has produced mixed results on the association between screen-based sedentary behavior (SSB) and physical activity (PA) in children and adolescents. Limited attention has been paid to how different types of SSB relate to PA across subgroups. Methods: This study analyzed data from 2,328 Chinese children and adolescents (aged 10-18) in the 2020 and 2022 waves of the China Family Panel Studies. Sufficient PA was defined as at least 60 min per session, five times a week. SSB types included online gaming, online shopping, short video watching, online learning, and WeChat use, categorized into never, occasional, and daily use. Logistic regression was used to explore associations between SSB and insufficient PA, with subgroup analyses by gender, educational level, and urban-rural residence. Results: Daily short video watching was associated with higher odds of insufficient PA among females (OR = 1.68), while occasional watching also increased the risk among elementary school students (OR = 1.61). Rural children and adolescents who occasionally engaged in online learning were more likely to report insufficient PA compared with those who never participated (OR = 1.32). In contrast, WeChat use was associated with lower odds of insufficient PA, particularly among males (OR = 0.19), rural children and adolescents (OR = 0.64), and junior high school students (OR = 0.59). No significant associations were found between online gaming or online shopping and insufficient PA. Conclusions: Different types of SSB show divergent associations with PA across subgroups. Short video watching and online learning may hinder PA, whereas moderate WeChat use appears to support it. Tailored, subgroup-specific intervention ns are needed to mitigate the risks of SSB and promote PA and health among children and adolescents.