Associations Between 24-Hour Movement Behaviors and Health-Related Quality of Life in East Asian Children

Background: It is important to investigate the combination of 24 h movement behaviors (24 h MB)—such as physical activity, screen time, and sleep—as children’s daily habitual behaviors significantly influence their health-related quality of life (HRQoL). However, such studies remain extremely limited in East Asia. This study aimed to examine whether adherence to the 24 h MB is associated with HRQoL among children from three East Asian countries. Methods: In this cross-sectional study, data were collected from primary school children aged 7–12 years in Japan (n = 786), China (n = 1246), and South Korea (n = 1011). HRQoL was assessed using the KIDSCREEN-27 questionnaire, while physical activity, screen time, and sleep duration were measured through a self-reported questionnaire survey. Results: Logistic regression analyses, adjusted for relevant covariates, confirmed significant associations with HRQoL subfactors including physical well-being, psychological well-being, social support, and peer relationships. Conclusions: Our findings highlight the critical relationship between adherence to 24 h MB and HRQoL in East Asian children, contributing valuable evidence to support integrated health promotion strategies in this region.