24-h movement behavior composition associated with mental health in preschool children: a cross-sectional compositional data analysis

Background Mental health problems in preschool children represent an important public health concern. Understanding the associations between 24-h movement behaviors, including moderate-to-vigorous physical activity (MVPA), light physical activity (LPA), sedentary behavior (SB), and sleep (SLP), and mental health may help identify activity compositions associated with more favorable psychological outcomes. Objective This study aimed to examine the associations between reallocations of time among 24-h movement behaviors and mental health in preschool children aged 3–6 years and to identify activity compositions associated with more favorable mental health outcomes. Materials and methods This cross-sectional study included 850 Chinese preschool children aged 3–6 years. MVPA, LPA, and SB were objectively measured using ActiGraph GT3X-BT accelerometers, whereas SLP was assessed using structured parent- and teacher-reported questionnaires. Mental health outcomes, including total difficulties, internalizing and externalizing problems, and prosocial behavior, were assessed using the Strengths and Difficulties Questionnaire (SDQ). Compositional data analysis (CoDA) was performed using isometric log-ratio (ilr) transformations and multiple linear regression models. A one-to-three proportional time-reallocation approach was used to estimate changes in mental health outcomes associated with reallocating 10% of time in one behavior proportionally across the remaining three behaviors. In addition, optimal time-use analysis was conducted to identify 24-h movement compositions associated with more favorable mental health outcomes. Models were adjusted for age, gender, body mass index, residential district, parental education, and parental attitudes toward physical activity. Results An increase in MVPA was significantly associated with a reduction in Total Difficulties ( β = −1.658, p < 0.001) and Internalizing Problems ( β = −0.636, p = 0.027). An increase in SB was associated with an increase in Total Difficulties ( β = 1.615, p = 0.032), while an increase in SLP was significantly associated with a reduction in Total Difficulties ( β = −1.134, p = 0.034) and an improvement in Externalizing Problems ( β = −1.642, p = 0.009). Increases in MVPA or SLP, when proportionally replacing the other three behaviors, as well as the substitution of SB with other behaviors, were all associated with improvements in mental health ( p < 0.05). The model-derived 24-h movement behavior composition associated with more favorable mental health profiles in the study sample comprised 71 min of MVPA (55–85 min), 234 min of LPA (190–265 min), 514 min of SB (450–590 min), and 621 min of sleep (515–690 min). Conclusion Greater relative time spent in MVPA and SLP was associated with more favorable mental health outcomes among preschool children. The model-derived 24-h movement behavior composition identified in this study reflects associations within the observed sample and should not be interpreted as a causal relationship or a prescriptive intervention target. Longitudinal and intervention studies are needed to validate these findings.