Associations between movement behaviors, sleep, and screen time exposure in middle childhood using multivariable modelling

Recreational screen time in early school-aged children is a growing public health concern, with implications for sleep, physical activity, and adiposity. While prior research has identified individual and environmental correlates of screen time, few studies have modeled these influences within a developmental and policy-relevant framework. Thus, this study aimed to examine behavioral, physical, and demographic correlates of categorized screen time among Portuguese children aged 6-10 years. A complete-case subsample of 307 Portuguese children (mean age: 8.5 ± 1.1 years) participated in a cross-sectional analysis. Multinomial logistic regression was employed to examine associations between parent-reported screen time categories and a multi-domain set of behavioral, sleep, anthropometric, and motor competence variables, including device-based measures of sedentary time, moderate-to-vigorous physical activity, and sleep parameters, as well as anthropometric indicators (body mass index, waist circumference) and motor competence. Higher sedentary time significantly increased the odds of belonging to higher screen time categories (OR = 1.13), while longer total sleep time showed a small inverse association (OR = 0.99). Higher sleep efficiency was also associated with greater screen time (OR = 1.07), which may reflect more consolidated sleep patterns in the context of high screen use. Sex was also independently associated with screen time category membership, with girls less likely to exhibit high screen time (OR = 0.41). These findings reinforce the interdependence of daily movement behaviors and highlight specific sleep and sedentary profiles linked to excessive screen time. The results support the application of the 24-h movement framework in public health strategies and underscore the importance of sex-sensitive, context-specific interventions targeting after-school routines and media environments.