Associations of Academic Study- and Non-Study-Related Sedentary Behaviors with Incident Obesity in Children and Adolescents

<b>Objective</b>: To assess the associations between academic study- and non-study-related sedentary behaviors and the risk of overweight/obesity in children and adolescents, as well as their joint association with sugar-sweetened beverage (SSB) consumption. <b>Methods</b>: Sedentary behaviors and SSB consumption were assessed using self-reported questionnaires. Overweight/obesity were defined by age- and sex-specific body mass index cut-off values according to the criteria of "Screening for overweight and obesity among school-age children and adolescents" in China. Poisson regression with robust error variance was used to assess the associations of sedentary behaviors and/or SSB consumption with the risk of overweight/obesity, yielding relative risks (RRs) and 95% confidence intervals (CIs). The Shapley additive explanations (SHAP) method was used to rank the contribution of five specific sedentary behaviors to obesity risk. <b>Results</b>: Among 47,148 participants with a 3-year follow-up, longer durations of screen-related, academic study-related, and total sedentary time were each associated with a higher risk of overweight/obesity (adjusted RR (95% CI) per hour increment: 1.01 (1.00-1.02), 1.03 (1.01-1.06), and 1.02 (1.01-1.03)). After mutual adjustment, the associations of engaging in homework, attending tutorial classes, and using mobile electronic devices remained significantly associated with higher overweight/obesity risk. The SHAP summary plot shows that using mobile electronic devices, attending tutorial classes, and doing homework were the three most important sedentary obesogenic contributors. A significant interaction of age with sedentary time was found (<i>p</i> for interaction < 0.05). No significant interaction was found between SSB consumption and sedentary time. <b>Conclusions</b>: Excessive sedentary behaviors were associated with a higher risk of overweight/obesity, particularly due to mobile electronic device use, attending tutorial classes, and doing homework.