Motivation in adolescents and caretakers undergoing a weight management program – longitudinal data from the cluster-randomized, motivation-focused STARKIDS trial

Background Motivation towards behavior change is an important determinant of long-term weight management. Previous research demonstrates that children’s and adolescents’ motivation can be increased through participation in weight management programs. However, little is known about motivational changes in caretakers of children and adolescents with overweight and obesity despite their recognized role as “agents of change” in pediatric weight management. The study aims to compare motivational changes in caretakers and adolescents between a group receiving a motivation-focused weight management program and a control group. Furthermore, predictors for motivational changes are unknown. Methods This study is a secondary analysis of the cluster-randomized STARKIDS trial. The intervention group received an 18-month motivation-focused weight management program, the control group received optimized treatment-as-usual. Motivation was assessed based on Transtheoretical Model, using the University of Rhode Island Change Assessment-Short, as well as the related parent-perspective version. Each of these instruments contains four subscales: Precontemplation, Contemplation, Action, and Maintenance. Linear mixed models with multiply imputed data were employed to evaluate changes within the subscales between pre- to post-intervention measurements and to compare these changes between the intervention and control group. A multiple linear regression was subsequently used to identify predictors of motivational change. Results Caretakers in the intervention group showed significantly greater changes on Maintenance subscale compared to caretakers in the control group at both T0-T1 and T0-T2 and trends for these changes on Action subscale. No group differences were found in adolescents. Among caregivers in the intervention group, multiple regression analysis for T0-T1 changes on Action subscale identified parent-reported adolescents’ obesity-related quality of life as significant negative predictor for an increase on Action stage. Conclusions This motivation-focused weight management program produced motivational gains at the Maintenance stage, supporting sustained behavioral change. Baseline obesity-related quality of life predicted motivational change, suggesting its value as a clinical marker for tailoring interventional approaches. Future research should explore distinct motivational trajectories to inform more individualized pediatric weight management strategies. Trial registration Preregistered in the German Clinical Trials Register (DRKS) DRKS000228 13 (acknowledged primary register of the World Health Organization) on 27 November 2020 (Universal Trial Number U111112549536).