Long-Term Change in BMI for Children with Obesity Treated in Family-Centered Lifestyle Interventions

Abstract

Introduction: Several evaluations of lifestyle interventions for childhood obesity exist; however, follow-up beyond 2 years is necessary to validate the effect. The aim of the present study was to investigate long-term weight development following children participating in one of two pragmatic family-centered lifestyle interventions treating childhood obesity.

Methods: This real-life observational study included Danish children 4-17 years of age classified as having obesity. Data from 2010 to 2020, from two community-based family-centered lifestyle interventions (designated hereafter as the Aarhus- and the Randers-intervention) were merged with national registers and routine health check-ups, including height and weight. Adjusted mixed effect models were used to model changes in body mass index (BMI) z score. We performed exploratory analyses of the development in BMI z-score within stratified subgroups of children treated in the interventions before investigating potential effect modifications induced by sex, age, family structure, socioeconomic, or immigration status.

Results: With a median follow-up of 2.8 years (interquartile range: 1.3; 4.8), 703 children participated in an intervention (445 the Aarhus-intervention; 258 the Randers-intervention) and 2,337 children were not invited to participate (no-intervention). Children in both interventions experienced a comparable reduction in BMI z-scores during the first 6 months compared to the no-intervention group (Aarhus-intervention: -0.12 SD/year and Randers-intervention: -0.25 SD/year). Only children in the Randers-intervention reduced their BMI z-score throughout follow-up (Aarhus-intervention vs. no-intervention: 0.01 SD/year; confidence interval [CI]: -0.01; 0.04; Randers-intervention vs. no-intervention: -0.05 SD/year; CI: -0.08; -0.02). In subgroup comparisons, combining the two interventions, family income below the median (-0.05 SD/year, CI: -0.02; -0.09), immigrant background (0.04 SD/year, CI: 0.00; 0.07), or receiving intervention less than 1 year (0.04 SD/year, CI: 0.00; 0.08) were associated with a yearly increase in BMI z score. In addition, effect modification analyses did not observe any interaction by sex, age, family structure, socioeconomic, or immigration.

Conclusions: Although the more dynamic intervention with longer duration obtained and sustained a minor reduction in BMI z score, the clinical impact may only be modest and still not effective enough to induce a long-term beneficial development in BMI in children with obesity.

Keywords: Community-based; Lifestyle intervention; Long-term; Obesity; Trajectories.

Fig. 1.

Annual change in BMI z-score for the Aarhus-intervention (dashed line) and the Randers-intervention (dashed-and-dotted line) expressed by a mixed effect model with linear splines (knots placed at inclusion, 6, 12, 36, and 120 months). The annual change in BMI z-score was subtracted the change of the no-intervention group, while the change for the no-intervention group was set to 0 (solid line). The model was adjusted for co-variables at inclusion.

Fig. 2.

Annual change in BMI z-score for the children with duration of the intervention for less than a year (dashed line) and duration for at least a year (dashed-and-dotted line) expressed by a mixed effect model with linear splines (knots placed at inclusion, 6, 12, 36, and 120 months). The annual change in BMI z-score was subtracted the change of the no-intervention group, while the change for the no-intervention group was set to 0 (solid line). The annual change in BMI z-score was adjusted for co-variables at inclusion.