To our knowledge, we conducted the first trial to evaluate the efficacy of an evidence-supported, family-based behavioral weight control program7, 10–13
in the management of severely obese school-aged children. Overall, our results document favorable 6-month (post-treatment) changes in percent overweight, and 12-month improvements in medical risk parameters among study participants. Specifically, children in the INTERVENTION condition showed a 7.58% decrease in percent overweight at the completion of acute treatment, which was significantly better than the 0.66% decrease observed in the USUAL CARE group.
The present short-term results are comparable to results reported in other randomized controlled trials. For example, a meta-analysis of 14 randomized controlled trials of lifestyle interventions for pediatric obesity20
documented an average decrease in percent overweight of 8.2% at post-treatment, which is comparable to the 7.58% decrease observed in the current study. However, the children in the present investigation were severely obese, whereas children in previous studies were likely to be moderately overweight.9
Another recent investigation did focus on an older group (approximately 12 years versus 10 years in the present study) of severely obese youth.21
In that study, children were randomized to a weight management program that included behavioral modification sessions and supervised exercise, or usual clinical management. Duration and intensity were greater than in the present investigation in that participants attended twice a week sessions for six months and bi-weekly sessions for an additional six months. At month 6, treatment was associated with significant decreases in BMI (−2.1 versus −0.7 in the current study) and insulin resistance.21
Thus, available data indicate that severely obese youth achieve short-term changes in BMI that are comparable to those observed in other behavioral interventions.
The changes in percent overweight were not well-maintained in the period after intervention in the current study. Child participants in INTERVENTION exhibited increases in percent overweight and BMI in the one-year period after weekly intervention while children in USUAL CARE maintained a stable degree of overweight, such that differences between study conditions in percent overweight did not differ significantly 12- or 18-month assessments. This finding stands in contrast to results reported in the literature,20
where, on average, the effects of family-based intervention were sustained over follow-up (ranging from one month to 5 years post-treatment). Weight loss maintenance in severely obese children is of particular importance given their level of medical risk. Results of the Savoye et al.21
study also raise concerns about weight loss maintenance in severely obese children. In that investigation, BMI among participants in the treatment group also increased during the second 6-months, despite ongoing bi-weekly intervention sessions.
Although impact on percent overweight was modest, INTERVENTION had positive effects on other health-related parameters that were sustained at 12-months. Specifically, children receiving family-based weight management when compared to those who received USUAL CARE evidenced significant improvements in waist circumference, systolic blood pressure, percent body fat, and total body fat. Waist circumference has been shown to be a significant predictor of abdominal fat and insulin resistance independent of BMI in youth.18
Thus the effects of INTERVENTION on cardiovascular risk factors are encouraging.
Several factors may affect the generalizability of study results. First, the study design did not control for time and attention, and thus we can not attribute outcomes to the specific components of the family-based intervention. Next, the prevalence of severe pediatric obesity varies by sex and race/ethnicity, with highest observed rates among Hispanic boys and Black girls.2
As there were no Hispanic youth in the current study, results may be most applicable to White and Black boys and girls. Further, youth who participate in university-based research programs may not be representative of those in the community. Finally, there was a significant proportion of missing data in the ITT analyses for medical risk factors, suggesting that replication is needed before firm conclusions about medical outcomes can be drawn.
In summary, a 6-month family-based behavioral weight management program was associated with significant decreases in percent overweight and improvements in medical risk factors in severely obese school-aged children. Although changes in percent overweight were modest given the severity of obesity, the significant health benefits of INTERVENTION suggest that further efforts to optimize the outcomes of family-based intervention programs are warranted. Session attendance was associated with significantly better child weight loss maintenance. Although future work is needed to understand the relation between attendance and weight control, the present findings suggest the potential importance of strategies to promote and facilitate program adherence. Similarly, larger reductions in adult BMI were associated with more successful outcomes, indicating that work to enhance adult role modeling and participation in child weight control programs may improve outcomes. Higher family income also was associated with short-term child decreases in percent overweight, and thus families with financial strain may benefit from strategies to reduce intervention cost burden. Finally, children with a lower percent overweight at study entry, even among an extremely overweight sample, exhibited better short-term decreases in percent overweight, and were less likely to be lost to follow-up at 18 months, suggesting that the heaviest children may require different strategies for engagement and treatment.
Available data suggest that maintenance of weight losses among severely obese children may be problematic. Thus, there is a compelling need to develop chronic care models for this high risk population. Effective longitudinal models are likely to require the sequential application of evidence-supported intervention components implemented over time to enhance and sustain weight control efforts and mitigate health risk. Family-based intervention will be an important component of any chronic care model. Data presented here suggest that future work should be directed at maximizing initial weight losses, promoting program participation, and identifying ways to support family behavior change.