The role of early and later response on overall outcomes in school-based obesity intervention

Authors: ARLINGHAUS, KATHERINE - University Of Houston; O'CONNOR, DANIEL - University Of Houston; LEDOUX, TRACEY - University Of Houston; HUGHES, SHERYL - Children'S Nutrition Research Center (CNRC); JOHNSTON, CRAIG - University Of Houston

Submitted to: Obesity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/3/2020
Publication Date: 11/22/2020
Citation: Arlinghaus, K.R., O'Connor, D.P., Ledoux, T.A., Hughes, S.O., Johnston, C.A. 2020. The role of early and later response on overall outcomes in school-based obesity intervention. Obesity. 29(1):177-183. https://doi.org/10.1002/oby.23040.
DOI: https://doi.org/10.1002/oby.23040

Interpretive Summary: A primary goal of obesity treatment during childhood is to prevent adult obesity and associated physical and psychological comorbidities. Addressing obesity before adulthood has multiple advantages because youth are still growing and developing. Rapid weight loss is not recommended for pediatric populations; substantial improvement should generally take 6 months to a year to achieve. As most pediatric interventions are shorter than a year, there is an inherent expectation that weight-related outcomes are maintained or will continue to improve following the active intervention. Moreover, improvements in weight outcomes during the first part of an intervention consistently predict overall long-term outcomes among pediatric populations. However, little is known about how changes in weight during the latter part of an intervention impact long-term outcomes. To address this gap, this study examined the relationship between early weight-related changes and later weight-related changes in 174 Hispanic middle school students participating in a school-based obesity intervention. Results showed that changes in weight outcomes during both the first and second halves of the intervention were independently associated with overall outcomes, while changes in the first half of the intervention were not associated with changes during the second half. Additionally, compared with weight changes in the first half of the intervention, changes in the second half were more strongly associated with 2-year outcomes. Understanding the contributions of weight changes that occur later in an intervention to overall outcomes may be particularly important for improving long-term outcomes. Continual monitoring of weight-related changes throughout interventions can inform in-time adaptations to interventions to improve the overall efficacy of obesity treatment.

Technical Abstract: Early response to obesity intervention consistently predicts long-term BMI reductions. However, little is known about how changes in weight at other times in an intervention may impact long-term outcomes. This study examined the relationship between weight-related changes that occurred early and later during an intervention and the association between these changes with overall outcomes. A secondary analysis of a school-based obesity intervention with replicated efficacy among Hispanic middle school students was conducted (n = 174). Linear regression models were developed in which first and second semester changes in BMI represented as a percentage of the 95th BMI percentile (%BMIp95) were separately used to predict overall %BMIp95 outcomes. First semester changes in %BMIp95 were used to predict subsequent %BMIp95 change (i.e., second semester). Changes in %BMIp95 during both the first and second semesters were independently associated with overall changes from baseline (e.g., at 24 months: first semester, beta = 0.59, P < 0.01; second semester, beta = 1.02, P < 0.001). First semester %BMIp95 change was not associated with second semester change (beta = -0.07, P = 0.32). Change at any point during the intervention was predictive of overall weight outcomes. Additional research is needed to understand patterns of weight changes throughout interventions to better understand long-term outcomes.