Study protocol for the evaluation of long-term effects of the school-based obesity prevention program Lekker Fit! (‘enjoy being fit’): a retrospective, controlled design

Abstract

IntroductionPreventive interventions to reduce overweight and obesity in childhood and adolescence are studied on their effectiveness worldwide. A number with positive results. However, long-term effects of these interventions and their potentially wider influence on well-being and health have been less studied. This study aims to evaluate the long-term effects of a multicomponent intervention in elementary school children targeting individual behaviour as well as environment (Lekker Fit!). The primary outcomeis body mass index and the secondary outcomes are waist circumference, weight status, physical fitness, lifestyle, psychosocial health and academic performance.Methods and analysisIn a naturalistic effect evaluation with a retrospective, controlled design adolescents in secondary schools, from intervention and non-intervention elementary schools, will be compared on a wide set of outcome variables. Data will be collected by questionnaires and through anthropometric and fitness measurements by trained physical education teachers and research assistants. Baseline data consist of measurements from the adolescents at the age of 5 years old and are gathered from preventive youth healthcare records, from before the intervention took place. Multilevel regression models will be used and adjusted for baseline measurements and potential confounding variables on the individual and environmental level. Furthermore, propensity scores will be applied.Ethics and disseminationThe study has been approved by the Medical Research Ethics Committee of the Erasmus Medical Centre, Rotterdam, The Netherlands (permission ID: MEC-2020-0644). Study findings will be disseminated in peer-reviewed journals and by conference presentations.Trial registration numberNL8799. Pre-results.

The long‐term effects of primary school‐based obesity prevention interventions in children: A systematic review and meta‐analysis

“…Natural experiments, quasi‐experimental and observational studies might be considered more feasible due to logistic or practical issues or can be considered more ethical than randomizing children for years in a control group withholding them from future interventions which are possibly effective. 12 , 13 In addition, using data from existing registries or ongoing cohort studies might be a way to derive insights on the long‐term effects of interventions beyond their intervention period. Furthermore, we recommend the use of predictive modelling combining intervention characteristics and individual participant data in future studies to more adequately determine the effect of different intervention components and in population subgroups.…”

“…In their review, Brown and colleagues (2019) encourage researchers to perform more long‐term follow‐up studies into the sustained effects of interventions. If RCTs are not feasible, researchers might turn to other types of designs, like natural experiments, quasi‐experimental and observational studies with comparison groups as these can also generate causal evidence with good external validity 12–14 . Insights in the long‐term effects of interventions are especially relevant for the transition from childhood into adolescence as the WHO highlighted that adolescence is a period of excessive weight gain because adolescents gain more freedom in food choices, while their physical activity levels often decrease 15…”

“…If RCTs are not feasible, researchers might turn to other types of designs, like natural experiments, quasi-experimental and observational studies with comparison groups as these can also generate causal evidence with good external validity. [12][13][14] Insights in the long-term effects of interventions are especially relevant for the transition from childhood into adolescence as the WHO highlighted that adolescence is a period of excessive weight gain because adolescents gain more freedom in food choices, while their physical activity levels often decrease. 15 To the best of our knowledge, a recent systematic review focusing on the long-term effects of primary school-based obesity prevention interventions in children is not available.…”

“…Furthermore, the longer the follow-up period, the more likely it will become that power or attrition issues arise that make it more difficult to reach sound evidence on effectiveness. Therefore, to assess the long-term impact of interventions, other types of study designs may give important insights as well.Natural experiments, quasi-experimental and observational studies might be considered more feasible due to logistic or practical issues or can be considered more ethical than randomizing children for years in a control group withholding them from future interventions which are possibly effective 12,13. In addition, using data from existing registries or ongoing cohort studies might be a way to derive insights on the long-term effects of interventions beyond their intervention period.…”