A cluster-randomised controlled trial to assess the effectiveness and cost-effectiveness of a childhood obesity prevention programme delivered through schools, targeting 6–7 year old children: the WAVES study protocol

Abstract

BackgroundThere is some evidence that school-based interventions are effective in preventing childhood obesity. However, longer term outcomes, equity of effects and cost-effectiveness of interventions have not been assessed.The aim of this trial is to assess the clinical and cost-effectiveness of a multi-component intervention programme targeting the school and family environment through primary schools, in preventing obesity in 6–7 year old children, compared to usual practice.MethodsThis cluster randomised controlled trial is set in 54 primary schools within the West Midlands, UK, including a multi-ethnic, socioeconomically diverse population of children aged 6–7 years.The 12-month intervention consists of healthy diet and physical activity promotion. These include: activities to increase time spent doing physical activity within the school day, participation in the ‘Villa Vitality’ programme (a programme that is delivered by an iconic sporting institution (Aston Villa Football Club), which provides interactive learning opportunities for physical activity and healthy eating), healthy cooking skills workshops in school time for parents and children, and provision of information to families signposting local leisure opportunities. The primary (clinical) outcome is the difference in body mass index (BMI) z-scores between arms at 3 and 18 months post-intervention completion. Cost per Quality Adjusted Life Year (QALY) will also be assessed. The sample size estimate (1000 children split across 50 schools at follow-up) is based on 90% power to detect differences in BMI z-score of 0.25 (estimated ICC ≤ 0.04), assuming a correlation between baseline and follow-up BMI z-score of 0.9. Treatment effects will be examined using mixed model ANCOVA. Primary analysis will adjust for baseline BMI z-score, and secondary analysis will adjust for pre-specified baseline school and child level covariates.DiscussionThe West Midlands ActiVe lifestyle and healthy Eating in School children (WAVES) study is the first trial that will examine the cost-effectiveness and long term outcomes of a childhood obesity prevention programme in a multi-ethnic population, with a sufficient sample size to detect clinically important differences in adiposity. The intervention was developed using the Medical Research Council framework for complex interventions, and outcomes are measured objectively, together with a comprehensive process evaluation.Trial registrationCurrent Controlled Trials ISRCTN97000586 (registered May 2010).

Modeling clustering and treatment effect heterogeneity in parallel and stepped‐wedge cluster randomized trials

“…In this example, we illustrate results from fitting models 1 and 2 to a set of data from a parallel CRT. The trial we choose as an example is a parallel cluster trial conducted in 53 schools (clusters) of a behavioral treatment to prevent obesity in school‐aged children . The outcome we consider here is the child's body mass index measured at the end of the trial.…”

Mapping the Paediatric Quality of Life Inventory (PedsQL™) Generic Core Scales onto the Child Health Utility Index–9 Dimension (CHU-9D) Score for Economic Evaluation in Children

“…The CHU-9D was initially designed for children aged 7-11 years; however, further research has now extended its use to children as young as 5 years [19][20][21] and to adolescents up to age 17 years [22]. The use of the instrument in 5-year-olds is currently being trialled [23].…”

Effects of a school-based intervention to reduce cardiovascular disease risk factors among secondary school students: a cluster randomized controlled trial

“…School health interventions programmes have shown consistent improvement on the general health status of students (15,16) and they are ideal places for health programmes (17,18). The WHO (19) estimates that these modifiable risk factors causes 80% of CVDs mainly physical inactivity, unhealthy diet, smoking, alcohol consumption and though CVDs occur in middle and adult ages the risk factors that cause the disease are learned during childhood and carried into adulthood.…”