Tania Griffin

Process evaluation design in a cluster randomised controlled childhood obesity prevention trial: the WAVES study

BackgroundThe implementation of a complex intervention is heavily influenced by individual context. Variation in implementation and tailoring of the intervention to the particular context will occur, even in a trial setting. It is recognised that in trials, evaluating the process of implementation of a complex intervention is important, yet process evaluation methods are rarely reported. The WAVES study is a cluster randomised controlled trial to evaluate the effectiveness of an obesity prevention intervention programme targeting children aged 6-7 years, delivered by teachers in primary schools across the West Midlands, UK. The intervention promoted activities encouraging physical activity and healthy eating. This paper presents the methods used to assess implementation of the intervention.MethodsPrevious literature was used to identify the dimensions of intervention process and implementation to be assessed, including adherence, exposure, quality of delivery, participant responsiveness, context, and programme differentiation.ResultsMultiple methods and tools were developed to capture information on all these dimensions. These included observations, logbooks, qualitative evaluation, questionnaires and research team reflection.DiscussionData collection posed several challenges, predominantly when relying on teachers to complete paperwork, which they saw as burdensome on top of their teaching responsibilities. However, the use of multiple methods helped to ensure data on each dimension, where possible, was collected using more than one method. This also allowed for triangulation of the findings when several data sources on any one dimension were available.ConclusionsWe have reported a comprehensive approach to the assessment of the implementation and processes of a complex childhood obesity prevention intervention within a cluster randomised controlled trial. These approaches can be transferred and adapted for use in other complex intervention trials.Trial registration numberISRCTN97000586

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.

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).

Teacher Experiences of Delivering an Obesity Prevention Programme (The WAVES Study Intervention) in a Primary School Setting.

Objective: There has been a wealth of childhood obesity prevention studies in school-based settings. However, few have investigated the experiences of school staff charged with delivery of such programmes. This study aimed to elicit teachers’ experiences of delivering a childhood obesity prevention programme for children aged 6–7 years. Design: Descriptive-interpretive qualitative study. Setting: Primary schools participating in the UK West Midlands ActiVe lifestyle and healthy Eating in School children (WAVES) study. Method: In all, 14 teachers were recruited from 12 primary schools. Semi-structured interviews were conducted and data analysis was guided by the Framework Approach. Results: Teachers recognised the importance of obesity prevention in primary schools. They reported positively on aspects of the intervention, in particular its flexibility and the ready-prepared materials. Time constraints and gaining support of parents were seen as key challenges to intervention delivery. Conclusions: Delivering an obesity prevention programme in school is feasible but challenging for teachers. Our findings suggest that to maximise the likelihood of delivery, interventions should be hands-on, easy to manage and flexible to the needs of individual schools. The perceived importance of the promotion of healthy lifestyle behaviours by schools was evident, but teachers felt restricted in the resources that could be devoted to achieve and encourage this. National combined with local level direction and support for healthy lifestyles in children would help schools to give this the priority it requires.

Effectiveness of a childhood obesity prevention programme delivered through schools, targeting 6 and 7 year olds: cluster randomised controlled trial (WAVES study)

Abstract Objective To assess the effectiveness of a school and family based healthy lifestyle programme (WAVES intervention) compared with usual practice, in preventing childhood obesity. Design Cluster randomised controlled trial. Setting UK primary schools from the West Midlands. Participants 200 schools were randomly selected from all state run primary schools within 35 miles of the study centre (n=980), oversampling those with high minority ethnic populations. These schools were randomly ordered and sequentially invited to participate. 144 eligible schools were approached to achieve the target recruitment of 54 schools. After baseline measurements 1467 year 1 pupils aged 5 and 6 years (control: 28 schools, 778 pupils) were randomised, using a blocked balancing algorithm. 53 schools remained in the trial and data on 1287 (87.7%) and 1169 (79.7%) pupils were available at first follow-up (15 month) and second follow-up (30 month), respectively. Interventions The 12 month intervention encouraged healthy eating and physical activity, including a daily additional 30 minute school time physical activity opportunity, a six week interactive skill based programme in conjunction with Aston Villa football club, signposting of local family physical activity opportunities through mail-outs every six months, and termly school led family workshops on healthy cooking skills. Main outcome measures The protocol defined primary outcomes, assessed blind to allocation, were between arm difference in body mass index (BMI) z score at 15 and 30 months. Secondary outcomes were further anthropometric, dietary, physical activity, and psychological measurements, and difference in BMI z score at 39 months in a subset. Results Data for primary outcome analyses were: baseline, 54 schools: 1392 pupils (732 controls); first follow-up (15 months post-baseline), 53 schools: 1249 pupils (675 controls); second follow-up (30 months post-baseline), 53 schools: 1145 pupils (621 controls). The mean BMI z score was non-significantly lower in the intervention arm compared with the control arm at 15 months (mean difference −0.075 (95% confidence interval −0.183 to 0.033, P=0.18) in the baseline adjusted models. At 30 months the mean difference was −0.027 (−0.137 to 0.083, P=0.63). There was no statistically significant difference between groups for other anthropometric, dietary, physical activity, or psychological measurements (including assessment of harm). Conclusions The primary analyses suggest that this experiential focused intervention had no statistically significant effect on BMI z score or on preventing childhood obesity. Schools are unlikely to impact on the childhood obesity epidemic by incorporating such interventions without wider support across multiple sectors and environments. Trial registration Current Controlled Trials ISRCTN97000586.

Parent and child perceptions of school-based obesity prevention in England: a qualitative study

BackgroundSchools are key settings for childhood obesity prevention, and the location for many intervention studies. This qualitative study aims to explore parent and child experiences of the WAVES study obesity prevention intervention, in order to gain understanding of the mechanisms by which the intervention results in behaviour change, and provide context to support interpretation of the main trial results.MethodsFocus groups were held with 30 parents and 62 children (aged 6-7 years) from primary schools in the West Midlands, UK. Data analysis (conducted using NVivo 10) was guided by the Framework Approach.ResultsThree over-arching themes were identified: ‘Impact’, ‘Sustainability’ and ‘Responsibilities’, under which sub-themes were determined. Participants were supportive of the school-based intervention. Parental involvement and the influential role of the teacher were seen as key ingredients for success in promoting consistent messages and empowering some parents to make positive behavioural changes at home. Parents recognised that whilst they held the primary responsibility for obesity prevention in their children, they faced a number of barriers to healthier lifestyles, and agreed that schools have an important role to play.ConclusionsThis study enabled us to better understand aspects of the WAVES study intervention programme that have the potential to initiate positive behaviour changes in families, and indicated that a combination of pathways influenced such changes. Pathways included: increasing capability through improving knowledge and skills of children and parents; increasing motivation through parental empowerment and role modelling; and the direct provision of opportunities to lead healthier lifestyles. Strategies to sustain behaviour changes, and the school role in supporting these, are important considerations.

Cultural adaptation of a children’s weight management programme for Bangladeshi and Pakistani families in the UK: a cluster-randomised feasibility study protocol

BackgroundGroup-based children’s weight management programmes are widely available in the UK and evidence shows that these are effective in the short-term. No programmes have been specifically developed to meet the cultural requirements of UK minority ethnic communities. South Asian children are a high-risk group for obesity and its consequences; therefore, the study aim is to adapt an existing weight management programme for children aged 4-11 years and their families to ensure cultural relevance to Pakistani and Bangladeshi communities, and undertake a feasibility study of the adapted programme.Methods/designPakistani and Bangladeshi families of overweight children who have been offered the existing children’s weight management programme in Birmingham, UK, will be invited to interviews and focus groups to explore their experiences and views of the programme. These data, together with existing literature and service provider information, will inform adaptation of the programme to be more culturally relevant to these families. The feasibility study will employ a cluster-randomised design, and will assess success of programme adaptation and feasibility of programme delivery. Planned programmes will be randomised to be delivered as the adapted programme (intervention) or the standard programme (comparator) with a 2:1 ratio. The primary outcome will be the proportion of Pakistani and Bangladeshi families completing the adapted programme. To assess recruitment, retention and data collection methods to inform a future trial, we aim to recruit 80 participants. A range of assessments will be undertaken with participants pre-, post- and 6-months post-intervention.DiscussionThis study addresses the identified need to provide children’s weight management programmes that are suitable for minority ethnic communities. Whilst the focus of the intervention adaptation is on Pakistani and Bangladeshi communities, the programme will be developed to be flexibly delivered to meet the cultural needs of communities of all ethnic compositions. The feasibility study will directly compare the adapted and existing weight management programmes, and will enable a comprehensive evaluation of the success of the adaptation. Essential information will also be gathered to inform the design and sample size calculation of a future trial to evaluate intervention effectiveness.Trial registrationISRCTN81798055, registered: 13/05/2014.

Fitness, physical activity and BMI in 5- to 6-year-old children; cross-sectional analysis on a sub-sample of children from the WAVES study, UK

Eating in the Absence of Hunger (EAH) is a behavioural trait referring to children’s susceptibility to eating when sated, in response to the presence of palatable snack foods. No study has yet examined whether television (TV) food advertising may provoke EAH behaviours in children. Research has found that exposure to TV food advertising increases food intake in children and that this increase is largest in the obese and thosewith higher habitual exposure to TV adverts. Therefore, this study aims to investigate the effects of TV food adverts in relation to differences in physiological state to observe EAH differences in children. Using a mixed-measures designwith one between-subjects factor (physiological state; hungry or sated) and one within-subjects factor (advert condition; food or non-food), 110 children aged 7–11 were tested on two occasions. Participants were exposed to each of the two types of adverts (in a counterbalanced order) before being given the opportunity to eat ad libitum from a selection of snacks. Height and weight measurements were taken and parental measures of habitual TV exposure collected. Preliminary data show a trend towards significance for increased consumption in the sated group after food advert exposure compared with toy adverts (10 kcal increase; p = 0.407). Sated overweight/obese children showed a significant increase in food consumption after watching TV food adverts compared with toy adverts (25 g increase; p = 0.048). This study may demonstrate that TV adverts serve as food cues triggering consumption in children who are already satisfied.