NIHR Signal A school-based obesity prevention programme was ineffective
Published on 10 April 2018
A school-based healthy lifestyle programme delivered to 6-7-year-old children and their parents made no difference to children’s weight, diet or activity levels. Around 1 in 4 remained overweight or obese.
The NIHR-funded year-long programme was delivered in 54 primary schools in one region of England. Teachers were trained to provide an additional 30 minutes of physical activity a day and deliver cookery workshops with parents each term. It also included activities with a local football club, Aston Villa.
Children in schools that took part were no less likely to be overweight or obese after 15 or 30 months, and their diet and exercise levels did not improve. Less than one in six schools managed to deliver the activity sessions as planned.
The results are similar to another recent trial of a lifestyle programme delivered to 9-10-year-olds. Both suggest that changes to reverse the tide of childhood obesity will have to take place in wider society, not just in schools, to have the desired effect.
- Public Health, Obesity and nutrition, Physical therapy, Schools and colleges
Why was this study needed?
The Health Survey for England 2016 showed that 28% of children aged 2-15 were overweight or obese. Less than a quarter achieve recommended physical activity levels. Obese children are likely to become obese adults, with the associated rise in conditions such as diabetes and cardiovascular disease. Obesity-related illness costs the NHS around £6 billion each year, with £350 million in social care expenditure.
The school environment provides the organisational and social structure with which to address the health behaviour of a large number of children from across the socioeconomic spectrum. Various studies have investigated school-based interventions with inconsistent effects, and many have had an insufficient long-term follow-up. Programmes vary widely in their components.
This makes implementation difficult. This trial aimed to address limitations of prior research, assessing the effects on a large sample of children over two years.
What did this study do?
The WAVES cluster randomised controlled trial was conducted in 54 West Midlands primary schools. Schools were assigned to the lifestyle programme or to continue normal activities.
The 12-month programme targeted 6-7-year-old children in Year two. It was based on existing evidence of what was likely to work and involved:
- an additional 30 minutes of physical activity each day
- a family cooking workshop each term
- in collaboration with local Aston Villa Football Club, three sessions of coaching in physical activities and two on preparing healthy meals, with weekly activity and healthy eating “challenges”
- information sheets about staying active during the holidays, with signposting to local facilities
Parents gave permission for 1,392 children (60% of those eligible) to be measured at the end of Year one. Measurements were repeated after 15 and 30 months for 60% and 55% of these children. Baseline BMI was slightly higher in intervention schools.
What did it find?
- There was no difference in children’s BMI z score between intervention and control schools at 15 months (mean difference [MD] -0.077 95% confidence interval [CI] −0.191 to +0.037) or 30 months (MD -0.042, 95% CI -0.163 to +0.080). Differences are adjusted for baseline BMI and other socioeconomic factors. The z score shows how many standard deviations a child’s BMI is above or below the average for their age and gender.
- There was no difference in the likelihood of children being overweight or obese at 15 months (risk difference adjusted for baseline BMI -0.013, 99% CI −0.075 to +0.071) or at 30 months (+0.002, 99% CI -0.068 to +0.093). Neither was there a difference in waist circumference or body fat percentage. At baseline 22% of the intervention group and 20% of controls were overweight/obese, rising to 29% and 25%, respectively, by 15 months.
- There were no differences in total daily energy intake (measured by dietary questionnaire) or physical energy expenditure (measured by 24-hour activity monitor) at 15 or 30 months. Fruit and vegetable intake reduced while fat intake increased in both groups.
- Children taking part in the programme were no more likely to have problems with body image (a concern from some teachers in consultation before the programme), and their quality of life scores was no different.
- The schools had difficulty in delivering some of the programme components, particularly the daily physical activity requirement, achieved as intended by only 4 of 26 schools. One school dropped out completely. However, in general, the programme was well received by children, teachers and parents.
What does current guidance say on this issue?
NICE has public health guidance on planning and commissioning lifestyle weight management services for overweight and obese young people. Programmes for the person and their close family should focus on healthy eating, increasing physical activity and decreasing sedentary time. A tailored plan is advised to meet the needs of the individual. Multidisciplinary team input may include motivational techniques and positive parenting skills training.
NICE recommends that school nurses and those involved in delivering the National Child Measurement Programme (where BMI is measured in Reception and Year six) raise awareness of lifestyle weight management.
What are the implications?
Like the recent NIHR funded HeLP trial that provided a healthy lifestyle programme to Year five children, the results for younger children are disappointing.
It is possible that the low child follow-up and higher BMI in intervention schools could have reduced the ability to detect any differences and few schools managed to deliver the activity sessions as planned. But the lack of benefit across outcomes suggests that tackling the obesity crisis is beyond the scope of schools alone.
The health behaviour of young children is largely influenced by parents. While promoting healthy eating and activity at school is probably helpful, it’s not enough. Society-wide action – for example, the upcoming tax on sugar-sweetened beverages – may have more impact.
Citation and Funding
Adab P, Pallan MJ, Lancashire ER, et al. Effectiveness of a childhood obesity prevention programme delivered through schools, targeting 6 and 7 year olds: cluster randomised controlled trial (WAVES study). BMJ. 2018;360:k211.
This study was funded by the National Institute for Health Research (NIHR) Health Technology Assessment Programme (project reference No 06/85/11).
Adab P, Barrett T, Bhopal R, et al. The West Midlands ActiVe lifestyle and healthy Eating in School children (WAVES) study: a cluster randomised controlled trial testing the clinical effectiveness and cost-effectiveness of a multifaceted obesity prevention intervention programme targeted at children aged 6-7 years. Health Technol Assess. 2018;22(8):1-608.
Merton Council. Tackling Childhood Obesity Together. Annual Report of the Director of Public Health 2016-17. Merton: Merton Council; 2016-17.
NHS Digital. Health Survey for England. London: NHS Digital; 2016.
NICE. Obesity in children and young people: prevention and lifestyle weight management programmes. QS94. London: National Institute of Health and Care Excellence; 2015.
NICE. Weight management: lifestyle services for overweight or obese children and young people. PH47. London: National Institute for Health and Care Excellence; updated March 2017.
Wake M. The failure of anti-obesity programmes in schools. BMJ. 2018;360:k507.
Wyatt K, Lloyd J, Creanor S, et al. Cluster randomised controlled trial and economic and process evaluation to determine the effectiveness and cost-effectiveness of a novel intervention [Healthy Lifestyles Programme (HeLP)] to prevent obesity in school children. Public Health Res. 2018;6(1).
Promoting exercise and healthy eating in childhood makes sense. What does not make sense is expecting that doing so will result in detectable changes in body mass index (BMI).
We know that two-thirds of adults are now overweight and a quarter obese, but the majority of primary school children are not yet overweight, so why should they become thinner?
If the same amount of money had been devoted to a treatment programme for the less than 10% children of that age who will already be clinically obese, might that have produced the same or better overall effect?
Charlotte M Wright, Professor of Community Child Health / Consultant Paediatrician, University of Glasgow