A study of 6 to 7 year-old children carried out by NIHR-funded researchers found that school-based interventions alone are unlikely to improve childhood obesity. The results have informed the NHS and other public agencies about the most appropriate methods to prevent and manage childhood obesity.
Published: 17 May 2022
Health risks linked to childhood obesity
Childhood obesity remains a serious health risk for many children worldwide. In the UK, one in four children are overweight or obese when they begin school at the age of 4 years. This rises to one in three children by the time they leave primary school. Obesity in childhood is linked to many health conditions including asthma, diabetes and heart disease, as well as mental health and behavioural problems.
Children who are obese are also predisposed to obesity in adulthood, putting them at greater risk of ill health, disability and premature death than healthy-weight adults. In addition to the personal damage to people’s health, treating obesity-related illnesses costs the NHS approximately £6.1 billion per year.
Evidence shows that obesity rates double and socioeconomic differences in obesity widen during the primary school years; these increase even further in secondary school. Finding out which interventions can prevent or manage obesity in children has great potential to improve public health.
Schools play an important role in teaching children about healthy lifestyles as well as creating environments that encourage healthy eating and physical activity. Previous research has shown that longer-term interventions involving the school curriculum and altering children’s food and physical activity environments may reduce the number of overweight children. Providing support for teachers and involving children’s families and wider community were also more likely to be successful. However, weaknesses in the evidence have prevented schools being given firm recommendations about delivering obesity-prevention interventions.
The NIHR Health Technology Assessment (HTA) Programme therefore commissioned the West Midlands ActiVe lifestyle and healthy Eating in School children (WAVES) study to provide strong evidence about whether a diet and physical activity-based intervention can prevent childhood obesity in schools.
By identifying ways to prevent obesity in children, we have the potential to benefit children’s wellbeing, reduce the burden of chronic disease and premature death in adults, reduce health inequalities and benefit society. Schools offer an avenue for universal targeting of children. However, we need to ensure that the resources used to deliver health activities offered in schools are worthwhile and don’t displace other valuable school actions.
Professor Peymane Adab, Professor of Public Health at the University of Birmingham and lead investigator for the WAVES study
Wider support needed to tackle obesity
Building upon the promising results of previous studies, the WAVES study team evaluated an evidence-based intervention involving nearly 1500 children. They followed them for 18 months to detect any improvement in the children’s weight.
The study recruited 54 primary schools from the West Midlands to receive either the intervention or a control programme that did not offer any healthy eating or physical activity elements. The West Midlands region was specifically chosen for its socioeconomic, ethnic and cultural diversity to ensure the study’s findings were relevant across the UK.
Taking into account the opinions of parents, teachers, and local health, government and community members, the WAVES intervention had been designed to provide a health promoting environment through programmes incorporated within a school year. These included daily school activities, information for children and their families and motivation for children to follow a better diet and engage in more exercise. It also included training and practical sessions, such as cooking courses for the children with their families and additional school-time physical activity. Children also took part in a 6-week healthy lifestyle promotion programme run by a local football club and received information about local physical activity opportunities.
Twenty-four schools delivered the 12-month WAVES intervention to 6 and 7 year-old pupils, with 660 children’s weight status being recorded 3 and 18 months after the intervention ended. Their changes in weight status were then compared with those of 732 children at 28 control schools.
The results showed that at each follow up, children who attended intervention schools were not less overweight than children attending the control schools. Although feedback from the participants was positive, the evidence showed that school-based interventions alone are unlikely to have an impact on childhood obesity.
She’s willing to try more fruits and vegetables, that’s what I’m pleased with probably more, before she was quite picky with what she’d have, but now she is willing to try new things.
Parent of school child in the WAVES intervention group.
During the study, teachers noted that children’s families, communities, the media and the food industry may have stronger influences on their dietary and exercise habits than any school-based intervention. One teacher commented that: “I think we can only back up what’s happening at home - the food comes from home, so we can only try and assist parents in getting kids to eat nutritionally.”
As Professor Adab explained: “Schools are important settings for accessing children and their families but they are one of several levels of environments that influence behaviour. Future school-based interventions need to be integrated within a wider societal framework and supported by upstream interventions. This includes having supportive policies to promote social and environmental change.”
The Royal College of Paediatrics and Child Health, which works on a range of programmes to improve child health, supported this view during the UK Government’s Health and Social Care committee inquiry on childhood obesity. They commented that the WAVES results “highlighted the importance of strengthening measures that tackle the obesogenic environment alongside what can be delivered in schools”.
The WAVES study was one of the first trials to analyse the costs of delivering a school-based intervention to prevent childhood obesity. It found that the intervention was unlikely to be cost-effective in schools, although some of the lower-cost elements could support schools to deliver health and wellbeing education.
Influencing the direction of obesity research
The WAVES study generated new evidence to inform the NHS and other public agencies about the most appropriate methods to prevent and manage childhood obesity. For example, during the study, Professor Adab was an expert advisor for the NICE guidelines on Maintaining a healthy weight and preventing excess weight gain among children and adults and Weight management: lifestyle services for overweight or obese children and young people.
Following publication of the WAVES study, Professor Adab submitted evidence on the effectiveness of schools-based interventions to the Government’s Health and Social Care committee inquiry on childhood obesity. She has since joined the guidance committee of the Obesity Health Alliance, a collective of 40 organisations working to inform government policy on obesity.
Alongside the Health Education Service in Birmingham, the research team has developed a summary report of the WAVES study for use within schools. They also gave media interviews and spoke at international conferences and to school educators as part of a series of engagement activities to publicise the need for other approaches combined with school-based interventions to tackle childhood obesity.
This NIHR award led to investigation of an important research question, which has provided valuable information for health policy in the UK. In addition, the study has contributed to public health research capacity building through training of four doctoral students and assisting several post-doctoral researchers to progress to the next stage in their careers.
Professor Peymane Adab
Their findings led to the development of further research, with the WAVES team members securing additional funding of more than £3.4 million from the NIHR and other sources to further investigate childhood obesity and other school-based health research. For example, the NIHR has funded several more projects, including the adaption of weight management programmes for children from minority ethnic backgrounds (CHANGE study), an evaluation of school food standards in secondary schools and, most recently, an evaluation of how school smartphone use policies affect children’s wellbeing. Birmingham City Council has also funded an evaluation of the school Daily Mile programme project.
With international funding from the Guangzhou Municipal Health Bureau and Guangzhou Center for Disease Control and Prevention, Professor Adab and her colleagues are investigating the settings and factors influencing childhood obesity in China. This also led to a philanthropic donation from a Chinese pharmaceutical company (Zhejiang Yong Ning Pharmaceutical Co Ltd) to evaluate a school-based childhood obesity prevention programme in Guangzhou City in China. Professor Adab commented: “The team hope that sharing the lessons learned from our WAVES research in the UK will inform interventions to prevent and reduce childhood obesity in China and other countries.”
- The study was funded by NIHR’s Health Technology Assessment (HTA) Programme.
- More information about the study is available on the NIHR’s Funding & Awards website.