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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 doi: (Published 07 February 2018) Cite this as: BMJ 2018;360:k211
  1. Peymane Adab, professor of public health and chief investigator1,
  2. Miranda J Pallan, senior clinical lecturer1,
  3. Emma R Lancashire, Senior Research Fellow and trial co-ordinator1,
  4. Karla Hemming, senior lecturer in medical statistics and trial statistician1,
  5. Emma Frew, reader in health economics1,
  6. Tim Barrett, professor of paediatrics2,
  7. Raj Bhopal, Bruce and John Usher chair in public health3,
  8. Janet E Cade, professor of nutritional epidemiology and public health4,
  9. Alastair Canaway, Research fellow5,
  10. Joanne L Clarke, PhD student1,
  11. Amanda Daley, reader in behavioural medicine1,
  12. Jonathan J Deeks, professor of biostatistics1,
  13. Joan L Duda, professor of sport and exercise psychology6,
  14. Ulf Ekelund, professor of physical activity epidemiology and public health, and senior investigator scientist7 8,
  15. Paramjit Gill, clinical reader in primary care research1,
  16. Tania Griffin, research fellow1,
  17. Eleanor McGee, public health nutrition lead9,
  18. Kiya Hurley, PhD student1,
  19. James Martin, PhD student1,
  20. Jayne Parry, professor of policy and public health1,
  21. Sandra Passmore, health education consultant and education advisor10,
  22. K K Cheng, professor of public health and primary care1
  1. 1Institute of Applied Health Research, University of Birmingham, Birmingham, UK
  2. 2School of Clinical and Experimental Medicine, University of Birmingham; Birmingham, UK
  3. 3Edinburgh Migration, Ethnicity and Health Research Group, Usher Institute of Population Health Sciences and Informatics, The University of Edinburgh, UK
  4. 4Nutritional Epidemiology Group, School of Food Science and Nutrition, University of Leeds, Leeds, UK
  5. 5Warwick CTU, University of Warwick, Warwick, UK
  6. 6School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
  7. 7Cambridge MRC Epidemiology Unit, Cambridge, UK
  8. 8Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway
  9. 9Birmingham Community Healthcare NHS Trust, Birmingham, UK
  10. 10Services for Education, Birmingham, UK
  1. Correspondence to: P Adab, Public Institute of Applied Health Research, Murray Learning Centre, University of Birmingham, B15 2TT, UK p.adab{at}
  • Accepted 19 December 2017


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.


  • Contributors: All WAVES study trial co-investigators contributed to the development of the design for the WAVES study trial and had contributed to the intervention development as part of the BEACHeS Study. PA wrote the first draft of the paper and all authors contributed to critical revisions. PA, MP, and KKC planned the overall design of the trial. ERL coordinated all aspects of the trial, oversaw data collection, collation, and cleaning, and contributed to data analysis. She also contributed to the first draft of the manuscript. EF contributed to the design of the trial and analysis plan, and AC advised on study instruments and undertook some of the analysis. JJD and KaH contributed to sampling, sample size estimation, and the statistical analysis plan. JM undertook data analysis, supervised by KaH and with support from ERL. UE advised on physical activity measurements and related methods and oversaw the preparation of the physical activity data. JEC advised on dietary assessment and related methods and oversaw the CADET data preparation. KiH led data collection and analysis of dietary data. JLD advised on some of the psychosocial assessment methods. TB, PG, and RB advised on clinical measurement processes. RB and PG advised on aspects related to ethnicity. AD advised on the physical activity intervention component. SP advised on school recruitment and approaches to keeping schools engaged. EM advised on the dietary intervention components. JP advised on process evaluation, and TG designed the detailed methods for this. TG and JLC contributed to data collection and undertook analysis and interpretation of the process evaluation. The final manuscript was read and approved by all authors. PA, ERL, and MP are guarantors.

  • Funding: This study was funded by the National Institute for Health Research (NIHR) Health Technology Assessment Programme (project reference No 06/85/11). The funder had no role in study design, data collection, data analysis, data interpretation, or writing of the report. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication. The University of Birmingham holds the relevant insurance policy for this study and acted as the main sponsor. The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the Health Technology Assessment, NIHR, National Health Service, or the Department of Health. The funders have played no role in the design, collection, analysis, and interpretation of data, nor in the writing of the manuscript and in the decision to submit the manuscript for publication.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: The trial was approved by NHS Research Ethics Service Committee West Midlands, The Black Country (NHS REC No 10/H1202/69).

  • Data sharing: Requests for access to data from the WAVES study should be addressed to the corresponding author at p.adab{at} All the individual participant data collected during the trial (including the data dictionary) will be available, after deidentification, immediately after publication with no end date. The study protocol has been published. All proposals requesting data access will need to specify how it is planned to use the data, and all proposals will need approval of the trial co-investigator team before data release.

  • Transparency: The guarantors (PA, ERL, and MP) affirm that the manuscript is an honest, accurate, and transparent account of the study bring reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

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