JAMA Pediatr. 2021;175(3):251259. https://jamanetwork.com/journals/jamapediatrics/article-abstract/2773004
The authors report a cluster randomized clinical trial in 79 California schools, involving 28,641 students in grades 3 to 8. The intervention comprised school measurements of BMI and sending the results to parents, but this had no effect on BMI Z-scores after 1 year or 2 years of follow-up. There were mixed effects on adverse outcomes: the intervention increased weight dissatisfaction and peer weight talk, but the risk of concerning weight control behaviors was reduced.
Public health approaches to avoid and reduce childhood obesity are widely implemented in schools, often through nationwide statutory activities. For example, the UK National Child Measurement Programme follows a very similar approach to that tested in the current trial. However, few of these interventions are evaluated with the rigour applied by these authors. Not only did they show a lack of evidence that the programme is effective in reducing BMI, but they provided intriguing data on the potential harms. A thoughtful editorial on this paper discusses the pros and cons of BMI screening in schools, including the potential adverse impacts of weight stigma and body dissatisfaction (1). Also, an astute online comment on this paper by Edward Schor at Stanford University reminds us that all screening programmes carry potential for harm, and should be offset by clearly beneficial actions and resources for those who screen positive.
I would add that there must surely be some degree of weight dissatisfaction to motivate the lifestyle efforts needed to achieve weight management - but too much may impair mental health. Hence it is reassuring to see the reduction in concerning weight control behaviors in this trial. However, deeper understanding is needed on the overall impacts on any preventive programme on health and wellbeing.
Reference: 1. Tracy K. Richmond, Idia B. Thurston, Kendrin R. Sonneville. Weight-Focused Public Health InterventionsNo Benefit, Some Harm. JAMA Pediatrics. 2021;175(3):238239.