Review of impacts of using body mass index as a screening tool in school children: A scoping review.

Body mass index (BMI) is used to screen for under- or overweight. However, it is unknown whether BMI-screening in school children reduces the incidence of overweight and obesity. We aimed to summarise the knowledge on positive and negative consequences on BMI and weight-related perceptions and behaviours of BMI-screening followed by an intervention to prevent and/or address obesity. We performed a systematic literature search, April 2023, using the PubMed, ScienceDirect and Google Scholar databases. We included randomised controlled trials and observational studies, including children aged 6 to 18 years and examining BMI-screening in a school setting. The primary outcome measures were BMI and weight status. Secondary outcome measures were weight-related perceptions and behaviours. Three studies met the inclusion criteria; two randomised controlled trials and one observational study. All studies used BMI-screening followed by sending report cards to the parents. None of the studies found a change in BMI z-scores in school children. Screening could cause transitory body-dissatisfaction and increase peer weight talk, yet potentially reduce problematic weight behaviours like skipping meals or excessive dieting. Reporting BMI to parents may influence their perception of their children's weight status, but does not change behaviour. The sparse evidence available suggested that BMI screening followed by sending report cards to parents does not change BMI z-scores among children in primary, middle and high school. Studies using appropriate evidence-based weight management interventions as a follow-up are lacking. Such studies may improve future prevention, detection and treatment of weight-related issues.