Do the Effects of Interventions Aimed at the Prevention of Childhood Obesity Reduce Inequities? A Re-Analysis of Randomized Trial Data from Two Cochrane Reviews

Background Public health attempts to prevent obesity in children and young people should aim to minimize health inequalities. We aimed to assess whether there were differences in the effectiveness of the interventions included in two Cochrane reviews according to the eight PROGRESS inequity factors. Methods We collected data on change in BMI (standardized or unstandardized), subgrouped by baseline measures of PROGRESS factors, for intervention and control groups, from trial authors. We calculated the intervention effect per subgroup (mean difference), then contrasted these to estimate interactions between intervention and the baseline factors. We combined interaction estimates for each factor across trials using standard procedures for meta-analysis. Findings Our analysis of interventions from 81 trials found no substantial differences in effectiveness for different subgroups in most scenarios. However, in the younger age group (5-11 years), the effect of interventions on standardized BMI appeared to be higher in boys. Interpretation The Cochrane reviews found that interventions promoting physical activity (only) have a beneficial effect on BMI (compared with a control group) for children and young people aged 5-18 years, as well as interventions promoting physical activity alongside healthy eating for 5-11 year olds. Although these beneficial effects were small, when delivered at scale, they may have the potential to contribute meaningfully to reducing the prevalence of childhood obesity. Our findings suggest that those responsible for public health can promote these beneficial interventions without major concerns about increasing inequalities. Because many of the interventions studied, including school-based interventions, provide building blocks of whole systems approaches , the findings are relevant to policy and practice. Funding National Institute for Health and Care Research (NIHR). ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Protocols ### Funding Statement This study was funded by National Institute for Health and Care Research (NIHR). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors