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).

The authors have declared no competing interest.

https://fundingawards.nihr.ac.uk/award/NIHR131572

This study was funded by National Institute for Health and Care Research (NIHR).

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