Background: Community based interventions (CBIs) show promise in preventing obesity in children and adolescents, however there is limited published synthesis of behavioural outcomes (e.g. physical activity, diet) across multiple CBIs. The evidence of the cost-effectiveness of CBIs is also inconclusive, and most published economic evaluations only incorporate a narrow range of weight-related outcomes. Ignoring potential wider benefits, such as improved health behaviours, may result in underestimation of the health and economic impact of CBIs.
This study aimed to investigate the impact of six Australian CBIs on children’s weight and weight-related behaviours, and quantify the health and economic benefits of this approach to obesity prevention.
Methods: Individual level meta-analyses estimated the effect of each CBI on change in weight (Body Mass Index (BMI) z-score), and weight-related behaviours (physical activity, sedentary behaviour, fruit and vegetable intake). Multi-level linear models estimated the intervention effect on zBMI and on weight-related behaviours, adjusted for individual and area-level factors and clustering at school and individual levels. Where results indicated a significant impact of the intervention on a weight or behavioural outcome, further economic modelling was conducted to estimate the potential health benefits and healthcare cost-savings of these interventions.
Results: Six Australians trials conducted between 2003 and 2022, with students aged 4-18 years were included, with a total of 13,528 baseline and 10,342 endpoint observations. Preliminary results indicate students in intervention communities increased physical activity by 5.8 mins/day (95% CI 3.1, 8.5) more than control communities, and had less weight gain compared to control communities (zBMI difference -0.03, 95% CI-0.06, -0.001). Economic modelling is underway and results will be presented at the conference.
Conclusion: CBIs can have positive effects on children and adolescents’ behaviours and weight. By combining individual participant data from six Australian trials, this analysis provides robust estimates of health and economic benefits of CBIs.