Background
Obesity affects children even before they start school, with 1 in 5 Australian children having overweight or obesity at 5 years of age. Early childhood is a period when many behaviours that can contribute to the development of obesity – such as poor eating habits and physical inactivity – are established. These can then track into later childhood and contribute to the problem of obesity.
Interventions that support families to set up healthy habits within the first 2 years of life are more likely to have sustained effects on health. A number of interventions have been tested around the world but the complexity of these interventions limits their translation into policy and practice.
Compexity of Interventions
Early interventions to prevent childhood obesity are usually extensive and complex, cover multiple lifestyle behaviours, and use a range of strategies.
Currently, there is a gap in understanding which parts of early interventions are effective in reducing childhood obesity, and whether certain components are particularly effective for key population groups.
TOPCHILD Aims
The aims of TOPCHILD are:
To deconstruct childhood obesity interventions into their components (i.e. delivery features and behaviour change techniques) using a systematic, internationally recognised framework
To assess each discrete intervention component, establishing their relative impact on child obesity outcomes
To assess which intervention components are particularly effective for specific populations (e.g. by socioeconomic position)
No individual trial alone can answer these questions, hence we are establishing the TOPCHILD Collaboration to bring together planned, ongoing and completed trials from around the world.
Innovative Methods
Project 1: Individual participant data meta-analysis. This is the gold standard for combining trial data, providing greater power for estimation of treatment effects of rarer outcomes. It also enables reliable subgroup analyses.
Results under review, available mid-2025
Project 2: Interventions will be deconstructed into their components, including target behaviours, delivery features and behaviour change techniques (BCTs), These components will be coded into a data set and merged with the complete set of individual participant data created in Part 1.
Results available online: Behavioural components and delivery features of early childhood obesity prevention interventions: intervention coding of studies in the TOPCHILD Collaboration systematic review
Project 3: This project will combine datasets from projects 1 and 2 to evaluate whether the number or combination of intervention features (e.g. target behaviours, or BCTs) make a difference to effectiveness. A small set of directional hypotheses will guide subgroup analyses to identify any consistent patterns or confirm a lack of effect.
Results expected 2026