Large reductions in child overweight and obesity in intervention and comparison communities 3 years after a community project

What is already known about this subject: Childhood obesity has been increasing over decades and scalable, population-wide solutions are urgently needed to reverse this trend. Evidence is emerging that community-based approaches can reduce unhealthy weight gain in children. In some countries, such as Australia, the prevalence of childhood obesity appears to be flattening, suggesting that some population-wide changes may be underway.

What this study adds: A community-based intervention project for obesity prevention in a rural town appears to have increasing effects 3 years after the end of the project, substantially reducing overweight and obesity by 6% points in new cohorts of children, 6 years after the original baseline. An apparent and unanticipated 'spillover' of effects into the surrounding region appeared to have occurred with 10%-point reductions in childhood overweight and obesity over the same time period. A 'viral-like' spread of obesity prevention efforts may be becoming possible and an increase in endogenous community activities appears to be surprisingly successful in reducing childhood obesity prevalence.

Background: The long-term evaluations of community-based childhood obesity prevention interventions are needed to determine their sustainability and scalability.

Objectives: To measure the impacts of the successful Be Active Eat Well (BAEW) programme in Victoria, Australia (2003-2006), 3 years after the programme finished (2009).

Methods: A serial cross-sectional study of children in six intervention and 10 comparison primary schools in 2003 (n = 1674, response rate 47%) and 2009 (n = 1281, response rate 37%). Height, weight, lunch box audits, self-reported behaviours and economic investment in obesity prevention were measured.

Results: Compared with 2003, the 2009 prevalence of overweight/obesity (World Health Organization criteria) was significantly lower (P < 0.001) in both intervention (39.2% vs. 32.8%) and comparison (39.6% vs. 29.1%) areas, as was the mean standardized body mass index (0.79 vs. 0.65, 0.77 vs. 0.57, respectively) with no significant differences between areas. Some behaviours improved and a few deteriorated with any group differences favouring the comparison area. In 2009, the investment in obesity prevention in intervention schools was about 30 000 Australian dollars (AUD) per school per year, less than half the amount during BAEW. By contrast, the comparison schools increased from a very low base to over 66 000 AUD per school per year in 2009.

Conclusions: The 8%-point reduction in overweight/obesity in both areas over 6 years from baseline to 3 years post-intervention was substantial. While the benefits of BAEW increased in the intervention community in the long term, the surrounding communities appeared to have more than caught up in programme investments and health gains, suggesting a possible 'viral spread' of obesity prevention actions across the wider region.