Success of community interventions for childhood obesity varies depending on the target age group

Stockholm, Sweden: Community-based interventions designed to prevent obesity in children seem to work best in those under the age of five, while there is evidence of some success in primary school children, but very mixed effects in adolescents, a leading expert in the field said today (Tuesday).

In a presentation at the International Congress on Obesity in Stockholm, Professor Boyd Swinburn, chair of population health and director of the World Health Organization Collaborating Centre for Obesity Prevention at Deakin University in Australia, reported findings of an evaluation of the success of three community-based demonstration projects around the Australian city of Geelong. Each targeted a different age group for about three years and included a comparison population that got no intervention. One focused on children under the age of five, another intervened at the primary school age and the third targeted teenagers. The intervention program for teenagers also had similar sister projects in Fiji, Tonga and Auckland, New Zealand. The interventions included a range of strategies to increase healthy eating and physical activity and aimed to build the capacity of the community to continue with them once the project ended.

Comprehensive community-based interventions are in their infancy, Swinburn said. The first generation of demonstration projects included brief intervention periods with implementation limited to schools.

Most of those showed relatively modest, or no, effects. However, more recent studies in the last five years have become increasingly sophisticated, broadening beyond schools to the whole community, to include parents, local government, sports clubs and other settings. Such second-generation studies have been undertaken in a variety of locations around the world, but most have focused on primary school aged children, with few in pre-schoolers or adolescents.

"Our results, together with the evidence from other demonstration projects conducted elsewhere, suggest we should get moving to scale up efforts in the under-5s. There hasn't been that much research in this age group, but what has been done around the world indicates these children seem to be the most susceptible to change," Swinburn said. "For primary school children, the effects seen in studies aren't as strong, but there's enough evidence to say we should roll out what we know. But for adolescents, programmes seem to have an effect for some groups but not others. For Pacific populations, in particular, we saw little impact on weight gain and for those groups, unfortunately, we need to go back to the drawing board."

In Swinburn's study, the best results were seen in the programme that targeted children under five. It involved 12,000 children targeted in multiple settings, such as pre-schools, day care, homes and maternal and child health services. After three years, the prevalence of overweight and obesity among the children in the intervention group was about 3 percentage points lower than that in the comparison group. This programme was also notable for its very small budget for the interventions (AUD100,000 in total) so most of the work was 'in-kind' from the existing personnel and budgets of community organizations.