Randomised controlled trial of primary school based intervention to reduce risk factors for obesity

Abstract Objective: To assess if a school based intervention was effective in reducing risk factors for obesity. Design: Group randomised controlled trial. Setting: 10 primary schools in Leeds. Participants: 634 children aged 7-11 years. Intervention: Teacher training, modification of school meals, and the development of school action plans targeting the curriculum, physical education, tuck shops, and playground activities. Main outcome measures: Body mass index, diet, physical activity, and psychological state. Results: Vegetable consumption by 24 hour recall was higher in children in the intervention group than the control group (weighted mean difference 0.3 portions/day, 95% confidence interval 0.2 to 0.4), representing a difference equivalent to 50% of baseline consumption. Fruit consumption was lower in obese children in the intervention group (−1.0, −1.8 to −0.2) than those in the control group. The three day diary showed higher consumption of high sugar foods (0.8, 0.1 to 1.6)) among overweight children in the intervention group than the control group. Sedentary behaviour was higher in overweight children in the intervention group (0.3, 0.0 to 0.7). Global self worth was higher in obese children in the intervention group (0.3, 0.3 to 0.6). There was no difference in body mass index, other psychological measures, or dieting behaviour between the groups. Focus groups indicated higher levels of self reported behaviour change, understanding, and knowledge among children who had received the intervention. Conclusion: Although it was successful in producing changes at school level, the programme had little effect on children's behaviour other than a modest increase in consumption of vegetables. What is already known on this topic Obesity is increasing among school children and demands preventive strategies Randomised controlled trials of school based primary prevention programmes have all used a prescriptive approach What this study adds Behavioural changes were disappointing with this programme based on the health promoting schools philosophy, despite changes at school level The only positive outcome was a modest increase in vegetable consumption The discrepancy between changes achieved at the individual and school level raises issues regarding the problems inherent in such trials