The Christchurch Obesity Prevention Programme in Schools (CHOPPS).

The prevention of childhood obesity has become a national priority and previous school-based obesity prevention interventions have shown limited success. The consumption of sugar-sweetened drinks is a known causative factor of childhood obesity. A pilot study confirmed that the prevalence of childhood obesity was cause for concern in the local area. This pilot study found that the children were frequent consumers of carbonated drinks, a known causative factor for obesity. The aim of this study was to determine if a school based education programme, specifically focused on discouraging the consumption of carbonated drinks could reduce the prevalence of childhood obesity.

The study design was a cluster randomised controlled trial, including 644 children from 6 schools, in 29 classes. Anthropometric measures of height and weight and waist circumference were obtained. Body Mass Index (weight (kg)/(height (m) 2)) was converted to standard deviation scores (or z-scores) and to centile values using the 1990 UK growth reference curves. Measurements were taken at baseline and 12 months after completion of the intervention. 3-day drinks diaries were completed at baseline and at 12 months. The intervention was conducted over one school year, including 4 sessions of focused education promoting a healthy diet and discouraging the consumption of carbonated drinks. Further longitudinal measurements were taken 3 years post baseline.

At 12 months the consumption of carbonated drinks decreased in the intervention group by 0.6 glasses/3 days and increased in the control group by 0.2 glasses in the control group (mean difference 0.7, 95% CI 0.1 10 1.3). The percentage of overweight children increased in the control group by 7.5% but decreased in the intervention group by 0.2% (mean difference 7.7%, 95% CI 2.2%-13.1%). The prevalence of overweight increased in both the intervention and control group at 3 years and the significance difference seen at 12 months was no longer evident (risk difference 4.6%, 95% CI -4.3%, 13.5%).

The initial results at 12 months suggested that this specific intervention produced a modest reduction in the number of carbonated drinks consumed and there was a reduction in the number of overweight and obese children in the control group. The longitudinal results 2 years following the intervention suggest that the difference in prevalence of overweight seen at 12 months was not sustained.