نبذة مختصرة : Background In countries undergoing rapid economic transition such as China, rates of increase in childhood obesity exceed that in the West. However, prevention trials in these countries are inadequate in both quantity and methodological quality. In high-income countries, recent reviews have demonstrated that school-based prevention interventions are moderately effective but have some methodological limitations. To address these issues, this study evaluated clinical- and cost- effectiveness of the Chinese Primary School Children Physical Activity and Dietary Behaviour Changes Intervention (CHIRPY DRAGON) developed using the United Kingdom Medical Research Council complex intervention framework to prevent obesity in Chinese primary-school–aged children. Methods and findings In this cluster-randomised controlled trial, we recruited 40 state-funded primary schools from urban districts of Guangzhou, China. A total of 1,641 year-one children with parent/guardian consent took part in baseline assessments prior to stratified randomisation of schools (intervention arm, 20 schools, n = 832, mean age = 6.15 years, 55.6% boys; control arm n = 809, mean age = 6.14 years, 53.3% boys). The 12-month intervention programme included 4 school- and family-based components delivered by 5 dedicated project staff. We promoted physical activity and healthy eating behaviours through educational and practical workshops, family activities, and supporting the school to improve physical activity and food provision. The primary outcome, assessed blind to allocation, was between-arm difference in body mass index (BMI) z score at completion of the intervention. A range of prespecified, secondary anthropometric, behavioural, and psychosocial outcomes were also measured. We estimated cost effectiveness based on quality-adjusted life years (QALYs), taking a public sector perspective. Attrition was low with 55 children lost to follow up (3.4%) and no school dropout. Implementation adherence was high. Using intention to treat analysis, the mean difference (MD) in BMI z scores (intervention − control) was −0.13 (−0.26 to 0.00, p = 0.048), with the effect being greater in girls (MD = −0.18, −0.32 to −0.05, p = 0.007, p for interaction = 0.015) and in children with overweight or obesity at baseline (MD = −0.49, −0.73 to −0.25, p < 0.001, p for interaction < 0.001). Significant beneficial intervention effects were also observed on consumption of fruit and vegetables, sugar-sweetened beverages and unhealthy snacks, screen-based sedentary behaviour, and physical activity in the intervention group. Cost effectiveness was estimated at £1,760 per QALY, with the probability of the intervention being cost effective compared with usual care being at least 95% at a willingness to pay threshold of £20,000 to 30,000 per QALY. There was no evidence of adverse effects or harms. The main limitations of this study were the use of dietary assessment tools not yet validated for Chinese children and the use of the UK value set to estimate QALYS. Conclusions This school- and family-based obesity prevention programme was effective and highly cost effective in reducing BMI z scores in primary-school–aged children in China. Future research should identify strategies to enhance beneficial effects among boys and investigate the transferability of the intervention to other provinces in China and countries that share the same language and cultures. Trial registration ISRCTN Identifier ISRCTN11867516.
Bai Li and colleagues reveal a healthy eating and activity intervention in Chinese children that reduces obesity
Author summary Why was this study done? In low- and middle-income countries (LMIC) where childhood obesity is increasing rapidly, there is a lack of rigorous development and evaluation of prevention interventions. Previous childhood obesity prevention trials conducted in China have not provided robust, high-quality evidence of effective interventions. Without effective prevention programs, China is estimated to have 50 million children with overweight or obesity by 2030. What did the researchers do and find? Guided by the United Kingdom Medical Research Council’s complex intervention framework, we developed a school- and family-based intervention (the Chinese Primary School Children Physical Activity and Dietary Behaviour Changes Intervention [CHIRPY DRAGON] programme) for preventing obesity in urban, primary-school–aged children in China. A total of 40 primary schools (1,461 children aged 6 years) were recruited from Guangzhou, China. The children took part in weight status and behavioural assessments before their schools were randomly divided into 2 groups. One group of schools received a package of activities designed to increase healthy eating and physical activity (the CHIRPY DRAGON program) over 12 months, and the other group of schools continued with their usual activities. After 12 months, all children taking part were assessed again, and these measures were compared across the 2 school groups. We also collected and analysed comprehensive data on the costs of the CHIRPY DRAGON programme and how it was implemented. We found that the CHIRPY DRAGON programme was mainly delivered as planned. Children, particularly girls, in the group of schools receiving the program had healthier weight status, dietary intake, and physical activity levels at the end of the 12-month period compared with children in the schools not receiving the programme. The programme was also good value for money. What do these findings mean? This school- and family-based programme may be an effective and cost-effective intervention for the prevention of obesity in children in urban China. Future research should identify strategies to enhance beneficial effects of the programme among boys. It is not yet determined whether this intervention programme can be successfully transferred to other contexts, but it may be effective in other locations that share similar characteristics to urban China.
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