The rapid economic growth and lifestyle transition that has recently taken place in Mainland China has coincided with a remarkable rise in the prevalence of overweight and obesity among children. For example, in urban areas of coastal big cities including Nanjing City, in students aged 10–12 years old, the rate of overweight and obesity was 25.5% in boys and 14.3% in girls in 2000 [3, 34]. Thus population-based obesity interventions are urgently needed in China, especially in major cities such as Nanjing. To prevent obesity it is necessary for students to maintain a good balance between energy intake and energy expenditure with sufficient consideration of children’s body growth. This can be achieved by a healthy diet and adequate daily physical activity. Our intervention aims to increase healthy eating, physical activity and to reduce sedentary behaviors among all students allocated to receive the intervention program.
Some of the social environmental factors affecting students’ energy balanced related behaviors (EBRB) in China differ from those in Western societies. For example, Chinese students have a considerably heavier study burden and spend much less time in organized sports and playing outside , this is mainly due to high level of competitiveness in Chinese schools. Generally, students' academic performance is the dominant measure used to assess schools' achievement by both students’ parents/guardians and local educational authorities. Consequently, students’ academic performance is the top priority for school principals and classroom teachers, especially as academic performance is closely linked to their achievement outcomes including financial incentives. In such Chinese social, cultural and economic context, any obesity prevention and other health promotion programs need to make a strong case to win schools’ and parents’ interest, support, and active involvement.
At present, most school-based obesity intervention programs have been conducted in Western countries, and so have limited generalizabiliy to the Chinese context [12–19, 35]. To date very few school-based obesity intervention studies targeting a reduction in obesity/overweight rates among overall students have been conducted in Mainland China [36, 37], a culturally and ethnically different society from Western communities.
This study was specifically designed to develop a feasible and effective population-based intervention program that targeted lifestyle and behavioral factors contributing to excessive weight gain in school children under the current educational context in Mainland China. There were several stages for us to undertake in the development of this study. First, based on previous data on children excess body weight and its associated risk factors in Mainland China [24–27, 34, 38], we realized the urgent need of developing an obesity intervention program tailored for Chinese school students. Second, we identified key environmental, lifestyle and behavior determinants for obesity in Chinese school children. Third, we thoroughly reviewed both English and Chinese literature, and identified potential intervention components. Fourth, we contacted researchers who have designed similar intervention trials. We had fruitful discussions with researchers, especially from the HEALTH-KIDS Study which was conducted in the United States of America . The insights gained from these discussions were very beneficial. Fifth, we consulted responsible/key persons in local educational authorities, school principals and teachers to get their ideas and suggestions on the study. For example, all educational experts consulted believed early intervention against obesity is greatly needed in China, and strongly suggested our study would be better if it was integrated into the current educational system. Sixth, we organized an international research team for this study, including experts from US and Australia. Seventh, taking into account the Chinese educational and social system and the implications from the HEALTH-KIDS study, we developed the study protocol paying particular attention to the feasibility and long-term effect of our study in the current context of Mainland China.
Our intervention program emphasized the need for multilevel interventions, including multiple intervention components that target the classroom curriculum (both healthy dieting and physical activity), school environmental support, family involvement and fun programs/events. We integrated our intervention components into schools’ academic programs, which is critical for such health intervention programs to be acceptable and feasible in China and was really crucial for us to successfully obtain sufficient support from school administrators, teachers, and students and their parents/guardians. We implemented this study with limited impact on the schools’ academic schedule.
In summary, we designed this lifestyle intervention project with due consideration of Chinese cultural and familial tradition, social convention, and current primary education and exam system in China, and the successful experience from the Chicago-based HEALTH-KIDS obesity prevention program. We did our best to gain good support from educational authorities, school administrators, teachers and parents, and to integrate intervention components into schools’ regular academic programs. The findings and experience gained in this study will help guide future school-based childhood obesity prevention programs in China as well as to provide insight for other low- and middle income countries.