School environment and policies, child eating behavior and overweight/obesity in urban China: the childhood obesity study in China megacities.

OBJECTIVES: Childhood obesity is rising rapidly in China, especially in urban areas. Knowledge about how school environment and policies (SEPs) may have contributed to the epidemic remains limited. We examined SEP and their associations with students' eating behaviors and overweight/obesity in urban China.

METHODS: Data were collected from 1648 students (plus their parents and schools) in 16 primary and middle schools (4 schools per city) in four megacities across China: Beijing, Shanghai, Nanjing and Xi'an. We examined nutrition-related SEP such as unhealthy food restriction, healthy food promotion, price control and nutrition guideline in school cafeterias (SCs), campus food stores (CFS), school vicinity food stalls (SVFS); SEP on physical activity, physical education (PE) and physical examination. Cluster robust regression models were fit to assess associations of SEP with child eating behaviors and overweight/obesity (defined based on body mass index, from measured weight and height).

RESULTS: All 16 schools had regular PE classes and annual physical examination. Most schools (n=12; 75%) had food policies in SC; few had policies on CFS (n=1; 6.25%) or SVFS (n=4; 25%). Local governments had a major role in regulating food prices, setting nutrition guidelines and regulating SVFS. Policies on CFS and SVFS were associated with less frequent intake of sugary beverage (odds ratio (OR)=0.54 (0.47-0.61); OR=0.70 (0.61-0.80)), snack (OR=0.84 (0.74-0.95); OR=0.78 (0.67-0.92)) and fast food (OR=0.58 (0.42-0.81); OR=0.56 (0.39-0.80)). The associations were stronger for boys. Policies on SC, CFS and SVFS were associated with lower likelihood for overweight/obesity (OR=0.60 (0.46-0.79); OR=0.74 (0.62-0.90); OR=0.51 (0.35-0.73)) and central obesity (OR=0.79 (0.70-0.89); OR=0.67 (0.48-0.92); OR=0.63 (0.48-0.84)) in boys. Policies on SC were associated with lower overweight/obesity odds (OR=0.48 (0.28-0.82)) for girls.

CONCLUSIONS: SEP are heterogeneous in the four Chinese megacities, high-income areas. They affect child unhealthy eating and overweight/obesity, and are critical for fighting childhood obesity in China.