The impact of social network on childhood obesity is a critical yet understudied area particularly in international settings. This study examined social network effects on energy balance behaviors and weight status of Chinese children.


The Childhood Obesity Study in China Mega-cities (COCM study) 2016 data were used. Data were collected in five major cities across China, including Beijing, Shanghai, Nanjing, Xi’an, and Chengdu. IOTF standard was used to estimate BMI-z scores. Ego network analysis was conducted and mixed effect models were fit to examine the ego-alter relationships in terms of dietary intake, physical activity, and weight status.


We identified 273 children who were egos and 1455 children who were alters in social networks. The average net size is 5.33 with an average density of 0.63.Our mixed effect model estimates suggested that a child’s BMI-z score was positively associated with his/her friends’ BMI-z score (β=0.33, P<0.001). Additionally, a child’s fast food consumption and outdoor physical activity were also associated with his/her friends’ fast food consumption (β=0.33 times/week, P<0.001) and outdoor physical activity (0.25 times/week, P<0.001). After controlling for shared food and environment effects, the associations remained the same for outdoor physical activity, with a slight decrease of the mixed effect estimates for BMI_z (β=0.31, P=0.02) and fast food consumption (β = 0.27 times/week, P=0.01).


The social networks influences on energy balance behaviors and weight status were evident among Chinese children. Social network based interventions are potentially effective in curbing the rise of childhood obesity in China.