1. Introduction
obesity, health-risk behaviors, adiposity, overweight or obesity, sedentary behaviors
OBESITY, CHILDHOOD OBESITY, ADIPOSITY
Some studies have found associations between the peer network and childhood obesity. The present study aimed to analyze the association of the peer network with obesity-related cognition, behaviors and adiposity indicators, and explore whether peer network influences the effect of a childhood-obesity intervention. Based on DECIDE-Children, 1392 children’s friendship nominations within the class were collected and peer network indicators including the network size, network density, and in- and out-degree centrality were calculated. The linear mixed model was used to analyze the association between peer network indicators and children’s cognition, behaviors and adiposity indicators (body mass index (BMI), BMI z score, the prevalence of overweight and obesity). Children with a higher in-degree centrality had 34.4% (95%CI: 17.4% to 48.1%) lower risk of overweight or obesity. The baseline degree centrality was inversely associated with the BMI and BMI z score at the end of the trial. For each unit increase in in-degree centrality at baseline, the BMI at the end of the trial decreased by 0.047 (95%CI: 0.015 to 0.080), and the BMI z score decreased by 0.015 (95%CI: 0.003 to 0.028). Children’s popularity reflected by centrality in their peer network was associated with cognition, behaviors, and adiposity indicators. Future childhood-obesity intervention research could pay more attention to socially inactive children.Individuals are embedded in thick networks of social relationships and interactions. Social networks represent relatively stable systems composed of relationships among individuals (e.g., friendship), and reflect an individual’s social environment [Traditional epidemiological research has mainly focused on health-risk behaviors of individuals in a group, while the network theory suggests that individuals’ health and health-related behaviors are affected by the embedded social network [To date, some observational evidence has supported the idea that the social environment is one of major determinants of health and health-related behaviors, and highlighted the role of the peer network in the children’s health. Children’s activeness or popularity in a peer network might affect their health-related behaviors, such as sleep, physical activity and sedentary behaviors [Based on a multifaceted intervention program for preventing obesity in primary school children in China, the present study aimed to analyze the association of the peer network with obesity-related cognition, behaviors and adiposity indicators, and explore whether centrality in a peer network influences the effect of a childhood-obesity intervention (i.e., adiposity indicators at the end of the trial), in order to provide scientific evidence for the future childhood-obesity intervention strategies.