Sun X, Zhao B, Liu J, et al. - Researchers undertook this open cohort study of students from five major cities (Beijing, Shanghai, Xi'an, Nanjing, and Chengdu) across China, to assess their physical activity and sedentary behaviours during 2015 to 2017 as well as links of these with children's weight status and relevant gender disparities. During 2015 to 2017, high rates of obesity as well as central obesity were evident in these children. More chance of being obese was noted in those who walked <5 minutes on their average daily walk to school vs those who spent ≥15 minutes on walking to school. According to gender stratification, only girls were found to have this higher risk. The identified risk factors for developing obesity in urban Chinese children were: more screen time and less walking time. The links differed by gender.