2.3. Participants
disability
RECRUITMENT
According to the Children Health Management System, the central area of Jiading District contains 38 resident committees, and ~3,500 children aged 0–3 years who are registered with the child-care-management system of the local community health service centers and who receive regular physical examinations. There are two towns in the area, and each town has one health community center (Jiading Town Health Community Center and Juyuan Town Health Community Center, respectively). From January 1 to February 28, 2019, parents who brought their children to the community health service centers to receive physical examinations were asked to participate in this study, and those that agreed were allocated to one of four WeChat groups. Stratified sampling by child age was used for recruitment. In each town, the parents who agreed to participate were randomly allocated to an intervention group or a control group using a random number table. Thus, the following four WeChat groups were consequently created: Jiading invention group and Jiading control group, and Juyuan invention group and Juyuan control group, respectively. The present study analyzed data for the Jiading intervention group and the Jiading control group. The socio-demographic characteristics comparison and the time-series plot of chatting records were shown in The inclusion criteria for parents were as follows: (1) having a child aged 0–3 years; (2) being the main child caregiver (also eligible if other parent was the main child caregiver) who cares child in daily life and spends much time on caring; (3) being a frequent user of WeChat who uses it in daily life and spends much time on it; (4) having the ability of reading and writing; (5) willing to voluntarily provide informed consent; (6) not planning to move residence from March 2019 to December 2020.The exclusion criteria for parents were as follows: (1) providing missing data for children about importance indicators and cannot be filled; (2) not cooperating with community childcare doctors in regard to completing their child's treatment; (3) the presence of a disability among the child or parents; (4) participating (the parents and/or their children) in another study.