Internet addiction and child physical and mental health: Evidence from panel dataset in China

•This study was designed to help improve understanding of the negative effects of Internet addiction on child health.•We use DID and PSM-DID methods to solve the possible endogeneity problems effectively.•Internet addiction impairs child physical and mental health by reducing their sleep and exercise time.•Internet addiction has a significant correlation with the mental health of left-behind children, but not children living with both parents.