Objective  To analyze the variation in screen time before and after the outbreak of coronavirus disease 2019 (COVID-19) and the correlation between the variation and behavior problems among preschool children.

  Methods  Using stratified cluster sampling, we recruited 8 882 kindergarten children aged 3 – 6 years in 4 urban districts, 3 development zones, 3 counties and one county-level prefecture in Hefei municipality of Anhui province and conducted an online voluntary survey among the children′s parents during May 2020. A self-designed questionnaire and Conners′ Parent Symptom Questionnaire (PSQ) were adopted to collect relevant information. Multivariate logistic regression analysis was performed to explore the correlation between the variation in screen time and behavior problems among the preschool children.

  Results   Of the 8 844 children (4 770 boys and 4 074 girls, mean age = 4.43 ± 0.98 years) with valid information, 54.82% (4 844) were reported with the daily screen time of ≤ one hour before and during the COVID-19 epidemic, 22.17% (1 961) with the time of ≥ one hour before and during the COVID-19 epidemic, 21.35% (1 888) with the time of ≤ one hour before but > one hour during the COVID-19 epidemic, and only 1.66% (147) with the time of > one hour before but ≤ one hour during the epidemic period. The results of logistic regression analysis demonstrated that compared with those with a daily screen time of ≤ one hour before and during the period of epidemic, the children with following daily screen time were at an increased risk of having behavior problems: > one hour before and during the COVID-19 epidemic (odds ratio OR = 1.78, 95% confidence interval 95% CI = 1.55 – 2.04), ≤ one hour before but ≥ one hour during the epidemic (OR = 1.63, 95% CI = 1.42 – 1.88), > one hour before but ≤ one hour during the epidemic (OR = 1.57, 95% CI = 1.03 – 2.38). In comparison to those with the daily screen time of ≤ one hour before and during the COVID-19 epidemic, the children with the time of ≥ one hour before and during the COVID-19 epidemic and the time of ≤ one hour before but > one hour during the epidemic were at a significantly increased risk of behavior problems including bad conduct, learning difficulty, impulsion-hyperactivity, anxiety, and hyperactivity (all P < 0.05).

  Conclusion  Some preschool children had an increased daily screen time during the period of COVID-19 epidemic and the variation in the daily screen time may relate to the incidence of behavior problems in the children.