Public health preventive measures and child health behaviours during COVID-19: a cohort study

Objective: The primary objective was to determine the association between public health preventive measures and children’s outdoor time, sleep duration, and screen time during COVID-19. Methods: A cohort study using repeated measures of exposures and outcomes was conducted in healthy children (0 to 10 years) through The Applied Research Group for Kids (TARGet Kids!) COVID-19 Study of Children and Families in Toronto, Canada, between April 14 and July 15, 2020. Parents were asked to complete questionnaires about adherence to public health measures and children’s health behaviours. The primary exposure was the average number of days that children practiced public health preventive measures per week. The three outcomes were children’s outdoor time, total screen time, and sleep duration during COVID-19. Linear mixed-effects models were fitted using repeated measures of primary exposure and outcomes. Results: This study included 554 observations from 265 children. The mean age of participants was 5.5 years, 47.5% were female and 71.6% had mothers of European ethnicity. Public health preventive measures were associated with shorter outdoor time (−17.2; 95% CI −22.07, −12.40; p< 0.001) and longer total screen time (11.3; 95% CI 3.88, 18.79; p= 0.003) during COVID-19. The association with outdoor time was stronger in younger children (<5 years), and the associations with total screen time were stronger in females and in older children (≥5 years). Conclusion: Public health preventive measures during COVID-19 were associated with a negative impact on the health behaviours of Canadian children living in a large metropolitan area.