Preschooler Screen Time During the Pandemic Is Prospectively Associated With Lower Achievement of Developmental Milestones.

Objective: The aim of this study was to assess the developmental risks associated with total screen time, and specifically newer mobile devices, in the context of the pandemic.

Methods: This study uses parent-reported data from a prospective cohort of Canadian preschool-age children. The exposure variable is child daily screen time measured at the age of 3.