Abstract
IMPORTANCE: Excessive screen time is associated with delays in development; however, it is unclear if greater screen time predicts lower performance scores on developmental screening tests or if children with poor developmental performance receive added screen time as a way to modulate challenging behavior. OBJECTIVE: To assess the directional association between screen time and child development in a population of mothers and children. DESIGN, SETTING, AND PARTICIPANTS: This longitudinal cohort study used a 3-wave, cross-lagged panel model in 2441 mothers and children in Calgary, Alberta, Canada, drawn from the All Our Families study. Data were available when children were aged 24, 36, and 60 months. Data were collected between October 20, 2011, and October 6, 2016. Statistical analyses were conducted from July 31 to November 15, 2018. EXPOSURES: Media. MAIN OUTCOMES AND MEASURES: At age 24, 36, and 60 months, children's screen-time behavior (total hours per week) and developmental outcomes (Ages and Stages Questionnaire, Third Edition) were assessed via maternal report. RESULTS: Of the 2441 children included in the analysis, 1227 (50.2%) were boys. A random-intercepts, cross-lagged panel model revealed that higher levels of screen time at 24 and 36 months were significantly associated with poorer performance on developmental screening tests at 36 months (β, -0.06; 95% CI, -0.10 to -0.01) and 60 months (β, -0.08; 95% CI, -0.13 to -0.02), respectively. These within-person (time-varying) associations statistically controlled for between-person (stable) differences. CONCLUSIONS AND RELEVANCE: The results of this study support the directional association between screen time and child development. Recommendations include encouraging family media plans, as well as managing screen time, to offset the potential consequences of excess use.