Objective: To estimate the influence of early childhood television exposure on fourth-grade academic, psychosocial, and lifestyle characteristics.
Design: Prospective longitudinal study.
Setting: Institut de la Statistique du Québec, Québec, Canada.
Participants: A total of 1314 (of 2120) children. Main Exposure Parent-reported data on weekly hours of television exposure at 29 and 53 months of age. We conducted a series of ordinary least-squares regressions in which children's academic, psychosocial, and lifestyle characteristics are linearly regressed on early and preschool television exposure.
Outcome measures: Parent and teacher reports of academic, psychosocial, and health behaviors and body mass index measurements (calculated as weight in kilograms divided by height in meters squared) at 10 years of age.
Results: Adjusting for preexisting individual and family factors, every additional hour of television exposure at 29 months corresponded to 7% and 6% unit decreases in classroom engagement (95% confidence interval [CI], -0.02 to -0.004) and math achievement (95% CI, -0.03 to 0.01), respectively; 10% unit increases in victimization by classmates (95% CI, 0.01 to 0.05); 13% unit decreases in time spent doing weekend physical activity (95% CI, 0.81 to 2.25); 9% unit decreases in activities involving physical effort (95% CI, -0.04 to 0.00); higher consumption scores for soft drinks and snacks by 9% and 10% (95% CI, 0.00 to 0.04 and 95% CI, 0.00 to 0.02), respectively; and 5% unit increases in body mass index (95% CI, 0.01 to 0.05). Preschool increments in exposure also made a unique contribution to developmental risk.
Conclusions: The long-term risks associated with higher levels of early exposure may chart developmental pathways toward unhealthy dispositions in adolescence. A population-level understanding of such risks remains essential for promoting child development.