Objective: To test the independent effect of television exposure in preschool-aged children on overweight risk.
Design: Cross-sectional and longitudinal analysis of the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development.
Setting: Ten US sites.
Participants: One thousand sixteen children selected via conditional random sampling.
Main exposure: Being awake in the room with the television on for 2 hours or more per day, by maternal report at age 36 months.
Main outcome measures: Child overweight (body mass index [calculated as weight in kilograms divided by the square of height in meters] > or =95th percentile) calculated from measured anthropometrics at ages 36 and 54 months. Covariates tested included child sex and race; maternal marital status, education, age, and depressive symptoms; income-needs ratio, child behavior problems; Home Observation for Measurement of the Environment total score; hours per week in nonparental care; and proportion of television exposure that was educational.
Results: At age 36 months, 5.8% of children were overweight; at age 54 months, 10.0% were overweight. Exposure to 2 or more hours of television per day was associated with an increased risk of overweight at both age 36 months (odds ratio, 2.92; 95% confidence interval, 1.36-6.24) and age 54 months (odds ratio, 1.71; 95% confidence interval, 1.03-2.83) in unadjusted analyses. Only maternal age altered the concurrent relationship, and the effect of television remained significant (odds ratio, 2.61; 95% confidence interval, 1.21-5.62). Television exposure at age 36 months was no longer a significant predictor of overweight at age 54 months when controlling for covariates.
Conclusion: Excessive television exposure is a risk factor for overweight in preschoolers independent of a number of potential confounders associated with the quality of the home environment.