Viewing as little as 1 hour of TV daily is associated with higher change in BMI between kindergarten and first grade.

Abstract

Evaluate associations between TV viewing and weight status in children from kindergarten to first grade. Linear and logistic regression was used to evaluate associations of TV-viewing time on BMI-z-score cross-sectionally at kindergarten and first grade and longitudinally in between, among a nationally representative sample of 14,645 children from the Early Childhood Longitudinal Study-Kindergarten Cohort 2011. All analyses were adjusted for sex, race/ethnicity, parental education, and household income. Weekday TV-viewing time was correlated with BMI-z-score (P < 0.01) at kindergarten and first grade and with change in BMI-z-score in between (P < 0.05). Compared with children watching <1 h of TV daily, children watching ≥1 h in kindergarten and first grade had a greater odds of overweight (1.50-1.60) and obesity (1.58-1.73). Children watching 1-<2 h and ≥2 h daily had higher BMI-z-scores (P < 0.0001) and less favorable changes in BMI-z-score between time points (P < 0.05). Children who were not overweight or obese in kindergarten and watched ≥1 h of TV had a greater odds of becoming overweight (1.39) and obese (1.86) between evaluations. Children watching as little as 1-<2 h of TV daily were more likely to become overweight and obese over time. Physicians should encourage families to restrict TV-viewing time to reduce weight gain.