Cross-sectional and longitudinal associations between TV viewing and girls' body mass index, overweight status, and percentage of body fat

Objective To assess cross-sectional and longitudinal relations between television (TV) viewing and girls' body mass index (BMI), weight status, and percentage of body fat. Study design Participants included 169 girls who were measured at ages 7, 9, and 11 years. Height and weight were measured and used to calculate girls' BMI and to classify their weight status. Girls' percentage of body fat was assessed with the use of dual-energy x-ray absorptiometry. Mothers reported the hours per day that girls watched TV on a typical day. Results No significant cross-sectional associations were identified. Results from longitudinal analyses showed that in comparison to girls who never exceeded the American Academy of Pediatrics TV viewing recommendations (ie, watched <= 2 hours of TV per day), girls who exceeded recommendations at ages 7, 9, and 11 years were 13.2 times more likely be overweight at age 11, were 4.7 times more likely to become overweight between ages 7 and 11, had significantly higher BMI and percentage body fat at age 11, and exhibited significantly greater increases in BMI between ages 7 and 11. Conclusions interventions that target reductions in TV viewing among 7- to 11-year-old girls may help to reduce their risk of weight gain during late childhood.