Some observational studies have found an association between television viewing and child and adolescent adiposity. To assess the effects of reducing television, videotape, and video game use on changes in adiposity, physical activity, and dietary intake. Randomized controlled school-based trial conducted from September 1996 to April 1997. Two sociodemographically and scholastically matched public elementary schools in San Jose, Calif. Of 198 third- and fourth-grade students, who were given parental consent to participate, 192 students (mean age, 8.9 years) completed the study. Children in 1 elementary school received an 18-lesson, 6-month classroom curriculum to reduce television, videotape, and video game use. Changes in measures of height, weight, triceps skinfold thickness, waist and hip circumferences, and cardiorespiratory fitness; self-reported media use, physical activity, and dietary behaviors; and parental report of child and family behaviors. The primary outcome measure was body mass index, calculated as weight in kilograms divided by the square of height in meters. Compared with controls, children in the intervention group had statistically significant relative decreases in body mass index (intervention vs control change: 18.38 to 18.67 kg/m2 vs 18.10 to 18.81 kg/m2, respectively; adjusted difference -0.45 kg/m2 [95% confidence interval [CI], -0.73 to -0.17]; P = .002), triceps skinfold thickness (intervention vs control change: 14.55 to 15.47 mm vs 13.97 to 16.46 mm, respectively; adjusted difference, -1.47 mm [95% CI, -2.41 to -0.54]; P=.002), waist circumference (intervention vs control change: 60.48 to 63.57 cm vs 59.51 to 64.73 cm, respectively; adjusted difference, -2.30 cm [95% CI, -3.27 to -1.33]; P<.001), and waist-to-hip ratio (intervention vs control change: 0.83 to 0.83 vs 0.82 to 0.84, respectively; adjusted difference, -0.02 [95% CI, -0.03 to -0.01]; P<.001). Relative to controls, intervention group changes were accompanied by statistically significant decreases in children's reported television viewing and meals eaten in front of the television. There were no statistically significant differences between groups for changes in high-fat food intake, moderate-to-vigorous physical activity, and cardiorespiratory fitness. Reducing television, videotape, and video game use may be a promising, population-based approach to prevent childhood obesity.
