Association between television in bedroom and adiposity throughout adolescence.

OBJECTIVE: The objective was to determine if having a television (TV) in the bedroom is associated with physical activity (PA), TV/video viewing, and adiposity throughout adolescence. RESEARCH METHODS AND PROCEDURES: Longitudinal data (September 2002 through June 2005) were analyzed of 379 initially 12-year-old French adolescents participating as controls in the Intervention Centered on Adolescents' Physical activity and Sedentary behavior (ICAPS). Presence of a TV set in the bedroom (TV(bedroom)) and leisure activities were obtained by questionnaire. There was annual assessment of BMI, waist circumference, and body fat by bioimpedance.
RESULTS: In boys but not girls, baseline TV(bedroom) was associated with higher TV/video viewing over time [odds ratio (OR) of high TV/video = 1.87; 95% confidence interval, 1.2 to 2.8] and less no-sport club participation (OR = 0.59; 95% confidence interval, 0.35 to 1.0). Both boys and girls with baseline TV(bedroom) had lower reading time (p < 0.0001 in boys; p = 0.04 in girls), while PA did not differ according to TV(bedroom) for boys or for girls. For boys only, baseline TV(bedroom) was associated with higher BMI (mean BMI over time 20.5 +/- 0.5 vs. 19.0 +/- 0.5 kg/m(2); p = 0.001), waist circumference (70.9 +/- 0.9 vs. 67.2 +/- 0.8 cm; p < 0.001), and body fat (15.9 +/- 0.9% vs. 13.5 +/- 0.9%; p < 0.001), without interaction with time. These relationships remained significant after adjustment for socioeconomic status. TV/video viewing explained 26%, 42%, and 36% of the relationships of TV(bedroom) with BMI, waist circumference, and body fat, respectively, while addition of other leisure activities in the models only marginally reduced the effects. DISCUSSION: These results suggest the importance of keeping TV out of an adolescent's bedroom from an obesity prevention perspective but show gender differences.