Association between television in bedroom and adiposity throughout adolescence

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.

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.

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.

These results suggest the importance of keeping TV out of an adolescent's bedroom from an obesity prevention perspective but show gender differences.