Physical Activity, Sedentary Time, And Diet As Mediators Of The Association Between Tv Time And Bmi In Youth

Purpose:This study examined dietary indicators, sedentary time, and physical activity as potential mediators of the association between TV time and BMIz in youth.Design:Cross-sectional study in 2 independent samples of youth.Setting:Data collection occurred by mail and telephone for adolescents and either at home or in medical settings for children.Sample:928 youth ages 12-16 and 756 youth ages 6-12 and a parent.Measures:TV time, snacking/eating while watching TV, and a 3-day dietary recall were assessed via child/parent report. Physical activity and sedentary time were assessed by accelerometer wear.Analysis:Direct and indirect associations (through 8 diet and activity variables) of TV time with BMIz were tested in boys and girls in each sample.Results:TV time had a positive association with BMIz in 6-12 year old boys and girls. Direct associations emerged between TV time and the diet/activity variables, and between diet/activity variables and BMIz. Snacking/eating while watching TV had a significant positive association with BMIz in younger boys and mediated the association between TV time and BMIz (beta = .06, p = .019; 25% attenuation).Conclusions:Snacking/eating while watching TV may be a possible reason TV time is consistently associated with obesity in youth. Targeting reductions in TV time and associated snacking could improve health impacts.