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 ( = .06, = .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.