ABSTRACT
BACKGROUND: Recent technologies have changed screen time. TV can be viewed anywhere, anytime. Content can be collected via digital recorders and online streaming and viewed on smartphones. Video games are no longer strictly sedentary. OBJECTIVES: We sought to assess the unknown relations between new modes of TV viewing - recorded, online, downloaded and on hand-held devices - and active video games with body mass index (BMI). METHODS: Cross-sectional analysis of the 2011 wave of the Growing Up Today Study 2 cohort. We used gender-specific generalized estimating equations to examine screen time and BMI among 3071 women and 2050 men aged 16-24 years. RESULTS: Among women, each hour/day of online TV (0.47; confidence interval [CI]: 0.12, 0.82) and total non-broadcast TV (0.37; CI: 0.14, 0.61) was associated with higher BMI, as was watching ≥ 1/2 h week-1 of TV on hand-held devices (1.04; CI: 0.32-1.77). Active video games were associated with BMI among women, but not after restricting to those not trying to lose/maintain weight. Broadcast TV was associated with higher BMI (kg m-2 ) among women and men (P < 0.05). CONCLUSIONS: Among women, online TV, TV viewed on hand-held devices and the sum of non-broadcast TV time were associated with higher BMI. Broadcast TV was also associated with BMI in women and men.
Subject(s)
Body Mass Index , Sedentary Behavior , Television/statistics & numerical data , Video Games/adverse effects , Adolescent , Body Weight , Cohort Studies , Cross-Sectional Studies , Female , Humans , Male , Young AdultABSTRACT
BACKGROUND: Among adults, the Mediterranean dietary pattern (MDP) is inversely related to body mass index (BMI). Data are lacking on adherence to the MDP among youth in the United States and whether the MDP is related to weight change in that group. OBJECTIVE: To assess whether adherence to the MDP was associated with BMI change among adolescents. To examine temporality, we studied the association between baseline and 2-3-year changes in adherence to the MDP with concurrent changes in BMI, as well as subsequent changes in BMI over a 7-year period. METHODS: We prospectively followed 6002 females and 4916 males in the Growing Up Today Study II, aged 8-15 years in 2004, living across United States. Data were collected by questionnaire in 2004, 2006, 2008 and 2011. Dietary intake was assessed by the Youth/Adolescent Questionnaire. The KidMed Index was derived to measure the adherence to the MDP. We used generalized estimating equations with repeated measures within subjects to assess the association between MDP and BMI change. RESULTS: A two-point increment in the KidMed Index was independently associated with a lower gain in BMI (-0.04 kg m(-2); P=0.001). A greater increase in adherence to the KidMed Index was independently related to a lower gain in BMI in both the concurrent (P-for-trend<0.001) and the subsequent period (P-for-trend=0.002). CONCLUSIONS: Adherence to MDP was inversely associated with change in BMI among adolescents. Two-year improvement in adherence to MDP was independently associated with less steep gain in the BMI in both the concurrent and the subsequent period.
