Screen Time and Metabolic Risk Factors Among Adolescents

Physical Activity, Nutrition, and Obesity Research Group, University of Sydney, Camperdown, NSW 2006, Australia.
JAMA Pediatrics (Impact Factor: 5.73). 07/2010; 164(7):643-9. DOI: 10.1001/archpediatrics.2010.88
Source: PubMed


To examine the association between screen time (ST) (ie, television/DVD/video and computer use) guidelines and risk factors for cardiovascular disease, type 2 diabetes mellitus, and fatty liver diseases in mid-adolescence.
High schools in Sydney, Australia.
Grade 10 students (N = 496; 58% boys; mean [SD] age, 15.4 [0.4] years).
Body mass index, waist circumference, cardiorespiratory endurance, dietary factors, socioeconomic status, and pubertal status.
Screen time was categorized as less than 2 hours per day or 2 or more hours per day and calculated for weekday, weekend, and the entire week. Fasting blood samples were analyzed for levels of high-density lipoprotein and low-density lipoprotein cholesterol, triglycerides, insulin, and glucose; homeostasis model assessment of insulin resistance (HOMA-IR); levels of alanine aminotransferase, gamma-glutamyltransferase, and high-sensitivity C-reactive protein; and blood pressure. Abnormal results were categorized according to published guidelines.
Mean ST for all students was 3.1 hours per day and for weekdays and weekend days, 2.6 hours per day and 4.4 hours per day, respectively. Boys were more likely to exceed ST guidelines than girls (odds ratio [OR], 2.71; 95% confidence interval [CI], 1.67-4.38). There were no significant associations between ST guidelines and metabolic risk factors among girls. After adjusting for potential confounders, boys who exceeded ST guidelines on weekdays were more likely to have elevated HOMA-IR (adjusted OR, 2.42; 95% CI, 1.11-5.28) and insulin levels (adjusted OR, 2.73; 95% CI, 1.43-5.23).
Adolescent boys with ST of 2 or more hours per day on weekdays have twice the risk of abnormal levels of insulin and HOMA-IR compared with peers with ST less than 2 hours per day on weekdays. These results suggest there is an increased risk of insulin resistance among adolescent boys who do not meet ST guidelines on weekdays.

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Available from: Elizabeth Denney-Wilson
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    • "Parents’ screen behaviors were reported by only one of the parents and may be inaccurate and subject to recall bias. The measures of ST behaviors have not been validated against objective measures, but they are comparable to measures used by other studies.24,25 Also, we understand that using 2 h/day as a cut-off point may not necessarily be an appropriate approach for Chinese adolescents, but such a cut-off makes our findings comparable to those of other studies. "
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    ABSTRACT: Background Rapid urbanization in China has led to a proliferation of electronic entertainment media among youth. Prolonged screen time (ST; includes watching television and playing on computers, video game consoles, or mobile phones) is linked to poor health profiles. The aim of this study was to report recreational ST behaviors and ST correlates among Chinese adolescents living in two regions with different degrees of urbanization. Methods A cross-sectional, school-based survey (n = 3461 adolescents; aged 12–14 years old) living in inner-city Shanghai and a peri-urban region of Hangzhou. Students completed a questionnaire including family characteristics, daily ST, and information on family environment related to screen use. Recreational ST was categorized into two groups according to recommendations by the American Academy of Pediatrics (< or ≥2 h/day). Parents reported their own ST and also reported educational attainment as a proxy for socioeconomic status. Results ST was higher among boys than girls and on weekends than weekdays. Peri-urban girls were more likely to exceed 2 h/day ST compared to inner-city girls on weekends. Having a father with no university degree, mother’s TV viewing ≥2 h/day, no ST rules at home, and eating meals in front of the TV were associated with higher ST on both weekdays and weekends, and regional differences were found for weekend ST. Conclusions TV viewing and playing on the computer were the most prevalent ST behaviors among Chinese adolescents. Mobile phone playing was less prevalent but persistent throughout the week. More population-level surveillance and research is needed to monitor the trends in ST behaviors and to better understand the characteristics of those who are at risk.
    Full-text · Article · Jun 2014 · Journal of Epidemiology
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    • "Following this, there has been an emerging concern about the negative health effects of screen time activity in children and adolescents. These effects include less time for physical activity [2], poorer academic performance [3], aggressive behaviour [4], higher energy-intake [5], more physical complaints [6], higher risk of overweight [7,8] and other metabolic risk factors [9]. In addition, a recent review concluded that sedentary behaviours track at moderate levels from childhood to adolescence [10]. "
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    ABSTRACT: Background There has been an increase in screen-based communication, leading to concerns about the negative health effects of screen-based activities in children and adolescents. The present study aimed to (1) analyze changes in screen time activity in Norwegian children from 2001 to 2008, and (2) to analyze associations between the changes in screen time activity over time and sex, grade level and parental educational level. Methods Within the project Fruits and Vegetables Make the Marks (FVMM), 1488 6th and 7th grade pupils from 27 Norwegian elementary schools completed a questionnaire including a question about time spent on television viewing and personal computer use in 2001 and 1339 pupils from the same schools completed the same questionnaire in 2008. Data were analyzed by multilevel linear mixed models. Results The proportions of 6th and 7th grade pupils at the 27 schools that reported screen time activity outside school of 2 hours/day or more decreased from 55% to 45% (p<0.001) from 2001 to 2008 when adjusting for sex, grade level and parental education. The decrease was most evident in 6th graders (51% to 37%) and in children with highly educated parents (54% to 39%). Conclusion The present study shows that there has been a marked reduction in screen time activity outside school in this group of Norwegian 10–12 year olds from 2001 to 2008.
    Full-text · Article · Jan 2013 · BMC Public Health
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    • "Sedentary behavior (SB) is increasingly being investigated as an entity distinct from physical inactivity. A cross-sectional study of 496 Australian 10th grade students suggested that, among boys with >2 h of screen time daily on weekdays, the risk of abnormal levels of insulin and homeostasis model assessment of insulin resistance (HOMA-IR) is twice that of those with less than 2 h after controlling for pubertal status, adiposity, dietary habits, and endurance (13). In contrast, there were no associations between screen time and metabolic risk factors, including lipids, blood pressure, insulin, glucose, and C-reactive protein in girls (13). "
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    ABSTRACT: To describe the associations among moderate-to-vigorous physical activity (MVPA), fitness, sedentary behavior (SB), and insulin sensitivity (IS). Data were drawn from the baseline assessment of the QUALITY cohort, which included 630 white youth (aged 8-10 years at recruitment), with at least one obese biological parent. IS was measured by two fasting indices (insulin, homeostasis model assessment of insulin resistance) and an oral glucose tolerance test (OGTT)-based index (Matsuda IS index [Matsuda-ISI]). Fitness was measured by Vo(2peak); percent fat mass (PFM) was measured by dual-energy X-ray absorptiometry; 7-day MVPA was measured with accelerometry. SB indicators included average hours daily of self-report screen time (SBst), and average minutes daily at <100 counts/min from accelerometry (SBacc). Multivariable linear regression models were adjusted for age, sex, season, and puberty. MVPA and SBacc were independently associated with IS, but this was no longer statistically significant after accounting for PFM. SBst was negatively associated with IS in girls only, even after controlling for physical activity (PA), fitness, and adiposity; for each additional hour of SBst daily, IS decreased by 4.6-5.6% across all IS indices. Fitness was positively associated with IS (measured by Matsuda-ISI) after accounting for PA, SB, and PFM; for every 1 unit increase in Vo(2peak), Matsuda-ISI increased by approximately 1.0% (P < 0.05). In children with an obese parent, PA and SBacc are associated with IS, but this association is mediated by adiposity. SBst is negatively associated with IS in girls, beyond its known impact on adiposity. Finally, fitness is independently associated with better IS measured by OGTT.
    Full-text · Article · Apr 2012 · Diabetes care
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