Sleeping near a small screen or TV and more screen time were linked to shorter sleep time in children, and presence of a small screen was linked to perceived insufficient rest or sleep, according to findings of a cross-sectional study published in the January 5 issue of Pediatrics. The researchers therefore warn against unrestricted screen access in children's bedrooms.
"Inadequate sleep has been identified as a risk factor for obesity and other outcomes," write Jennifer Falbe, ScD, MPH, from the Division of Community Health and Human Development, School of Public Health, University of California Berkeley, and colleagues. "Screen time and the presence of a television in the bedroom have been associated with inadequate sleep, but little is known about small screens (eg, smartphones)."
From 2012 to 2013, 2048 fourth- and seventh-grade participants in the Massachusetts Childhood Obesity Research Demonstration Study reported on sleep environments, screen time, weekday sleep duration, and perceived insufficient rest or sleep in the past week. The investigators determined associations among these variables using linear and log binomial regression.
Mean age was 10.6±1.5 years. Forty percent of participants were Hispanic, 38% were non-Hispanic white, and 10% were non-Hispanic black. More than half (54%) reported sleeping near small screens, and 75% reported sleeping in a room with a TV.
Compared with children who never slept near a small screen, those who did reported 20.6 fewer minutes of sleep (95% confidence interval [CI], –29.7 to –11.4). Prevalence of perceived insufficient rest or sleep was also 39% higher (prevalence ratio, 1.39; 95% CI, 1.21 - 1.60).
Compared with children who slept in a room with no TV, those who had a TV in their bedroom reported 18.0 fewer minutes of sleep (95% CI, –27.9 to –8.1).
Viewing TV or DVDs and playing video or computer games were also associated with shorter sleep times and higher prevalence of perceived insufficient rest or sleep (P < .01).
Small screens were associated with shorter sleep duration in non-Hispanic black than in non-Hispanic white children, and having a small screen or TV in the bedroom was associated with later bedtimes in non-Hispanic black and Hispanic than in non-Hispanic white children.
Compared with fourth-graders, seventh-graders had stronger associations between presence of a TV and later bedtime and between TV or DVD viewing and perceived insufficient rest or sleep.
Later bedtimes contributed to the associations between screens in the sleep environment and sleep disruption because students had fixed weekday waketimes for school. Physical activity attenuated the association between video or computer games and perceived insufficient rest or sleep.
Limitations of this study include its cross-sectional design and reliance on self-report.
"Although longitudinal and experimental studies are needed to confirm these associations, our findings caution against children's unfettered access to screen-based media in their rooms," the study authors conclude. "Future studies should incorporate detailed assessments of screen content to identify the types most strongly related to poor sleep. Longitudinal studies should also continue to examine the mediating contribution of sleep to screen time's impact on obesity and other outcomes."
The National Institutes of Health (NIH) funded this study, and the Centers for Disease Control and Prevention and National Center for Chronic Disease Prevention and Health Promotion supported it. The NIH Training Grant in Academic Nutrition and the American Heart Association Postdoctoral Fellowship supported Dr. Falbe's work. The study authors have disclosed no relevant financial relationships.
Pediatrics. Published online January 5, 2015. Abstract
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