Associations of inadequate sleep with numerous health outcomes among youth necessitate identifying its modifiable determinants. Television (TV) has been associated with sleep curtailment, but little is known about small screens (eg, smartphones), which can be used in bed and emit notifications. Therefore, we examined associations of different screens in sleep environments with sleep duration and perceived insufficient rest or sleep.
Participants included 2048 fourth- and seventh-graders participating in the Massachusetts Childhood Obesity Research Demonstration Study in 2012 to 2013. Using linear and log binomial regression, we examined cross-sectional associations of small screens and TVs in sleep environments and screen time with weekday sleep duration and perceived insufficient rest or sleep in the past week.
Children who slept near a small screen (compared with never) reported 20.6 fewer minutes of sleep (95% confidence interval [CI], −29.7 to −11.4) and had a higher prevalence of perceived insufficient rest or sleep (prevalence ratio, 1.39; 95% CI, 1.21 to 1.60). Children who slept in a room with a TV (compared with no TV) reported 18.0 fewer minutes of sleep (95% CI, −27.9 to −8.1). TV or DVD viewing and video or computer game playing were associated with both sleep outcomes (P < .01). Some associations were stronger among Hispanic, non-Hispanic black, and older children (P < .05 for heterogeneity).
Sleeping near a small screen, sleeping with a TV in the room, and more screen time were associated with shorter sleep durations. Presence of a small screen, but not a TV, in the sleep environment and screen time were associated with perceived insufficient rest or sleep. These findings caution against unrestricted screen access in children’s bedrooms.
Comments
Re:Television, small screen and sleep in children
Dr. Kawada suggests that it would be appropriate to adjust for both physical activity and obesity in models examining the association between screens and sleep. As described in our manuscript, the fully adjusted model-model 2--already includes days of physical activity in the past week (1). Results from this model are the main results reported. As Dr. Kawada rightly notes, screen time has been found to be associated with adiposity, independent of physical activity (2). However, adjustment for obesity in our analysis is inappropriate because obesity is likely a common effect of both screens (the independent variable) and insufficient sleep (3) (the dependent variable). Thus adjustment for obesity would not reduce confounding and could instead introduce collider stratification / selection bias (4). In addition to being a consequence of insufficient sleep, obesity may also cause obstructive sleep apnea (3), in which case obesity would be on the causal pathway between screens and sleep. If this is the case, adjustment for obesity would also be inappropriate and would bias results toward the null (5). Additionally, as noted in the limitations (1), we did not collect measures of parenting style, nor did we collect measures of mental health. We agree that both would be important variables to consider in future studies.
1. Falbe J, Davison KK, Franckle RL, et al. Sleep duration, restfulness, and screens in the sleep environment. Pediatrics. 2015;135(2):e367-375.
2. Falbe J, Rosner B, Willett WC, Sonneville KR, Hu FB, Field AE. Adiposity and different types of screen time. Pediatrics. 2013;132(6):e1497-1505.
3. Knutson KL. Does inadequate sleep play a role in vulnerability to obesity? Am J Hum Biol. 2012;24(3):361-371.
4. Cole SR, Platt RW, Schisterman EF, et al. Illustrating bias due to conditioning on a collider. Int J Epidemiol. 2010;39(2):417-420.
5. Schisterman EF, Cole SR, Platt RW. Overadjustment bias and unnecessary adjustment in epidemiologic studies. Epidemiology. 2009;20(4):488-495.
Conflict of Interest:
None declared
Television, small screen and sleep in children
Falbe et al. examined the associations between different types of screens such as television and smartphones in sleep environments and sleep (duration and quality) in weekday, in 2048 children under 13-year-old (1). The authors concluded that sleeping near a small screen, sleeping with a TV in the room, and more screen times were associated with shorter sleep durations. In addition, a small screen such as smartphones in the sleep environment and screen time were associated with poor sleep quality. I have some concerns on their study.
Firstly, excessive TV viewing time in adolescent is significantly related to obesity independently of their levels of physical activity, and physical activity does not erase a risk of obesity by the excess of TV viewing time (2). de Jong et al. clarified the association between television viewing, computer use and overweight in 4072 children aged 4-13 years, concluding that television viewing and computer use were both associated with shorter sleep duration and not with less physical activity (3). In addition, the association between television viewing and overweight could not be explained by socio-demographic variables, drinking sugared drinks and eating snacks. As Falbe et al. surveyed the level of obesity and days of physical activity in the past week, and these variables should be adjusted for their multivariate analysis.
Secondly, Maras et al. reported that duration of screen time was associated with severity of depression and anxiety in 2482 adolescents, and video game playing and computer use, not TV viewing, were associated with more severe depressive symptoms, by adjusting age, sex, ethnicity, parental education, geographic area, physical activity, and body mass index (4). As I mentioned in the first query, physical activity and obesity are used in this study to confirm the association between screen use and mental disorder. As sleep duration and sleep quality are closely related with depression and anxiety, mental status should also be monitored in study by Falbe et al.
Finally, Ray and Roos conducted an 18-month follow-up to determine the effect of family characteristics such as parenting practices at meals and family involvement on the change in 745 children's lifestyle-related health behaviors (5), and less time alone at home after school predicted favorable changes in screen time, sleep duration, and soft drink intake. There are different types of sedentary behaviors, and long-term effect of screen use should also be determined by further study.
References
1. Falbe J, Davison KK, Franckle RL, et al. Sleep duration, restfulness, and screens in the sleep environment. Pediatrics. 2015;135(2):e367-e375
2. Rey-Lopez JP, Ruiz JR, Vicente-Rodriguez G, et al. Physical activity does not attenuate the obesity risk of TV viewing in youth. Pediatr Obes 2012;7(3):240-250
3. de Jong E, Visscher TL, HiraSing RA, Heymans MW, Seidell JC, Renders CM. Association between TV viewing, computer use and overweight, determinants and competing activities of screen time in 4- to 13-year-old children. Int J Obes (Lond). 2013;37(1):47-53.
4. Maras D, Flament MF, Murray M, et al. Screen time is associated with depression and anxiety in Canadian youth. Prev Med. 2015;73:133-138
5. Ray C, Roos E. Family characteristics predicting favourable changes in 10 and 11-year-old children's lifestyle-related health behaviours during an 18-month follow-up. Appetite. 2012;58(1):326-332.
Conflict of Interest:
None declared