Sleep duration, restfulness, and screens in the sleep environment

Abstract

Background and objective: 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.

Methods: 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.

Results: 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).

Conclusions: 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.

Keywords: adolescent; child; screen time; sleep; television.

FIGURE 1

Differences by race or ethnicity in the associations between screens in the sleep environment and weekday sleep duration and bedtime estimated from fully adjusted models (model 2). A, Minutes of sleep duration associated with sleeping near a small screen. B, Bedtime (minutes) associated with sleeping near a small screen. C, Bedtime (minutes) associated with sleeping in a room with a TV. P values for differences in associations compared with non-Hispanic white youth: ^aP < .05, ^bP < .01, ^cP < .001.

FIGURE 2

Differences by grade in the associations between (A) sleeping in a room with a TV and later bedtime (minutes) and (B) TV or DVD viewing (h/d) and perceived insufficient rest or sleep from fully adjusted models (model 2). *P < .05.