Changes in Sleep Duration and Timing During the Middle-to-High School Transition

Abstract

Purpose: The purpose of the study was to quantify changes in sleep during the middle-to-high school transition and determine if changes in sleep differ by sociodemographic characteristics.

Methods: Adolescents were enrolled in eighth grade and followed into ninth grade (N = 110; 2,470 nights observed). The outcomes were actigraphy-estimated sleep duration, sleep onset, sleep offset, and sleep sufficiency (≥8 hours of sleep). The exposures were school grade (eighth or ninth), school night status (school or nonschool), sex (female or male), and race (white, black, or other).

Results: On school nights, sleep duration declined by 25.8 minutes per night (p < .001) from eighth to ninth grade. There was no change in sleep duration on nonschool nights. Timing of sleep onset was 22.2 minutes later on school nights (p < .001) and 17.4 minutes later on nonschool nights (p < .001) in ninth grade. Timing of sleep offset did not change on school mornings but was 22.2 minutes later on nonschool mornings (p < .001) in ninth grade. The proportion of school nights (and nonschool nights) with sleep duration ≥8 hours was 9.4% (38.3%) in eighth grade and 5.7% (35.9%) in ninth grade. The odds of sleeping ≥8 hours per night was 42% lower in ninth grade, compared toeighth grade (odds ratio = .58; 95% confidence interval: .37, .91). Males were 59% less likely to sleep ≥8 hours per night. Black adolescents were 51% less likely to sleep ≥8 hours per night.

Conclusions: Insufficient sleep is highly prevalent, especially on school nights and among male and black adolescents, and this problem worsens with the transition to high school.

Keywords: Actigraphy; Adolescence; Disparities; Longitudinal; Sex differences; Sleep.

Conflict of interest statement

Conflict of Interest:

The authors have no conflicts of interests relevant to this article to disclose.

Copyright © 2020 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1.

Enrollment, retention and actigraphy sleep data. Abbreviations: AW2, Actiwatch-2 (the actigraphy device used to objectively measure sleep patterns). *Three participants did not provide actigraphy data in 8th grade, but were retained and provided actigraphy data in 9th grade; therefore, the analytical sample includes 110 participants (i.e., 107 participants with at least 8th grade AW2 data plus 3 participants with only 9th grade AW2 data).

Figure 2.

Sleep duration, onset and offset changes during the middle-to-high school transition (8th to 9th grade). The light shading represents non-school nights and the dark shading represents school nights.

Figure 3.

Demographic factor associations with the sleep outcomes. Main associations are presented in panels A (sleep duration), B (sleep sufficiency), C (sleep onset) and D (sleep offset). Delta (Δ): difference from the referent group for each demographic factor. Sex specific sleep duration associations on school and non-school nights are in panel E (based on significant sex x school night status interaction). The log-scale is used to present the odds ratios in panel B.

Figure 4.

Demographic factor associations with the sleep quality outcomes. Main associations are presented in panels A (awakenings), B (efficiency), C (wake after sleep onset) and D (sleep onset latency). Delta (Δ): difference from the referent group for each demographic factor. Sex specific night awakenings associations on school and non-school nights are in panel E (based on significant sex x school night status interaction). The log-scale is used to present the odds ratios in panel B, C and D.