Later high school start times associated with longer actigraphic sleep duration in adolescents. Issue 2 (3rd November 2018)

• Record Type: Journal Article
• Authors: Nahmod, Nicole G; Lee, Soomi; Master, Lindsay; Chang, Anne-Marie; Hale, Lauren; Buxton, Orfeu M
• Is Part Of: Sleep. Volume 42:Issue 2(2019)
• Publication Date: 2018-11-03
• Subjects: school start times -- actigraphy -- adolescence -- sleep duration -- sleep timing -- education policy -- pediatric sleep -- sleep quality; Sleep -- Physiological aspects -- Periodicals; Sleep disorders -- Periodicals; Sommeil -- Aspect physiologique -- Périodiques; Sommeil, Troubles du -- Périodiques; Sleep disorders; Sleep -- Physiological aspects; Sleep -- physiological aspects; Sleep Wake Disorders; Psychophysiology; Electronic journals; Periodicals; 616.8498
• DOI: 10.1093/sleep/zsy212
• Languages: English
• ISSNs: 0161-8105

Abstract

Abstract: Study Objectives: High school start times (SSTs) directly impact adolescents' sleep timing and duration. This study investigated the associations between SSTs and actigraphically-measured 24-hour sleep duration, sleep onset, sleep offset and sleep quality. Methods: This study included 383 adolescents ( M age = 15.5, SD age = 0.6 years) participating in the age 15 wave of the Fragile Families & Child Wellbeing Study, a national birth cohort study sampling from 20 large US cities. Multilevel models used daily observations ( N = 1116 school days, M days = 2.9, SD days = 1.4 per adolescent) of sleep and SSTs from concordant daily diary and actigraphy. Results: A diverse range of SSTs were included in our analyses ( M SST = 08:08, SD SST = 39 minutes, Range SST = 06:00–11:05), and are presented in the following categories for ease of interpretation: before 07:30, 07:30–07:59, 08:00–08:29, and 08:30 or later. Adolescents starting school at 08:30 or later exhibited significantly longer actigraphically-assessed 24-hour sleep duration (by 21–34 minutes, p < .05) and later sleep offset (by 32–64 minutes, p < .001) when compared with the adolescents grouped by earlier SSTs. SSTs were also analyzed continuously for comparison with existing literature, and results indicated that every 1-hour delay in SST was significantly associated with 21 minutes longer 24-hour sleep duration ( p < .001), 16 minutes later sleep onset ( p < .01), and 39 minutes later sleep offset ( p < .001). All models controlled for covariates including socioeconomic status. Conclusion: These findings support pediatric and public health expert recommendations for SSTs after 08:30. In our diverse national urban sample, adolescents with SSTs at 08:30 or later, compared with adolescents with earlier SSTs, had significantly longer actigraphy-measured sleep.