Department of Health Sciences, Brock University, Niagara Region, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada; School of Public Health and Health Systems, University of Waterloo, 200 University Ave, Waterloo, Ontario N2L 3G1, Canada.
School of Public Health and Health Systems, University of Waterloo, 200 University Ave, Waterloo, Ontario N2L 3G1, Canada.
Sleep Med. 2019 Apr;56:16-22. doi: 10.1016/j.sleep.2018.09.020. Epub 2018 Oct 12.
To date, no longitudinal population-based studies of school start times have been conducted within Canada. School schedule changes provided an opportunity to examine start times in association with youth sleep, physical activity, and screen use over time.
This longitudinal study included grade 9-12 students attending 49 Ontario secondary schools that participated in at least two consecutive years of the COMPASS study (2012-2017). Fixed effects models tested whether differences in within-student change in self-reported sleep duration, moderate-to-vigorous physical activity, and screen time were associated with school start time changes, adjusting for student- (grade, sex, ethnicity, spending money) and school-level covariates (median income, urbanicity, geographical area).
Thirteen start time changes of 5-10 min were reported. Ten-minute advances at earlier clock times (8:30 AM-8:20 AM; 8:40 AM-8:30 AM) were associated with steeper sleep duration declines than schools with consistent start times but had no effect at later times (9:00 AM-8:50 AM). While sleep change did not differ with 5-min delays, 10-min delays (8:50 AM-9:00 AM) were associated with additional sleep (23.7 min). Apart from one school that shifted from 8:30 AM to 8:35 AM, in which screen time and physical activity decreased more steeply, no effect was found for screen time, and 5-min delays were associated with more physical activity (10.9 min) and advances with less activity (-8.0 min).
Results support start time delays as a valuable strategy to help ameliorate sleep debt among youth. Interference with physical activity or increased screen time appear unlikely with modest schedule changes. Potential adverse impacts on sleep require consideration with 10-min advances.
迄今为止，加拿大尚未开展关于上学时间的纵向人群研究。学校时间表的改变为研究上学时间与青少年睡眠、身体活动和屏幕使用时间的关系提供了机会。
本纵向研究纳入了参加 COMPASS 研究（2012-2017 年）的 49 所安大略省中学的 9-12 年级学生。固定效应模型检验了学生自我报告的睡眠时间、中等到剧烈身体活动和屏幕时间的变化是否与学校开始时间的变化有关，调整了学生（年级、性别、种族、零花钱）和学校水平的协变量（中位数收入、城市化程度、地理区域）。
报告了 13 次 5-10 分钟的上学时间调整。与始终保持相同上学时间的学校相比，较早的时钟时间（8:30-8:20 AM；8:40-8:30 AM）的 10 分钟提前上学与睡眠时间下降更陡峭有关，但在较晚的时间没有影响（9:00-8:50 AM）。虽然 5 分钟的延迟不会导致睡眠时间的变化，但 10 分钟的延迟（8:50-9:00 AM）与额外的睡眠时间有关（23.7 分钟）。除了一所从 8:30 AM 改为 8:35 AM 的学校外，该学校的屏幕时间和身体活动下降更陡峭，没有发现屏幕时间的影响，而 5 分钟的延迟与更多的身体活动（10.9 分钟）有关，而提前上学与较少的活动有关（-8.0 分钟）。
结果支持推迟上学时间作为帮助青少年缓解睡眠债务的一种有效策略。适度的时间表改变不太可能干扰身体活动或增加屏幕时间。10 分钟的提前上学可能会对睡眠产生不利影响，需要考虑。
