Youth sleep durations and school start times: a cross-sectional analysis of the COMPASS study.

OBJECTIVES: This study explored school start times (SST) in relation to sleep duration and adherence to guidelines among Canadian youth.

METHODS: Using Year 4 (2015/2016) data from the Cannabis, Obesity, Mental health, Physical activity, Alcohol use, Smoking, and Sedentary behaviour (COMPASS) study, the sample included 35,821 grade 9-12 students at 78 secondary schools in Ontario and Alberta, Canada. Random intercepts models tested student-reported sleep duration and whether students met sleep recommendations, as a function of SST, controlling for student- (race/ethnicity, grade, sex, travel mode to school) and school-level (school-area urbanicity and median household income) correlates.

RESULTS: For each hour delay in SST, students reported an average of almost 7 minutes longer sleep and had 1.17 (adjusted odds ratio; 95% confidence interval, 1.04-1.31) higher odds of meeting the recommendations, with other factors held constant.

CONCLUSIONS: Potential impacts on student sleep require consideration when deciding on school schedules. Delayed SST warrant further exploration as an intervention to help ameliorate the widespread sleep deprivation found among Canadian youth.