Dataset Information

Association of Delaying School Start Time With Sleep Duration, Timing, and Quality Among Adolescents.

ABSTRACT:

Importance

Sleep is a resource that has been associated with health and well-being; however, sleep insufficiency is common among adolescents.

Objective

To examine how delaying school start time is associated with objectively assessed sleep duration, timing, and quality in a cohort of adolescents.

Design, setting, and participants

This observational cohort study took advantage of district-initiated modifications in the starting times of 5 public high schools in the metropolitan area of Minneapolis and St Paul, Minnesota. A total of 455 students were followed up from grade 9 (May 3 to June 3, 2016) through grade 11 (March 15 to May 21, 2018). Data were analyzed from February 1 to July 24, 2019.

Exposures

All 5 participating schools started early (7:30 am or 7:45 am) at baseline (2016). At follow-up 1 (2017) and continuing through follow-up 2 (2018), 2 schools delayed their start times by 50 and 65 minutes, whereas 3 comparison schools started at 7:30 am throughout the observation period.

Main outcomes and measures

Wrist actigraphy was used to derive indices of sleep duration, timing, and quality. With a difference-in-difference design, linear mixed-effects models were used to estimate differences in changes in sleep time between delayed-start and comparison schools.

Results

A total of 455 students were included in the analysis (among those identifying sex, 225 girls [49.5%] and 219 boys [48.1%]; mean [SD] age at baseline, 15.2 [0.3] years). Relative to the change observed in the comparison schools, students who attended delayed-start schools had an additional mean 41 (95% CI, 25-57) objectively measured minutes of night sleep at follow-up 1 and 43 (95% CI, 25-61) at follow-up 2. Delayed start times were not associated with falling asleep later on school nights at follow-ups, and students attending these schools had a mean difference-in-differences change in weekend night sleep of -24 (95% CI, -51 to 2) minutes from baseline to follow-up 1 and -34 (95% CI, -65 to -3) minutes from baseline to follow-up 2, relative to comparison school participants. Differences in differences for school night sleep onset, weekend sleep onset latency, sleep midpoints, sleep efficiency, and the sleep fragmentation index between the 2 conditions were minimal.

Conclusions and relevance

This study found that delaying high school start times could extend adolescent school night sleep duration and lessen their need for catch-up sleep on weekends. These findings suggest that later start times could be a durable strategy for addressing population-wide adolescent sleep deficits.

SUBMITTER: Widome R

PROVIDER: S-EPMC7186915 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background and objectiveThe high prevalence of obesity is a serious problem, and sleep is considered to be a factor for obesity. This study aimed to examine the relationship between sleep duration, sleep quality, and weight status among children and adolescents in China and to explore whether the relationship between sleep duration and weight status is independent of sleep quality. Sex and age differences were also explored.MethodsA cross-sectional research was conducted among 2019 children and adolescents (1029 boys and 990 girls) aged 8-16 years in Shanghai. An open-question was used to obtain data on sleep duration, which was categorized into the following four groups based on the age-specific National Sleep Foundation Sleep Duration Recommendations: 1) very short, 2) short, 3) recommended, and 4) long. The Pittsburgh Sleep Quality Index was used to assess sleep quality. Weight and height were measured for all participants. The variable weight status was estimated with the Chinese children and adolescent age- and sex-specific body mass index (BMI) and was categorized into overweight/obesity and normal weight.ResultsShort sleep duration (7-8 and 6-7 h for 6-13 and 14-16 years old, respectively) significantly increased odds of overweight/obesity (OR = 1.32, 95% CI: 1.06-1.64) compared with that of the recommended sleep duration (9-11 and 8-10 h for 6-13 and 14-16 years old, respectively). The relationship between the two variables existed independent of sleep quality. No significant relationship was found between sleep quality and overweight/obesity of children and adolescents. Sleep quality (OR = 1.07, 95% CI: 1.01-1.14) and short sleep duration (OR = 1.51, 95% CI: 1.06-2.13) increased the risk for overweight/obesity among girls, whereas no significant relationships between sleep duration, sleep quality, and overweight/obesity were found among boys. Short sleep duration increased the risk of overweight/obesity in children aged 8-13 years (OR = 1.34, 95% CI: 1.05-1.71), independent of sleep quality, but no significant relationships between these two variables existed for adolescents aged 14-16 years.ConclusionsOverall, short sleep duration increased the risks of overweight/obesity in children and adolescents in China, independent of sleep quality. This relationship is significant for girls and children aged 8-13 years instead of boys and adolescents aged 14-16 years. Interventions to extend the sleep duration of children and adolescents, especially girls and children aged 8-13 years in China, are necessary to improve their weight status.