Academic performance in adolescents with delayed sleep phase

Abstract

Background: Delayed sleep phase (DSP) in adolescence has been linked to reduced academic performance, but there are few population-based studies examining this association using validated sleep measures and objective outcomes.

Methods: The youth@hordaland-survey, a large population-based study from Norway conducted in 2012, surveyed 8347 high-school students aged 16-19 years (54% girls). DSP was assessed by self-report sleep measures, and it was operationalized according to the International Classification of Sleep Disorders - Second Edition. School performance (grade point average, GPA) was obtained from official administrative registries, and it was linked individually to health data.

Results: DSP was associated with increased odds for poor school performance. After adjusting for age and gender, DSP was associated with a threefold increased odds of poor GPA (lowest quartile) [odds ratio (OR) = 2.95; 95% confidence interval (CI): 2.03-4.30], and adjustment for sociodemographics and lifestyle factors did not, or only slightly, attenuate this association. Adjustment for nonattendance at school reduced the association substantially, and in the fully adjusted model, the effect of DSP on poor academic performance was reduced to a non-significant level. Mediation analyses confirmed both direct and significant indirect effects of DSP on school performance based on school absence, daytime sleepiness, and sleep duration.

Conclusion: Poor academic performance may reflect an independent effect of underlying circadian disruption, which in part could be mediated by school attendance, as well as daytime sleepiness and short sleep duration. This suggests that careful assessment of sleep is warranted in addressing educational difficulties.

Keywords: Academic performance; Adolescence; Delayed sleep phase; Epidemiology.