A nationwide cross-sectional study of difficulty waking up for school among adolescents

To determine the prevalence of and risk-factors for difficulty waking up for school among adolescents.

We used a self-administered questionnaire (140 junior high schools [JHSs]; 124 senior high schools [SHSs]) selected randomly in 2012 from throughout Japan.

Total response rate: 60.7%. Data from 38 494 JHS and 61 556 SHS students were analyzed. The prevalence of at least one instance of school tardiness/absence due to difficulty waking up over a 30-day period was 10.9 (95% confidence-interval:10.5-11.3)%/2.9(2.7-3.1)% for JHS-boys and 7.7(7.3-8.1)%/2.0(1.8-2.2)% for JHS-girls. The prevalence was 15.5(15.1-15.9)%/5.6(5.3-5.9)% for SHS-boys and 14.4(14.0-14.8)%/5.9(5.6-6.2)% for SHS-girls. We used ordinal regression to identify the risk factors associated with the experience of school tardiness/absence. Factors significantly associated with school tardiness in all four groups (JHS boys/girls, SHS boys/girls) were "no-participation-in-club-activities," "early-morning-awakening," "feeling bad throughout a morning," "drinking," and "smoking." Among associated factors, the highest odds ratio was found for monthly smoking-days (none vs. at least one-day or more) for JHS-girls at 5.30(3.57-7.85). Factors significantly associated with school absence in all four groups were "no wishing to go to university," "no participation in club activities," "disorders of initiating and maintaining sleep," "long internet use," "drinking," "smoking," "poor-mental-health" and "feeling bad throughout a morning." Among associated factors, the highest odds ratio was found for monthly smoking-days (none vs. at least one-day or more) for JHS-girls at 4.60(3.45-6.15).

These results suggest that the risk factors for difficulty waking up among adolescents are sleep status, lifestyle, and mental health, which can indicate the presence of an underlying disease.