Excessive daytime sleepiness and sleep behavior among Japanese adolescents: A nation-wide representative survey

Although a number of previous studies have examined the prevalence of excessive daytime sleepiness (EDS) among adolescents, there have been very few nationwide studies. Therefore, we conducted a cross-sectional nationwide study to clarify the prevalence of EDS and associated factors among Japanese adolescents. The survey was performed from December 2007 to March 2008 on students enrolled in randomly selected junior and senior high schools throughout Japan, using self-administered questionnaires. Of 90 361 questionnaires collected, 87 233 were analyzed. The Japanese version of the Epworth Sleepiness Scale (JESS) was used to measure EDS, which was defined as a JESS score of > 10. The prevalence (and 95% confidence interval) of EDS among males was 28.1% (27.7-28.5%), and that among females was 38.4% (37.9-38.9%). Multivariate analysis revealed that female sex, higher school grade, poor assessment of subjective sleep, late bedtime, parasomnia symptoms, long commuting time, poor mental health, drinking alcohol, smoking, and participating in extracurricular activities had significantly higher odds ratios for EDS. In conclusion, EDS in Japanese adolescents is common and associated with multiple factors.