Study objective: To examine the prevalence and correlates of sleep problems in Japanese adolescents.
Design and setting: The survey was designed as a cross-sectional sampling. The targets of the survey were junior and senior high schools throughout Japan. Sample schools were selected by stratified cluster sampling. Self-reported anonymous questionnaires were sent to sample schools for all students to fill out.
Participants: A total of 107,907 adolescents responded, and 106,297 questionnaires were subjected to analysis.
Measurements and results: The overall prevalences of sleep problems in the month preceding the questionnaire were difficulty initiating sleep (boys: 15.3%, girls: 16.0%); nocturnal sleep duration less than 6 hours (boys: 28.7%, girls: 32.6%); excessive daytime sleepiness (boys: 33.3%, girls: 39.2%), and subjectively insufficient sleep (boys: 38.1%, girls: 39.0%). Multiple logistic regression analysis showed that female sex, being a senior high-school student, and having an unhealthy lifestyle (psychological stress, smoking, and drinking alcohol) were risk factors for sleep problems.
Conclusion: Self-reported sleep problems in Japanese adolescents were common and were associated with multiple factors. There is a need for health education directed at solving sleep problems in Japanese adolescents.