Longitudinal epidemiological study of subjective sleep quality in Japanese adolescents to investigate predictors of poor sleep quality

To clarify the predictors of poor sleep quality in Japanese adolescents. In 2010, baseline surveys were administered to students at 24 randomly selected schools-10 junior high schools and 14 senior high schools-in Japan. After 2 years, follow-up surveys were administered to the same students. The questionnaires included the following five items: basic attributes, sleep status, lifestyle factors, social relationships, and mental health status. Only participants without "poor sleep quality" at baseline were included for analyses and the incidence proportion of poor sleep quality was calculated by observing the rate of poor sleep quality at follow-up. A total of 3473 students were included for analysis. During the 2 years leading to the follow-up study, the incidence proportion of poor sleep quality was 7.7% among junior high and 6.9% among senior high school students. Multivariate analyses revealed that factors associated with poor sleep quality were poor mental health, no extracurricular learning, and short sleep duration on weekdays in junior high school students and poor mental health, waking up at 7:00 or later on weekdays and short sleep duration on weekdays in senior high school students. In junior high school students, mental health status, extracurricular learning, and sleep duration could be predictors of poor sleep quality, whereas in senior high school students, mental health status, waking time, and sleep duration on weekdays could be predictors. The present findings suggest that sleep health should be promoted among junior and senior high school students.