Relationship Between Sleep Irregularity and School Non-Attendance Among Japanese Elementary and Junior High School Students

<b>Background/Objectives</b>: In Japan, the number of elementary and junior high school students who do not attend school is increasing. Sleep problems are considered a contributing factor. <b>Methods</b>: This study utilized self-administered questionnaires about the sleep patterns and backgrounds of 25,257 students from the 3rd-10th grades across 91 elementary schools, 51 junior high schools, and 36 high schools in Japan. Latent class analysis was performed to assess sleep regularity. Logistic regression analysis was conducted to examine the relationship between sleep regularity and school attendance status, as well as the relationship with protective factors against non-attendance. <b>Results</b>: Overall, 19,005 students responded. The response rate was 75.2%. Sleep regularity was categorized into Class 1, Regular; Class 2, Somewhat Irregular; Class 3, Irregular; and Class 4, Schedule-Dependent. Class 1 decreased with grade, from 61.8% in the 3rd grade to 46.2% in the 10th grade. Class 3 comprised 10.0% of students not experiencing school non-attendance, 37.9% among students with persistent school non-attendance, and 17.9% among students who had resumed school attendance after school non-attendance in the previous year. Classes 2, 3, and 4 showed a negative relationship with protective factors against non-attendance such as good relationships with teachers and family, good communication, academic performance, proficiency in athletic activities, and the presence of a place to belong outside school. <b>Conclusions</b>: Sleep irregularity is related to school non-attendance and may serve as a barometer of students' communication and academic difficulties. Additionally, we propose an early intervention for sleep problems to prevent the exacerbation of school non-attendance.