Prevalence and Correlates of Insufficient Sleep Syndrome in Japanese Young Adults: A Web-Based Cross-Sectional Study

Study Objectives: This study investigated the prevalence and risk factors of insufficient sleep syndrome (ISS), and factors associated with daytime dysfunction in the disorder in Japanese young adults. Methods: In this cross-sectional study, a web-based questionnaire survey was used to assess demographic variables, sleep habits and quality, depressive symptoms, and health-related quality of life (HRQOL) in 2,276 participants aged 20-25. Results: Eleven percent of participants were classified as having ISS. Multiple logistic regression analysis revealed that the presence of ISS was significantly associated with social status (student or full-time employee). The participants with ISS had significantly higher depression scores and lower mental component summary scores than healthy sleepers. In the participants with ISS, a delayed sleep-wake schedule was extracted as a factor associated with worse mental component summary. Conclusions: Results indicate a relatively high proportion of Japanese young adults suffer from ISS, and that the condition is associated with a social status of student or full-time employee. Moreover, a delayed sleep-wake schedule may lead to further deterioration of mental HRQOL in ISS-affected persons.