title: Prevalence and Correlates of Insufficient Sleep Syndrome in Japanese Young Adults: A Web-Based Cross-Sectional Study.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Somnology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Morita
authors.affiliation: Department of Somnology, Tokyo Medical University, Tokyo, Japan.|Department of Life Sciences and Bioinformatics, Division of Biomedical Laboratory Sciences, Graduate School of Health Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Taeko
authors.initials: T
authors.lastname: Sasai-Sakuma
authors.affiliation: Department of Psychology and Humanities, Edogawa University, Chiba, Japan.|Sleep Research Institute, Edogawa University, Chiba, Japan.
authors.forename: Shoichi
authors.initials: S
authors.lastname: Asaoka
authors.affiliation: Department of Somnology, Tokyo Medical University, Tokyo, Japan.|Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D000328:Adult; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000453:epidemiology; D005260:Female; D006306:Health Surveys / Q000706:statistics & numerical data*; D006801:Humans; D020407:Internet; D007564:Japan / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D011788:Quality of Life; D012307:Risk Factors; D012892:Sleep Deprivation / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D013577:Syndrome; D055815:Young Adult
keywords: delayed sleep-wake schedule; depression; health-related quality of life; insufficient sleep syndrome; young adults