title: Poor sleep predicts symptoms of depression and disability retirement due to depression.
abstract: BACKGROUND
  Disturbed sleep is associated with mood disorders. Both depression and insomnia may increase the risk of disability retirement. The longitudinal links among insomnia, depression and work incapacity are poorly known.
  
  
  METHODS
  We examined association of self-reported sleep quality with incident symptoms of depression and disability retirement due to depressive disorders in a longitudinal population-based sample of twins (n=12,063 individuals). These adults were categorized by their sleep quality in 1975 and 1981, excluding individuals with depressed mood in 1975/1981. The outcomes were the Beck Depression Inventory (BDItot) and its subscale Negative Attitudes Towards Self (BDINATS) in 1990 as dichotomized measures, and the incidence of disability retirement due to depressive disorder during 1991-2004.
  
  
  RESULTS
  Onset of poor sleep between 1975 and 1981 predicted incident depression (BDItot OR=4.5, 95% CI: 2.7-7.4, BDINATS OR=2.0, 95% CI: 1.4-2.7), while persistent poor sleep showed somewhat weaker effects (BDItot; OR=2.5, 95% CI: 1.0-6.0, BDINATS OR=1.9, 95% CI: 1.1-3.3). Among those with few recent stressful life events, onset of poor sleep predicted strongly depression (BDINATS OR=9.5, 95% CI: 3.7-24.2). Likewise onset of poor sleep by 1981 increased the risk of disability retirement due to depression (OR=2.9, 95% CI: 1.8-4.9) with a similar risk among those with persistent poor sleep (OR=2.7, 95% CI: 1.3-5.7).
  
  
  CONCLUSIONS
  Lack of baseline diagnostic interviews; sleep quality based on self-report.
  
  
  CONCLUSIONS
  Poor sleep is of importance in etiology of depression and disability retirement due to depression. This emphasizes the importance of early detection and treatment of sleep disturbances.
authors.affiliation: Public Health Genomics Unit and Institute for Molecular Medicine FIMM, National Institute for Health and Welfare, Helsinki, Finland; Department of Psychiatry, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland; Finnish Institute of Occupational Health, Helsinki, Finland; Institute for Molecular Medicine FIMM, Helsinki, Finland. Electronic address: tiina.paunio@helsinki.fi.
authors.forename: Tiina
authors.initials: T
authors.lastname: Paunio
authors.affiliation: Department of Public Health, Hjelt Institute, University of Helsinki, Helsinki, Finland; Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare, Helsinki, Finland; Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland.
authors.forename: Tellervo
authors.initials: T
authors.lastname: Korhonen
authors.affiliation: Finnish Institute of Occupational Health, Helsinki, Finland.
authors.forename: Christer
authors.initials: C
authors.lastname: Hublin
authors.affiliation: Helsinki Sleep Clinic, Vitalmed Research Centre, Helsinki, Finland.
authors.forename: Markku
authors.initials: M
authors.lastname: Partinen
authors.affiliation: Department of Public Health, Hjelt Institute, University of Helsinki, Helsinki, Finland; Social Insurance Institution of Finland, Research Department, Helsinki, Finland.
authors.forename: Karoliina
authors.initials: K
authors.lastname: Koskenvuo
authors.affiliation: Department of Public Health, Hjelt Institute, University of Helsinki, Helsinki, Finland.
authors.forename: Markku
authors.initials: M
authors.lastname: Koskenvuo
authors.affiliation: Department of Public Health, Hjelt Institute, University of Helsinki, Helsinki, Finland; Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare, Helsinki, Finland; Institute for Molecular Medicine FIMM, Helsinki, Finland.
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
mesh_terms: D000328:Adult; D003863:Depression / Q000209:etiology*; D003866:Depressive Disorder / Q000209:etiology*; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D015994:Incidence; D008016:Life Change Events; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales; D012179:Retirement; D057566:Self Report; D012893:Sleep Wake Disorders / Q000523:psychology*
keywords: Cohort studies; Depression; Disability; Sleep; Sleep disorders