title: The relationships between insomnia, sleep apnoea and depression: findings from the American National Health and Nutrition Examination Survey, 2005-2008.
abstract: OBJECTIVE
  To determine the association between insomnia, obstructive sleep apnoea (OSA), and comorbid insomnia-OSA and depression, while controlling for relevant lifestyle and health factors, among a large population-based sample of US adults.
  
  
  METHODS
  We examined a sample of 11,329 adults (≥18 years) who participated in the National Health and Nutrition Examination Survey (NHANES) during the years 2005-2008. Insomnia was classified via a combination of self-reported positive physician diagnosis and high-frequency 'trouble falling asleep', 'waking during the night', 'waking too early', and 'feeling unrested during the day'. OSA was classified as a combination of a positive response to a physician-diagnosed condition, in addition to a high frequency of self-reported nocturnal 'snoring', 'snorting/stopping breathing' and 'feeling overly sleepy during the day'. Comorbid insomnia-OSA was further assessed by combining a positive response to either insomnia (all), or sleep apnoea (all), as classified above. Depressive symptomology was assessed by the Patient Health Questionnaire-9 (PHQ-9), with scores of >9 used to indicate depression. Odds ratios (ORs) and 95% confidence intervals (CIs) for sleep disorders and depression were attained from logistic regression modelling adjusted for sex, age, poverty level, smoking status and body mass index (BMI).
  
  
  RESULTS
  Those who reported insomnia, OSA or comorbid insomnia-OSA symptoms reported higher rates of depression (33.6%, 22.2%, 27.1%, respectively), and consistently reported poorer physical health outcomes than those who did not report sleep disorders. After adjusting for sex, age, poverty level, smoking status and BMI (kg/m(2)), insomnia (OR 6.57, 95% CI 3.89-11.11), OSA (OR 5.14, 95% CI 3.14-8.41) and comorbid insomnia-OSA (OR 6.67, 95% CI 4.44-10.00) were associated with an increased likelihood of reporting depression.
  
  
  CONCLUSIONS
  Insomnia, OSA and comorbid insomnia-OSA are associated with significant depressive symptomology among this large population-based sample of adults.
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia Institute for Breathing and Sleep, Austin Health, Melbourne, Australia achayley@deakin.edu.au.
authors.forename: Amie C
authors.initials: AC
authors.lastname: Hayley
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia.
authors.forename: Lana J
authors.initials: LJ
authors.lastname: Williams
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia.
authors.forename: Kamalesh
authors.initials: K
authors.lastname: Venugopal
authors.affiliation: Department of Psychology, College of Arts, Victoria University, Melbourne, Australia.
authors.forename: Gerard A
authors.initials: GA
authors.lastname: Kennedy
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia Department of Psychiatry, The University of Melbourne, Parkville, Australia Orygen Research Centre, Parkville, Australia Florey Institute for Neuroscience and Mental Health, Parkville, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Berk
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia NorthWest Academic Centre, Department of Medicine, The University of Melbourne, St Albans, Australia.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Pasco
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015897:Comorbidity; D003863:Depression / Q000453:epidemiology*; D005260:Female; D006306:Health Surveys / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012891:Sleep Apnea Syndromes / Q000453:epidemiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Comorbidity; National Health and Nutritional Examination Survey (NHANES); depression; epidemiology; insomnia; obstructive sleep apnoea; population