title: Circadian preference links to depression in general adult population.
abstract: BACKGROUND
  Preference to time the daily activities towards the evening hours has been associated with a greater likelihood for depression in earlier studies consisting of relatively small samples.
  
  
  METHODS
  In the current study, we analyzed the relationship between chronotype and depression using a combined population-based sample of 10,503 Finnish adults aged 25 to 74 years from the two national FINRISK 2007 and 2012 health examination studies.
  
  
  RESULTS
  Our results confirmed that eveningness was significantly associated with the increased odds for a diagnosed depressive disorder, antidepressant medication, and depressive symptoms (p<0.0001 for each), after controlling for a range of depression-attributed and potential confounding factors. Regardless of depressive symptoms, Evening-types had lower systolic and diastolic blood pressures, a smaller waist circumference, and a lower body weight than other chronotypes.
  
  
  CONCLUSIONS
  A limitation to our study is that the assessment of chronotype and information about depression was based on the self-report information only. However, the big population-based sample, which is derived from a national health examination survey, is a major strength of our study.
  
  
  CONCLUSIONS
  In conclusion, our study is in line the results from the previous, smaller sample size studies confirming that Evening-types have higher risk for depression than other chronotypes. This risk is elevated even among those Evening-types with sufficient amount of sleep.
authors.affiliation: Department of Health, National Institute for Health and Welfare, FI-00271 Helsinki, Finland; Department of Biosciences, University of Helsinki, Helsinki, Finland; Orton Orthopaedics Hospital, Helsinki, Finland. Electronic address: ilona.merikanto@helsinki.fi.
authors.forename: Ilona
authors.initials: I
authors.lastname: Merikanto
authors.affiliation: Department of Health, National Institute for Health and Welfare, Turku, Finland.
authors.forename: Erkki
authors.initials: E
authors.lastname: Kronholm
authors.affiliation: Department of Health, National Institute for Health and Welfare, FI-00271 Helsinki, Finland.
authors.forename: Markku
authors.initials: M
authors.lastname: Peltonen
authors.affiliation: Department of Health, National Institute for Health and Welfare, FI-00271 Helsinki, Finland; Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland; Hospital District of North Karelia, Joensuu, Finland.
authors.forename: Tiina
authors.initials: T
authors.lastname: Laatikainen
authors.affiliation: Department of Health, National Institute for Health and Welfare, FI-00271 Helsinki, Finland.
authors.forename: Erkki
authors.initials: E
authors.lastname: Vartiainen
authors.affiliation: Department of Health, National Institute for Health and Welfare, FI-00271 Helsinki, Finland.
authors.forename: Timo
authors.initials: T
authors.lastname: Partonen
mesh_terms: D000328:Adult; D000368:Aged; D000928:Antidepressive Agents / Q000627:therapeutic use; D002940:Circadian Rhythm; D015897:Comorbidity; D003863:Depression / Q000188:drug therapy / Q000453:epidemiology* / Q000523:psychology; D003866:Depressive Disorder / Q000453:epidemiology; D005260:Female; D005387:Finland / Q000453:epidemiology; D015438:Health Behavior; D006801:Humans; D008297:Male; D008875:Middle Aged; D057566:Self Report; D020178:Sleep Disorders, Circadian Rhythm / Q000453:epidemiology* / Q000523:psychology
chemical_list: D000928:Antidepressive Agents
keywords: Alcohol; Body-mass index; Chronobiology; Diurnal; Morningness; Sleep