title: Insomnia and the risk of incident heart failure: a population study.
abstract: OBJECTIVE
  Insomnia is highly prevalent among heart failure patients, but only a few small studies have investigated insomnia symptoms and risk of heart failure. We aimed to assess the prospective association between self-reported insomnia symptoms and the risk of incident heart failure in a large Norwegian cohort.
  
  
  RESULTS
  Baseline data on insomnia symptoms, including difficulty initiating sleep, difficulty maintaining sleep and having non-restorative sleep, socio-demographic variables, and health status, including established cardiovascular risk factors, were collected from 54 279 men and women 20-89 years of age who participated in the Nord-Trøndelag Health study (HUNT) between 1995 and 1997 and were free from known heart failure at baseline. The cohort was followed for incident heart failure from baseline through 2008. We used Cox proportional hazard models to assess the association of baseline insomnia symptoms with the risk of heart failure. A total of 1412 cases of heart failure occurred during a mean follow-up of 11.3 years (SD = 2.9 years), either identified at hospitals or by the National Cause of Death Registry. There was a dose-dependent association between the number of insomnia symptoms and risk of heart failure. The multi-adjusted hazard ratios were 0.96 (0.57-1.61), 1.35 (0.72-2.50), and 4.53 (1.99-10.31) for people with one, two, and three insomnia symptoms, compared with people with none of the symptoms (P for trend 0.021).
  
  
  CONCLUSIONS
  Insomnia is associated with an increased risk of incident heart failure. If our results are confirmed by others and causation is proved, evaluation of insomnia symptoms might have consequences for cardiovascular prevention.
authors: Department of Public Health, Faculty of Medicine, Norwegian University of Science and Technology, NTNU, Trondheim N-7491, Norway lars.e.laugsand@ntnu.no.
authors: Lars E
authors: LE
authors: Laugsand
authors: Department of Public Health, Faculty of Medicine, Norwegian University of Science and Technology, NTNU, Trondheim N-7491, Norway.
authors: Linn B
authors: LB
authors: Strand
authors: Department of Public Health, Faculty of Medicine, Norwegian University of Science and Technology, NTNU, Trondheim N-7491, Norway HUNT Research Centre, Norwegian University of Technology and Science, Trondheim, Norway Medical Department, Nord-Trøndelag Health Trust, Levanger, Norway.
authors: Carl
authors: C
authors: Platou
authors: Department of Public Health, Faculty of Medicine, Norwegian University of Science and Technology, NTNU, Trondheim N-7491, Norway.
authors: Lars J
authors: LJ
authors: Vatten
authors: Department of Public Health, Faculty of Medicine, Norwegian University of Science and Technology, NTNU, Trondheim N-7491, Norway Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden.
authors: Imre
authors: I
authors: Janszky
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004812:Epidemiologic Methods; D005260:Female; D006333:Heart Failure / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D011379:Prognosis; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications* / Q000453:epidemiology; D055815:Young Adult
keywords: Heart failure; Insomnia; Prospective study