title: Persistent insomnia is associated with mortality risk.
abstract: BACKGROUND
  Insomnia has been associated with mortality risk, but whether this association is different in subjects with persistent vs intermittent insomnia is unclear. Additionally, the role of systemic inflammation in such an association is unknown.
  
  
  METHODS
  We used data from a community-based cohort to determine whether persistent or intermittent insomnia, defined based on persistence of symptoms over a 6-year period, was associated with death during the following 20 years of follow-up. We also determined whether changes in serum C-reactive protein (CRP) levels measured over 2 decades between study initiation and insomnia determination were different for the persistent, intermittent, and never insomnia groups. The results were adjusted for confounders such as age, sex, body mass index, smoking, physical activity, alcohol, and sedatives.
  
  
  RESULTS
  Of the 1409 adult participants, 249 (18%) had intermittent and 128 (9%) had persistent insomnia. During a 20-year follow-up period, 318 participants died (118 due to cardiopulmonary disease). In adjusted Cox proportional-hazards models, participants with persistent insomnia (adjusted hazards ratio [HR] 1.58; 95% confidence interval [CI], 1.02-2.45) but not intermittent insomnia (HR 1.22; 95% CI, 0.86-1.74) were more likely to die than participants without insomnia. Serum CRP levels were higher and increased at a steeper rate in subjects with persistent insomnia as compared with intermittent (P = .04) or never (P = .004) insomnia. Although CRP levels were themselves associated with increased mortality (adjusted HR 1.36; 95% CI, 1.01-1.82; P = .04), adjustment for CRP levels did not notably change the association between persistent insomnia and mortality.
  
  
  CONCLUSIONS
  In a population-based cohort, persistent, and not intermittent, insomnia was associated with increased risk for all-cause and cardiopulmonary mortality and was associated with a steeper increase in inflammation.
authors.affiliation: Department of Medicine, University of Arizona, Tucson; Arizona Respiratory Center, University of Arizona, Tucson. Electronic address: spartha@arc.arizona.edu.
authors.forename: Sairam
authors.initials: S
authors.lastname: Parthasarathy
authors.affiliation: Arizona Respiratory Center, University of Arizona, Tucson.
authors.forename: Monica M
authors.initials: MM
authors.lastname: Vasquez
authors.affiliation: Arizona Respiratory Center, University of Arizona, Tucson; BIO5 Institute, University of Arizona, Tucson.
authors.forename: Marilyn
authors.initials: M
authors.lastname: Halonen
authors.affiliation: Department of Psychology and Psychiatry, University of Arizona, Tucson.
authors.forename: Richard
authors.initials: R
authors.lastname: Bootzin
authors.affiliation: Arizona Respiratory Center, University of Arizona, Tucson; Division of Sleep Medicine, Harvard Medical School, Boston, Mass.
authors.forename: Stuart F
authors.initials: SF
authors.lastname: Quan
authors.affiliation: Arizona Respiratory Center, University of Arizona, Tucson; BIO5 Institute, University of Arizona, Tucson.
authors.forename: Fernando D
authors.initials: FD
authors.lastname: Martinez
authors.affiliation: Department of Medicine, University of Arizona, Tucson; Arizona Respiratory Center, University of Arizona, Tucson; CREAL Centre and Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: Stefano
authors.initials: S
authors.lastname: Guerra
mesh_terms: D000328:Adult; D001130:Arizona / Q000453:epidemiology; D002097:C-Reactive Protein / Q000032:analysis; D002318:Cardiovascular Diseases / Q000401:mortality*; D002423:Cause of Death; D016000:Cluster Analysis; D015331:Cohort Studies; D016001:Confidence Intervals; D015986:Confounding Factors, Epidemiologic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007249:Inflammation / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009026:Mortality; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D007319:Sleep Initiation and Maintenance Disorders / Q000378:metabolism / Q000401:mortality / Q000503:physiopathology
chemical_list: D002097:C-Reactive Protein
keywords: Cardiovascular; Chronic insomnia; Mortality; Sleep