title: Long sleep duration in elders without dementia increases risk of dementia mortality (NEDICES).
abstract: OBJECTIVE
  To determine in a population-based study whether long sleep duration was associated with increased risk of dementia mortality.
  
  
  METHODS
  In this prospective, population-based study of 3,857 people without dementia aged 65 years and older (NEDICES [Neurological Disorders in Central Spain]), participants reported their daily sleep duration. The average daily total sleep duration was grouped into 3 categories: ≤5 hours (short sleepers), 6-8 hours (reference category), and ≥9 hours (long sleepers). Community-dwelling elders were followed for a median of 12.5 years, after which the death certificates of those who died were examined.
  
  
  RESULTS
  A total of 1,822 (47.2%) of 3,857 participants died, including 201 (11.0%) deaths among short sleepers, 832 (45.7%) among long sleepers, and 789 (43.3%) among those participants in the reference category. Of 1,822 deceased participants, 92 (5.1%) had a dementia condition reported on the death certificate (49 [53.3%] were long sleepers, 36 [39.1%] reported sleeping between 6 and 8 hours, and 7 [7.6%] were short sleepers). In an unadjusted Cox model, risk of dementia-specific mortality was increased in long sleepers (hazard ratio for dementia mortality in long sleepers = 1.58, p = 0.04) when compared with the reference group. In a Cox model that adjusted for numerous demographic factors and comorbidities, the hazard ratio for dementia mortality in long sleepers was 1.63 (p = 0.03).
  
  
  CONCLUSIONS
  Self-reported long sleep duration was associated with 58% increased risk of dementia-specific mortality in this cohort of elders without dementia. Future studies are required to confirm these findings.
authors.affiliation: From the Department of Neurology (J.B.-L., A.V.-G., J.P.R., F.B.-P.), University Hospital 12 de Octubre, Madrid; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) (J.B.-L., F.B.-P.), Spain; Department of Medicine (J.B.-L., A.V.-G., J.P.R., F.B.-P.), Complutense University, Madrid, Spain; G.H. Sergievsky Center (E.D.L.), Department of Neurology (E.D.L.), and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (E.D.L.), College of Physicians and Surgeons, Columbia University; Department of Epidemiology (E.D.L.), Mailman School of Public Health, Columbia University, New York; and Faculty of Biosanitary Sciences (J.P.R.), Francisco de Vitoria University, Pozuelo de Alarcón, Madrid, Spain. jbenitol67@gmail.com.
authors.forename: Julián
authors.initials: J
authors.lastname: Benito-León
authors.affiliation: From the Department of Neurology (J.B.-L., A.V.-G., J.P.R., F.B.-P.), University Hospital 12 de Octubre, Madrid; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) (J.B.-L., F.B.-P.), Spain; Department of Medicine (J.B.-L., A.V.-G., J.P.R., F.B.-P.), Complutense University, Madrid, Spain; G.H. Sergievsky Center (E.D.L.), Department of Neurology (E.D.L.), and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (E.D.L.), College of Physicians and Surgeons, Columbia University; Department of Epidemiology (E.D.L.), Mailman School of Public Health, Columbia University, New York; and Faculty of Biosanitary Sciences (J.P.R.), Francisco de Vitoria University, Pozuelo de Alarcón, Madrid, Spain.
authors.forename: Elan D
authors.initials: ED
authors.lastname: Louis
authors.affiliation: From the Department of Neurology (J.B.-L., A.V.-G., J.P.R., F.B.-P.), University Hospital 12 de Octubre, Madrid; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) (J.B.-L., F.B.-P.), Spain; Department of Medicine (J.B.-L., A.V.-G., J.P.R., F.B.-P.), Complutense University, Madrid, Spain; G.H. Sergievsky Center (E.D.L.), Department of Neurology (E.D.L.), and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (E.D.L.), College of Physicians and Surgeons, Columbia University; Department of Epidemiology (E.D.L.), Mailman School of Public Health, Columbia University, New York; and Faculty of Biosanitary Sciences (J.P.R.), Francisco de Vitoria University, Pozuelo de Alarcón, Madrid, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Villarejo-Galende
authors.affiliation: From the Department of Neurology (J.B.-L., A.V.-G., J.P.R., F.B.-P.), University Hospital 12 de Octubre, Madrid; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) (J.B.-L., F.B.-P.), Spain; Department of Medicine (J.B.-L., A.V.-G., J.P.R., F.B.-P.), Complutense University, Madrid, Spain; G.H. Sergievsky Center (E.D.L.), Department of Neurology (E.D.L.), and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (E.D.L.), College of Physicians and Surgeons, Columbia University; Department of Epidemiology (E.D.L.), Mailman School of Public Health, Columbia University, New York; and Faculty of Biosanitary Sciences (J.P.R.), Francisco de Vitoria University, Pozuelo de Alarcón, Madrid, Spain.
authors.forename: Juan P
authors.initials: JP
authors.lastname: Romero
authors.affiliation: From the Department of Neurology (J.B.-L., A.V.-G., J.P.R., F.B.-P.), University Hospital 12 de Octubre, Madrid; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) (J.B.-L., F.B.-P.), Spain; Department of Medicine (J.B.-L., A.V.-G., J.P.R., F.B.-P.), Complutense University, Madrid, Spain; G.H. Sergievsky Center (E.D.L.), Department of Neurology (E.D.L.), and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (E.D.L.), College of Physicians and Surgeons, Columbia University; Department of Epidemiology (E.D.L.), Mailman School of Public Health, Columbia University, New York; and Faculty of Biosanitary Sciences (J.P.R.), Francisco de Vitoria University, Pozuelo de Alarcón, Madrid, Spain.
authors.forename: Félix
authors.initials: F
authors.lastname: Bermejo-Pareja
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018672:Community Health Planning; D003704:Dementia / Q000453:epidemiology* / Q000401:mortality*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D012189:Retrospective Studies; D057566:Self Report; D012893:Sleep Wake Disorders / Q000453:epidemiology*; D018709:Statistics, Nonparametric