title: Sleep duration, cognitive decline, and dementia risk in older women.
abstract: BACKGROUND
  Consistent evidence linking habitual sleep duration with risks of mild cognitive impairment (MCI) and dementia is lacking.
  
  
  METHODS
  We conducted a prospective study on 7444 community-dwelling women (aged 65-80 y) with self-reported sleep duration, within the Women's Health Initiative Memory Study in 1995-2008. Incident MCI/dementia cases were ascertained by validated protocols. Cox models were used to adjust for multiple sociodemographic and lifestyle factors, depression, cardiovascular disease (CVD), and other clinical characteristics.
  
  
  RESULTS
  We found a statistically significant (P = .03) V-shaped association with a higher MCI/dementia risk in women with either short (≤6 hours/night) or long (≥8 hours/night) sleep duration (vs. 7 hours/night). The multicovariate-adjusted hazard for MCI/dementia was increased by 36% in short sleepers irrespective of CVD, and by 35% in long sleepers without CVD. A similar V-shaped association was found with cognitive decline.
  
  
  CONCLUSIONS
  In older women, habitual sleep duration predicts the future risk for cognitive impairments including dementia, independent of vascular risk factors.
authors.affiliation: Department of Preventive Medicine, University of Southern California, Keck School of Medicine, Los Angeles, CA, USA. Electronic address: jcchen@usc.edu.
authors.forename: Jiu-Chiuan
authors.initials: JC
authors.lastname: Chen
authors.affiliation: Division of Public Health Sciences, Department of Biostatistical Sciences, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Espeland
authors.affiliation: Department of Family and Community Medicine, University of Nevada School of Medicine, Reno, NV, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Brunner
authors.affiliation: Division of Public Health Sciences, Department of Biostatistical Sciences, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Lovato
authors.affiliation: Departments of Epidemiology & Medicine, University of Iowa, Iowa City, IA, USA.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Wallace
authors.affiliation: Division of Public Health Sciences, Department of Biostatistical Sciences, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Leng
authors.affiliation: Atlanta VA Medical Center and Division of Endocrinology, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Lawrence S
authors.initials: LS
authors.lastname: Phillips
authors.affiliation: Departments of Epidemiology & Medicine, University of Iowa, Iowa City, IA, USA.
authors.forename: Jennifer G
authors.initials: JG
authors.lastname: Robinson
authors.affiliation: Department of Population Health, Medical College of Wisconsin, Milwaukee, WI, USA.
authors.forename: Jane M
authors.initials: JM
authors.lastname: Kotchen
authors.affiliation: Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Karen C
authors.initials: KC
authors.lastname: Johnson
authors.affiliation: Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: JoAnn E
authors.initials: JE
authors.lastname: Manson
authors.affiliation: Department of Medicine, Stanford University, Stanford, CA, USA.
authors.forename: Marcia L
authors.initials: ML
authors.lastname: Stefanick
authors.affiliation: University of Wisconsin Center for Women's Health Research, Madison, WI, USA.
authors.forename: Gloria E
authors.initials: GE
authors.lastname: Sarto
authors.affiliation: Department of Physical Medicine and Rehabilitation, Ohio State University, Columbus, OH, USA.
authors.forename: W Jerry
authors.initials: WJ
authors.lastname: Mysiw
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D060825:Cognitive Dysfunction / Q000209:etiology*; D003704:Dementia / Q000209:etiology*; D006970:Disorders of Excessive Somnolence / Q000150:complications*; D005260:Female; D006801:Humans; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012890:Sleep; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications*
keywords: Cognition; Cognitive decline; Cohort studies; Dementia; Elderly; Longitudinal analysis; Mild cognitive impairment; Sleep duration