title: Relationships between sleep stages and changes in cognitive function in older men: the MrOS Sleep Study.
abstract: OBJECTIVE
  To investigate the associations between sleep stage distributions and subsequent decline in cognitive function in older men over time.
  
  
  METHODS
  A population-based prospective substudy of the Osteoporotic Fractures in Men Study.
  
  
  METHODS
  Six sites in the United States.
  
  
  METHODS
  Community-dwelling men aged 67 y or older (n = 2,601), who were free of probable dementia at sleep visit. Follow-up averaged 3.4 y.
  
  
  RESULTS
  Sleep stages were identified by in-home polysomnography at the initial sleep visit (2003-2005). Cognitive outcomes were assessed with the Trail Making Test Part B and Modified Mini-Mental State Examination (3MS) at sleep visit and two follow-up visits. After adjusting for multiple confounders compared with men in the lowest quartile of percent of sleep time spent in Stage N1, those in the highest quartile had a twofold increase in cognitive decline for both cognitive tests (adjusted annualized percent change/y: Trail Making Test Part B Q1 = 1.06, Q4 = 2.45, P = 0.01; 3MS Q1 = -0.27, Q4 = -0.48, P = 0.03). In addition, compared with men in the highest quartile, men in the lowest quartile of percent of sleep time in Stage R revealed more cognitive decline on the 3MS (adjusted annualized percent change/y: Q1 = -0.49, Q4 = -0.22, P = 0.003). These findings were consistent even after further adjustment of total sleep time and sleep disordered breathing. No significant relationships between other sleep stages (N2, N3) and cognitive change were found.
  
  
  CONCLUSIONS
  Increased time in Stage N1 and less time in Stage R are associated with worsening cognitive performance in older men over time.
authors.affiliation: VA Greater Los Angeles Healthcare System, Geriatric Research, Education, and Clinical Center, Los Angeles, CA.
authors.forename: Yeonsu
authors.initials: Y
authors.lastname: Song
authors.affiliation: San Francisco Coordinating Centers and California Pacific Medical Center Research Institute, San Francisco, CA.
authors.forename: Terri
authors.initials: T
authors.lastname: Blackwell
authors.affiliation: Department of Psychiatry, Neurology, and Epidemiology, School of Medicine, University of California, San Francisco, CA.
authors.forename: Kristine
authors.initials: K
authors.lastname: Yaffe
authors.affiliation: Department of Psychiatry, School of Medicine, University of California, San Diego, CA.
authors.forename: Sonia
authors.initials: S
authors.lastname: Ancoli-Israel
authors.affiliation: Department of Medicine, Brigham and Women's Hospital and Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Susan
authors.initials: S
authors.lastname: Redline
authors.affiliation: San Francisco Coordinating Centers and California Pacific Medical Center Research Institute, San Francisco, CA.
authors.forename: Katie L
authors.initials: KL
authors.lastname: Stone
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000503:physiopathology; D006306:Health Surveys; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D017286:Polysomnography; D011446:Prospective Studies; D012111:Residence Characteristics; D012891:Sleep Apnea Syndromes / Q000503:physiopathology; D012894:Sleep Stages / Q000502:physiology*; D013997:Time Factors; D014481:United States
keywords: aging; cognitive function; cohort study; sleep stages