title: Weaker circadian activity rhythms are associated with poorer executive function in older women.
abstract: OBJECTIVE
  Older adults and patients with dementia often have disrupted circadian activity rhythms (CARs). Disrupted CARs are associated with health declines and could affect cognitive aging. We hypothesized that among older women, weaker CARs would be associated with poorer cognitive function 5 y later.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Three US clinical sites.
  
  
  METHODS
  There were 1,287 community-dwelling older women (82.8 ± 3.1 y) participating in an ongoing prospective study who were free of dementia at the baseline visit.
  
  
  RESULTS
  Baseline actigraphy was used to determine CAR measures (amplitude, mesor, and rhythm robustness, analyzed as quartiles; acrophase analyzed by peak activity time < 13:34 and > 15:51). Five years later, cognitive performance was assessed with the Modified Mini-Mental Status Examination (3MS), California Verbal Learning Task (CVLT), digit span, Trail Making Test B (Trails B), categorical fluency, and letter fluency. We compared cognitive performance with CARs using analyses of covariance adjusted for a number of health factors and comorbidities. Women in the lowest quartile for CAR amplitude performed worse on Trails B and categorical fluency compared to women in the highest quartile (group difference (d) = 30.42 sec, d = -1.01 words respectively, P < 0.05). Women in the lowest quartile for mesor performed worse on categorical fluency (d = -0.86 words, P < 0.05). Women with a later acrophase performed worse on categorical fluency (d = -0.69 words, P < 0.05). Controlling for baseline Mini-Mental State Examination and sleep factors had little effect on our results.
  
  
  CONCLUSIONS
  Weaker circadian activity rhythm patterns are associated with worse cognitive function, especially executive function, in older women without dementia. Further investigation is required to determine the etiology of these relationships.
authors.affiliation: Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA: San Francisco Veterans Administration, San Francisco, CA.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Walsh
authors.affiliation: California Pacific Medical Center Research Institute, San Francisco, CA.
authors.forename: Terri
authors.initials: T
authors.lastname: Blackwell
authors.affiliation: California Pacific Medical Center Research Institute, San Francisco, CA.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Tranah
authors.affiliation: California Pacific Medical Center Research Institute, San Francisco, CA.
authors.forename: Katie L
authors.initials: KL
authors.lastname: Stone
authors.affiliation: Department of Psychiatry, University of California, San Diego, CA.
authors.forename: Sonia
authors.initials: S
authors.lastname: Ancoli-Israel
authors.affiliation: Harvard Medical School, Division of Sleep Medicine, Boston, MA: Department of Medicine, Brigham and Women's Hospital, Boston, MA: Division of Pulmonary Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA.
authors.forename: Susan
authors.initials: S
authors.lastname: Redline
authors.affiliation: School of Public Health, University of Minnesota, Minneapolis, MN.
authors.forename: Misti
authors.initials: M
authors.lastname: Paudel
authors.affiliation: Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA: Department of Psychiatry, University of California, San Francisco, CA.
authors.forename: Joel H
authors.initials: JH
authors.lastname: Kramer
authors.affiliation: Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA: San Francisco Veterans Administration, San Francisco, CA: Department of Psychiatry, University of California, San Francisco, CA.
authors.forename: Kristine
authors.initials: K
authors.lastname: Yaffe
mesh_terms: D056044:Actigraphy; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D002940:Circadian Rhythm / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000503:physiopathology* / Q000523:psychology*; D015897:Comorbidity; D003704:Dementia; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008954:Models, Biological; D009483:Neuropsychological Tests; D011446:Prospective Studies; D012111:Residence Characteristics; D012890:Sleep / Q000502:physiology; D014481:United States
keywords: actigraphy; cognition; cognitive impairment; executive function; verbal memory