title: The Association Between Extreme Sleep Duration and Cardiac Autonomic Control in Community-Dwelling Older Adults: The Yilan Study, Taiwan.
abstract: BACKGROUND
  The aims of the present study were to determine the associations and sex-specific relationships between extreme sleep duration and cardiac autonomic control in a cohort of older individuals.
  
  
  METHODS
  A community-based survey was conducted in Yilan City, Taiwan. Community-dwelling older adults aged ≥65 were randomly selected to participate. Extreme sleep durations were defined as either short sleep (≤5 hours) or long sleep (≥8 hours). Cardiac autonomic control was evaluated using the parameters of frequency-domain analysis of heart rate variability.
  
  
  RESULTS
  Of 1,721 participants, 58.7% were female. In multiple logistic regression analyses, short sleep duration did not correlate with any of the unhealthier parameters of heart rate variability. In contrast, long sleep duration was associated with elevated risk for poor high-frequency values (odds ratio [OR]: 1.83, 95% confidence interval [CI]: 1.34-2.50) and the unfavorable low-frequency values (OR: 1.44, 95% CI: 1.05-1.97). When stratified by sex, the associations between extreme sleep duration and poor heart rate variability were more robust in males.
  
  
  CONCLUSIONS
  Poor cardiac autonomic control may underlie the link between extreme sleep duration and adverse health outcomes in older adults. A sex-specific relationship between poor cardiac autonomic function and extreme sleep duration also was found.
authors.affiliation: Department of Psychiatry and Center of Sleep Disorders, National Taiwan University Hospital, Taipei.
authors.forename: Hsi-Chung
authors.initials: HC
authors.lastname: Chen
authors.affiliation: Division of Cardiology, Department of Internal Medicine and Community Medicine Center, National Yang-Ming University Hospital, Yilan County, Taiwan.|Department of Medicine, School of Medicine, National Yang-Ming University, Yilan County, Taiwan.
authors.forename: Nai-Wei
authors.initials: NW
authors.lastname: Hsu
authors.affiliation: Community Medicine Research Center and Institute of Public Health, College of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Pesus
authors.initials: P
authors.lastname: Chou
mesh_terms: D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology*; D005260:Female; D006306:Health Surveys; D006321:Heart / Q000294:innervation / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D057187:Independent Living / Q000706:statistics & numerical data; D008297:Male; D063868:Patient Outcome Assessment; D011897:Random Allocation; D018570:Risk Assessment / Q000379:methods; D012737:Sex Factors; D012893:Sleep Wake Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D013223:Statistics as Topic; D013624:Taiwan / Q000453:epidemiology
keywords: Cardiovascular; Epidemiology; Sleep