title: Long sleep duration is associated with higher mortality in older people independent of frailty: a 5-year cohort study.
abstract: OBJECTIVE
  Although general adult population studies show a U-shaped association between sleep duration and mortality, prolonged rather than short sleep duration was more consistently associated with higher mortality in older populations. Failing health or frailty is a possible mechanism. Thus, we examined the relationship among sleep duration, frailty status, and mortality in an elderly cohort.
  
  
  METHODS
  A total of 3427 community-living adults 65 years or older were examined for general health, mood, subjective sleep measures (insomnia, napping, sleep apnea, nighttime sleep duration, sleep medications), frailty, and 5-year mortality.
  
  
  RESULTS
  After 5 years, 12.9% of men and 4.5% of women had died. Mean nighttime sleep duration was 7.3 hours. Proportion of participants who slept 10 or more hours increased with increasing frailty. Age-adjusted hazard ratio (HR) for 5-year mortality of long nighttime sleep (≥ 10 hours) was 2.10 (95% confidence interval [CI] 1.33-3.33) in men, and 2.70 (95% CI 0.98-7.46) in women. The HR in men was attenuated (HR 1.75; 95% CI 1.09-2.81) after adjustment for frailty and other covariates, whereas that of women strengthened (HR 2.88; 95% CI 1.01-8.18). Mortality increased sharply with nighttime sleep of 10 hours or more. Nighttime sleep of 10 or more hours (HR 1.75, men; HR 2.88, women) and frailty (HR 2.43, men; HR 2.08, P = .08 in women) were independently associated with 5-year mortality after full adjustment for covariates.
  
  
  CONCLUSIONS
  Frailty and long nighttime sleep duration of 10 or more hours were independently associated with 5-year mortality in older adults.
authors: Division of Geriatrics, Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China; The S. H. Ho Centre for Gerontology and Geriatrics, The Chinese University of Hong Kong, Hong Kong SAR, China; Department of Medicine and Geriatrics, Shatin Hospital, Hong Kong SAR, China. Electronic address: jennylee@cuhk.edu.hk.
authors: Jenny S W
authors: JS
authors: Lee
authors: The S. H. Ho Centre for Gerontology and Geriatrics, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors: T W
authors: TW
authors: Auyeung
authors: The Jockey Club Centre for Osteoporosis Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors: Jason
authors: J
authors: Leung
authors: The Jockey Club Centre for Osteoporosis Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors: Dicken
authors: D
authors: Chan
authors: Division of Geriatrics, Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors: Timothy
authors: T
authors: Kwok
authors: Division of Geriatrics, Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China; The S. H. Ho Centre for Gerontology and Geriatrics, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors: Jean
authors: J
authors: Woo
authors: Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors: Y K
authors: YK
authors: Wing
mesh_terms: D000368:Aged; D005260:Female; D016330:Frail Elderly; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D009026:Mortality; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000453:epidemiology*; D013997:Time Factors
keywords: Elderly; frailty; mortality; sleep duration