title: Sleep Duration and the Risk of Mortality From Stroke in Japan: The Takayama Cohort Study.
abstract: BACKGROUND
  Few studies have assessed the associations between sleep duration and stroke subtypes. We examined whether sleep duration is associated with mortality from total stroke, ischemic stroke, and hemorrhagic stroke in a population-based cohort of Japanese men and women.
  
  
  METHODS
  Subjects included 12 875 men and 15 021 women aged 35 years or older in 1992, who were followed until 2008. The outcome variable was stroke death (ischemic stroke, hemorrhagic stroke, and total stroke).
  
  
  RESULTS
  During follow-up, 611 stroke deaths (354 from ischemic stroke, 217 from hemorrhagic stroke, and 40 from undetermined stroke) were identified. Compared with 7 h of sleep, ≥9 h of sleep was significantly associated with an increased risk of total stroke and ischemic stroke mortality after controlling for covariates. Hazard ratios (HRs) and 95% confidence intervals (CIs) were 1.51 (95% CI, 1.16-1.97) and 1.65 (95% CI, 1.16-2.35) for total stroke mortality and ischemic stroke mortality, respectively. Short sleep duration (≤6 h of sleep) was associated with a decreased risk of mortality from total stroke (HR 0.77; 95% CI, 0.59-1.01), although this association was of borderline significance (P = 0.06). The trends for total stroke and ischemic stroke mortality were also significant (P < 0.0001 and P = 0.0002, respectively). There was a significant risk reduction of hemorrhagic stroke mortality for ≤6 h of sleep as compared with 7 h of sleep (HR 0.64; 95% CI, 0.42-0.98; P for trend = 0.08). The risk reduction was pronounced for men (HR 0.31; 95% CI, 0.16-0.64).
  
  
  CONCLUSIONS
  Data suggest that longer sleep duration is associated with increased mortality from total and ischemic stroke. Short sleep duration may be associated with a decreased risk of mortality from hemorrhagic stroke in men.
authors.affiliation: Department of Epidemiology and Preventive Medicine, Gifu University Graduate School of Medicine.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kawachi
authors.forename: Keiko
authors.initials: K
authors.lastname: Wada
authors.forename: Kozue
authors.initials: K
authors.lastname: Nakamura
authors.forename: Michiko
authors.initials: M
authors.lastname: Tsuji
authors.forename: Takashi
authors.initials: T
authors.lastname: Tamura
authors.forename: Kie
authors.initials: K
authors.lastname: Konishi
authors.forename: Chisato
authors.initials: C
authors.lastname: Nagata
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012306:Risk; D012890:Sleep; D020521:Stroke / Q000401:mortality*; D013997:Time Factors