title: Prolonged sleep increases the risk of intracerebral haemorrhage: a nationwide case-control study.
abstract: Although abnormal sleep duration is positively associated with increased risk for cardiovascular disease and mortality, the specific impact on intracerebral haemorrhage (ICH) risk remains unclear. The relationship between sleep duration and the risk of ICH was investigated in our study.
  
  
  
  A nationwide, multicentre matched case-control study was performed to investigate the risk factors for haemorrhagic stroke, using patients from 33 hospitals in Korea. In all, 490 patients with ICH and 980 age- and sex-matched controls were enrolled. Detailed information regarding sleep, sociodemographic factors, lifestyle and medical history before ICH onset was obtained using qualified structured questionnaires. Sleep duration was categorized and the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using a conditional logistic regression with 7 h as the reference duration.
  
  
  
  The number of subjects with long sleep duration, more than 8 h, was significantly greater in the ICH group than in the control group (≥8 h, 30.4% vs. 22.6%, P = 0.002). After controlling for relevant confounding factors, longer sleep duration was found to be independently associated with the risk of ICH in a dose-response manner (8 h, OR 1.57, 95% CI 1.00-2.47; ≥9 h, OR 5.00, 95% CI 2.18-11.47).
  
  
  
  Our study suggested that long sleep duration is positively associated with an increased ICH risk in a dose-dependent manner. Further studies on the relationship linking long sleep duration with increased risk of ICH are required.
authors.affiliation: Department of Neurology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: T J
authors.initials: TJ
authors.lastname: Kim
authors.affiliation: Department of Neurology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: C K
authors.initials: CK
authors.lastname: Kim
authors.affiliation: Department of Neurology, Bucheon St Mary's Hospital, Gyeonggi-do, South Korea.
authors.forename: Y
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Radiology, Seoul National University Bundang Hospital, Gyeonggi-do, Korea.
authors.forename: S
authors.initials: S
authors.lastname: Jung
authors.affiliation: Department of Neurology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: H-G
authors.initials: HG
authors.lastname: Jeong
authors.affiliation: Department of Neurology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: S J
authors.initials: SJ
authors.lastname: An
authors.affiliation: Department of Neurology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: S-B
authors.initials: SB
authors.lastname: Ko
authors.affiliation: Department of Neurology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: B-W
authors.initials: BW
authors.lastname: Yoon
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002543:Cerebral Hemorrhage / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D056910:Republic of Korea; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*; D020521:Stroke / Q000209:etiology*; D013997:Time Factors
keywords: case−control study; intracerebral haemorrhage; lifestyle; long sleep duration; risk factors; sociodemographic factors