title: Prognostic significance of night-time, early morning, and daytime blood pressures on the risk of cerebrovascular and cardiovascular mortality: the Ohasama Study.
abstract: OBJECTIVE
  To clarify whether high blood pressure (BP) at a particular time of day is associated with cerebrovascular and cardiovascular mortality risk.
  
  
  METHODS
  Cerebrovascular and cardiovascular mortality in 1360 individuals aged 40 years and older in Ohasama, Japan, was followed for an average of 10.6 years. We used 2-h moving averages of the BP (a total of 24 average BP measurements for two consecutive hours based on four BP readings taken every 30 min) to compare the predictive power of BP taken during a 24-h period given the same number of measurements. The associations between cerebrovascular and cardiovascular mortality risk and the 2-h moving averages of systolic blood pressure (2 h-SBP) recorded over 24 h were analysed using a Cox proportional hazards model after adjusting for possible confounding factors.
  
  
  RESULTS
  The total cerebrovascular and cardiovascular mortality risk was significantly associated with elevated 2 h-SBP recorded during the night and early morning periods. Haemorrhagic stroke mortality was significantly associated with elevated daytime 2 h-SBP. Cerebral infarction mortality and heart disease mortality were significantly associated with elevated night-time 2 h-SBP.
  
  
  CONCLUSIONS
  High BP at different times of day were associated with different subtypes of cerebrovascular and cardiovascular mortality risk.
authors.affiliation: Department of Clinical Pharmacology and Therapeutics, Tohoku University Graduate School of Pharmaceutical Sciences and Medicine, Sendai, Japan.
authors.forename: Hirohito
authors.initials: H
authors.lastname: Metoki
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ohkubo
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kikuya
authors.forename: Kei
authors.initials: K
authors.lastname: Asayama
authors.forename: Taku
authors.initials: T
authors.lastname: Obara
authors.forename: Azusa
authors.initials: A
authors.lastname: Hara
authors.forename: Takuo
authors.initials: T
authors.lastname: Hirose
authors.forename: Junichiro
authors.initials: J
authors.lastname: Hashimoto
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Totsune
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Hoshi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Satoh
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Imai
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods*; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000401:mortality; D002561:Cerebrovascular Disorders / Q000175:diagnosis* / Q000401:mortality; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D018570:Risk Assessment; D020521:Stroke / Q000175:diagnosis; D013997:Time Factors