title: Prognostic significance of the nocturnal decline in blood pressure in individuals with and without high 24-h blood pressure: the Ohasama study.
abstract: OBJECTIVE
  To examine the relationship between the normal nocturnal decline in blood pressure and the risk of cardiovascular mortality in individuals with and without high 24-h blood pressure values.
  
  
  METHODS
  We obtained 24-h ambulatory blood pressure readings from 1542 residents of Ohasama, Japan, who were aged 40 years or more and were representative of the Japanese general population. We then followed up their survival for a mean of 9.2 years. The relationship was analysed using a Cox proportional hazards model adjusted for possible confounding factors.
  
  
  RESULTS
  There was a linear relationship between the nocturnal decline in blood pressure and cardiovascular mortality. On average, each 5% decrease in the decline in nocturnal systolic/diastolic blood pressure was associated with an approximately 20% greater risk of cardiovascular mortality. There were no significant interactions for the risk between 24-h systolic/diastolic blood pressure values and continuous values for the nocturnal decline in blood pressure ( for interaction 0.6). Even when 24-h blood pressure values were within the normal range ( 135/80 mmHg, average 118/69 mmHg), diminished nocturnal decreases in systolic/diastolic blood pressure were associated with an increased risk of cardiovascular mortality.
  
  
  CONCLUSIONS
  This is the first study to demonstrate that a diminished nocturnal decline in blood pressure is a risk factor for cardiovascular mortality, independent of the overall blood pressure load during a 24-h period, in the general population.
authors.affiliation: Departments of Public Health, Clinical Pharmacology and Therapeutics, and Environmental Health Science, Tohoku University School of Medicine and Pharmaceutical Science, Sendai and Ohasama Hospital, Iwate, Japan. tohkubo@mail.cc.tohoku.ac.jp
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ohkubo
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hozawa
authors.forename: Junko
authors.initials: J
authors.lastname: Yamaguchi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kikuya
authors.forename: Kaori
authors.initials: K
authors.lastname: Ohmori
authors.forename: Mari
authors.initials: M
authors.lastname: Michimata
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Matsubara
authors.forename: Junichiro
authors.initials: J
authors.lastname: Hashimoto
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Hoshi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Araki
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tsuji
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Satoh
authors.forename: Shigeru
authors.initials: S
authors.lastname: Hisamichi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Imai
mesh_terms: D000368:Aged; D001794:Blood Pressure; D001795:Blood Pressure Determination; D002940:Circadian Rhythm; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors