title: Ambulatory blood pressure, blood pressure variability and the prevalence of carotid artery alteration: the Ohasama study.
abstract: OBJECTIVE
  To investigate the association between ambulatory blood pressure (BP) variables (level, short-term variability, circadian variation and morning pressor surge) and carotid artery alteration in a general population.
  
  
  METHODS
  We measured ambulatory BP every 30 min in 775 participants (mean age 66.2 +/- 6.2 years, 68.8% women) from the Japanese general population. Short-term BP variability during the daytime and night-time were estimated as within-subject standard deviation of daytime and night-time BP, respectively. Circadian BP variation was calculated as the percentage decline in nocturnal BP. Morning pressor surge was defined as morning BP minus pre-waking BP. The extent of carotid artery alteration was evaluated as the average of common carotid intima-media thickness (IMT) and the presence of focal carotid plaque.
  
  
  RESULTS
  Daytime and night-time BP values were more closely associated with carotid artery alteration than casual BP. With mutual adjustment for daytime and night-time BP, the latter (P < 0.0001) was more closely associated with IMT, which represents diffuse arterial thickening and arteriosclerosis, than daytime BP (P = 0.2). Night-time systolic BP variability was positively associated with carotid plaque (focal atherosclerotic lesions) independently of possible confounding factors, including night-time systolic BP (P = 0.01). A diminished nocturnal decline in systolic BP was associated with a greater IMT after adjustment for confounding factors (P = 0.03). A morning pressor surge was not associated with carotid artery alteration.
  
  
  CONCLUSIONS
  Ambulatory BP levels and BP variability were closely associated with carotid artery alteration, suggesting that these parameters are independent risk factors or predictors of carotid artery alteration.
authors.affiliation: Department of Clinical Pharmacology, Tohoku University Hospital, Sendai, Aoba-ku, Japan.
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Shintani
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kikuya
authors.forename: Azusa
authors.initials: A
authors.lastname: Hara
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ohkubo
authors.forename: Hirohito
authors.initials: H
authors.lastname: Metoki
authors.forename: Kei
authors.initials: K
authors.lastname: Asayama
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Inoue
authors.forename: Taku
authors.initials: T
authors.lastname: Obara
authors.forename: Yoko
authors.initials: Y
authors.lastname: Aono
authors.forename: Takanao
authors.initials: T
authors.lastname: Hashimoto
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: D000368:Aged; D001794:Blood Pressure; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography