title: Differences in effects of age and blood pressure on augmentation index.
abstract: BACKGROUND
  The effect of age on the augmentation index (AI) differs between young adults and the elderly, and the AI reaches a plateau after the age of 60 years. We examined whether the effects of age and an elevation in blood pressure on the AI differ between young adults and the elderly, between subjects with and without high blood pressure, or between subjects with and without a high AI.
  
  
  METHODS
  The radial AI was measured in 10,190 subjects who were either healthy or had hypertension (n = 5,477 men and 4,743 women).
  
  
  RESULTS
  In both sexes, a phased increase in the radial AI with age could only be confirmed up to an age of 60 years. A phased increase in the radial AI with the systolic blood pressure (SBP) could be confirmed up to an SBP of >170 mm Hg. Among subjects categorized within the highest age tertile, the highest SBP tertile, or the highest radial AI tertile, stepwise multivariable analyses demonstrated that SBP, but not age, was a significant independent factor influencing the radial AI.
  
  
  CONCLUSIONS
  The effect of age and blood pressure on AI differ not only between young adults and the elderly but also between those with and those without high blood pressure or between those with and those without a high AI. The effect of an elevation in blood pressure, but not aging, on the AI is significant in the elderly, in subjects with high blood pressure, or in those with a high AI.
authors.affiliation: Second Department of Internal Medicine, Tokyo Medical University, Tokyo, Japan; tomiyama@tokyo-med.ac.jp.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Tomiyama
authors.affiliation: Second Department of Internal Medicine, Tokyo Medical University, Tokyo, Japan;
authors.forename: Mari
authors.initials: M
authors.lastname: Odaira
authors.affiliation: Second Department of Internal Medicine, Tokyo Medical University, Tokyo, Japan;
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Kimura
authors.affiliation: Second Department of Internal Medicine, Tokyo Medical University, Tokyo, Japan;
authors.forename: Chisa
authors.initials: C
authors.lastname: Matsumoto
authors.affiliation: Second Department of Internal Medicine, Tokyo Medical University, Tokyo, Japan;
authors.forename: Kazuki
authors.initials: K
authors.lastname: Shiina
authors.affiliation: Jichi Medical University, Tochigi, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Eguchi
authors.affiliation: Jichi Medical University, Tochigi, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miyashita
authors.affiliation: Jichi Medical University, Tochigi, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Shimada
authors.affiliation: Second Department of Internal Medicine, Tokyo Medical University, Tokyo, Japan;
authors.forename: Akira
authors.initials: A
authors.lastname: Yamashina
mesh_terms: D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000503:physiopathology*; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009017:Morbidity / Q000639:trends; D017534:Radial Artery; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
keywords: age; augmentation index; blood pressure; hypertension.