title: Age-dependent associations between blood pressure and coronary artery calcification in asymptomatic adults.
abstract: OBJECTIVE
  The age-dependent roles of the components of blood pressure (BP) in the development of coronary artery calcification (CAC) are poorly understood.
  
  
  METHODS
  We examined systolic (SBP), diastolic (DBP), mean arterial pressure (MAP) and pulse pressure (PP) as predictors of CAC in 830 asymptomatic, non-diabetic participants in a community-based study who were aged > or = 30 years and free of antihypertensive therapy or known cardiovascular disease.
  
  
  METHODS
  CAC was measured with electron beam computed tomography. Tobit regression was used in two age groups (< 50 years and > or = 50 years) to evaluate the relationship of BP components with presence and quantity of CAC, adjusting for traditional coronary artery disease (CAD) risk factors.
  
  
  RESULTS
  Among those aged < 50 years, CAC was positively associated with SBP, DBP and MAP, considering each pressure individually and DBP was the strongest predictor (P = 0.0088). Among those aged > or = 50 years, CAC was positively associated with SBP (P = 0.0257) and PP (P = 0.0028), considered individually. When SBP and DBP were in the same model, presence and CAC quantity were positively associated with SBP (P = 0.0024) and negatively with DBP (P = 0.0401), favoring PP as the best predictor of CAC.
  
  
  CONCLUSIONS
  SBP, DBP and PP have age-dependent roles in the prediction of CAC similar to their roles in prediction of future CAD events. These observations provide new evidence supporting the measurement of CAC as a surrogate of target organ disease and subsequently, as a predictor of increased risk of future CAD events.
authors.affiliation: Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, 48104-3028, USA. ifbielak@umich.edu
authors.forename: Lawrence F
authors.initials: LF
authors.lastname: Bielak
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Turner
authors.forename: Stanley S
authors.initials: SS
authors.lastname: Franklin
authors.forename: Patrick F
authors.initials: PF
authors.lastname: Sheedy
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Peyser
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D002114:Calcinosis / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D003324:Coronary Artery Disease / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000473:pathology* / Q000503:physiopathology*; D007407:Interviews as Topic; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D014463:Ultrasonography