title: Reference values for local arterial stiffness. Part A: carotid artery.
abstract: OBJECTIVE
  Non-invasive measures of common carotid artery properties, such as diameter and distension, and pulse pressure, have been widely used to determine carotid artery distensibility coefficient - a measure of carotid stiffness (stiffness ∼1/distensibility coefficient). Carotid stiffness has been associated with incident cardiovascular disease (CVD) and may therefore be a useful intermediate marker for CVD. We aimed to establish age and sex-specific reference intervals of carotid stiffness.
  
  
  METHODS
  We combined data on 22 708 individuals (age range 15-99 years, 54% men) from 24 research centres worldwide. Individuals without CVD and established cardiovascular risk factors constituted a healthy sub-population (n = 3601, 48% men) and were used to establish sex-specific equations for percentiles of carotid distensibility coefficient across age.
  
  
  RESULTS
  In the sub-population without CVD and treatment (n = 12 906, 52% men), carotid distensibility coefficient Z-scores based on these percentile equations were independently and negatively associated, in men and women, respectively, with diabetes {-0.28 [95% confidence interval (CI) -0.41; -0.15] and -0.27 (-0.43; -0.12)}, mean arterial pressure [-0.26 (-0.29; -0.24) and -0.32 (-0.35; -0.29)], total-to-high-density lipoprotein cholesterol ratio [-0.05 (-0.09; -0.02) and -0.05 (-0.11; 0.01)] and BMI [-0.06 (-0.09; -0.04) and -0.05 (-0.08; -0.02)], whereas these were positively associated with smoking [0.30 (0.24; 0.36) and 0.24 (0.18; 0.31)].
  
  
  CONCLUSIONS
  We estimated age and sex-specific percentiles of carotid stiffness in a healthy population and assessed the association between cardiovascular risk factors and carotid distensibility coefficient Z-scores, which enables comparison of carotid stiffness values between (patient) groups with different cardiovascular risk profiles, helping interpretation of such measures.
authors.affiliation: aDepartment of Internal Medicine bCARIM School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht cTop Institute Food and Nutrition, Wageningen, the Netherlands dHeymans Institute of Pharmacology, Research Unit of Clinical Pharmacology, Ghent University, Ghent, Belgium eDepartment of Clinical Epidemiology and Medical Technology Assessment (KEMTA) fDepartment of Biomedical Engineering, Maastricht University Medical Centre, Maastricht, the Netherlands gInstitute Biomedical Technology, iMinds Medical IT, Ghent University, Ghent, Belgium hDepartment of Pharmacology and INSERM U970, Hôpital Européen Georges Pompidou, Paris, France *A complete author list is included in the Appendix (Table A1, http://links.lww.com/HJH/A498).
authors.forename: Lian
authors.initials: L
authors.lastname: Engelen
authors.forename: Jelle
authors.initials: J
authors.lastname: Bossuyt
authors.forename: Isabel
authors.initials: I
authors.lastname: Ferreira
authors.forename: Luc M
authors.initials: LM
authors.lastname: van Bortel
authors.forename: Koen D
authors.initials: KD
authors.lastname: Reesink
authors.forename: Patrick
authors.initials: P
authors.lastname: Segers
authors.forename: Coen D
authors.initials: CD
authors.lastname: Stehouwer
authors.forename: Stéphane
authors.initials: S
authors.lastname: Laurent
authors.forename: Pierre
authors.initials: P
authors.lastname: Boutouyrie
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D059289:Vascular Stiffness / Q000502:physiology*; D055815:Young Adult