title: Impact of central obesity on the estimation of carotid-femoral pulse wave velocity.
abstract: BACKGROUND
  Studies have found that central obesity is associated with higher carotid-femoral pulse wave velocity (PWV). However, traveled distance (TD) measured over the body surface can be substantially overestimated with wider waist circumference (WC). We sought to investigate whether central obesity biases the estimation of PWV and whether this bias explains the association between PWV and different measures of adiposity.
  
  
  METHODS
  Seven hundred eleven participants (49.5% men) from the Baltimore Longitudinal Study of Aging with PWV, anthropometrics, and quantification of different fat depots by computed tomography and dual x-ray absorptiometry were included. TD and relative PWV were estimated with a tape measure over the body surface or linear distances taken from radiological images, unaffected by obesity.
  
  
  RESULTS
  A significant association was found between wider WC and a greater difference between the 2 TD measurements and their respective PWV in both sexes (r ≥ 0.34; P < 0.001). This overestimation bias appeared to be generally higher in women than men (0.27 m/sec for each unit increase in WC; P < 0.0001). When TD estimated over the body surface was used to calculate PWV, greater WC, total body fat, subcutaneous fat, and visceral fat were all associated with higher PWV (P < 0.05 for all). However, when PWV was calculated using TD estimated from radiological images or body height, only the association with visceral fat held significant.
  
  
  CONCLUSIONS
  When TD is measured over the body surface, the role of obesity on PWV is substantially overestimated. After accounting for this bias, PWV was still independently associated with visceral fat but not with other measures of adiposity, confirming its contribution to arterial stiffening.
authors.forename: Marco
authors.initials: M
authors.lastname: Canepa
authors.affiliation: Longitudinal Studies Section, Translational Gerontology Branch, National Institute of Aging, National Institutes of Health, Baltimore, Maryland; Laboratory of Cardiovascular Sciences, Human Cardiovascular Studies Unit, National Institute of Aging, National Institutes of Health, Baltimore, Maryland; Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland. majd.alghatrif@nih.gov.
authors.forename: Majd
authors.initials: M
authors.lastname: AlGhatrif
authors.affiliation: Department of Internal Medicine, University of Genova, Genova, Italy;
authors.forename: Gabriele
authors.initials: G
authors.lastname: Pestelli
authors.affiliation: Laboratory of Cardiovascular Sciences, Human Cardiovascular Studies Unit, National Institute of Aging, National Institutes of Health, Baltimore, Maryland;
authors.forename: Rohan
authors.initials: R
authors.lastname: Kankaria
authors.affiliation: Longitudinal Studies Section, Translational Gerontology Branch, National Institute of Aging, National Institutes of Health, Baltimore, Maryland;
authors.forename: Sokratis
authors.initials: S
authors.lastname: Makrogiannis
authors.affiliation: Longitudinal Studies Section, Translational Gerontology Branch, National Institute of Aging, National Institutes of Health, Baltimore, Maryland; Laboratory of Cardiovascular Sciences, Human Cardiovascular Studies Unit, National Institute of Aging, National Institutes of Health, Baltimore, Maryland;
authors.forename: James B
authors.initials: JB
authors.lastname: Strait
authors.affiliation: Department of Internal Medicine, University of Genova, Genova, Italy;
authors.forename: Claudio
authors.initials: C
authors.lastname: Brunelli
authors.affiliation: Laboratory of Cardiovascular Sciences, Human Cardiovascular Studies Unit, National Institute of Aging, National Institutes of Health, Baltimore, Maryland;
authors.forename: Edward G
authors.initials: EG
authors.lastname: Lakatta
authors.affiliation: Longitudinal Studies Section, Translational Gerontology Branch, National Institute of Aging, National Institutes of Health, Baltimore, Maryland;
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
mesh_terms: D015502:Absorptiometry, Photon; D050154:Adiposity; D000368:Aged; D000369:Aged, 80 and over; D015142:Baltimore; D015982:Bias; D001830:Body Surface Area; D002339:Carotid Arteries / Q000503:physiopathology*; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D056128:Obesity, Abdominal / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D063177:Pulse Wave Analysis; D015203:Reproducibility of Results; D012737:Sex Factors; D014057:Tomography, X-Ray Computed; D059289:Vascular Stiffness; D055105:Waist Circumference
keywords: arterial stiffness; blood pressure; hypertension; obesity; pulse wave velocity; travel distance; visceral fat; waist circumference.