The methodology of the gold standard for measuring aortic stiffness, carotidefemoral pulse wave velocity (cfPWV), has been revised in respect to the choice of distance measure. In order to clarify whether increased aortic stiffness is present in obese children and adolescents we investigated cfPWV with the previous (cfPWV-subtracted) and a newly revised methodology (cfPWV-direct). Methods: In a cross-sectional design, 104 obese patients with age 10e18 years newly referred to the Children's

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... ty Clinic were compared to 50 healthy control individuals. CfPWV was measured non-invasively using the SphygmoCor device, while all distance measures were made with a calliper. Results: Opposite to the direct distance, the subtracted distance differed across study groups in relation to height (P < 0.006). CfPWV-subtracted was significantly higher for the obese (4.5 m/s CI: 4.4e4.6 vs. 4.3 m/s CI: 4.2e4.5, P Z 0.03), whereas cfPWV-direct was significantly lower (4.8 m/s CI: 4.7e4.9 vs. 5.1 m/s CI: 4.9e5.3, P Z 0.008). In multiple regression, being obese did Abbrevations: AIx, augmentation index; BMI, body mass index; BP, blood pressure; cfPWV, carotidefemoral pulse wave velocity; ICC, intraclass correlation coefficient; WC, waist circumference. Artery Research (2013) 7, 186e193 not significantly influence cfPWV-subtracted (b Z 0.126, CI: À0.04e0.29, NS) whereas it significantly reduced cfPWV-direct (b Z À0.34, CI: À0.53e0.15, P < 0.001), when adjusting for age, gender, mean arterial blood pressure and heart rate. Both groups had normal values of cfPWVsubtracted in respect to a European reference material. Conclusion: The distance measure of cfPWV-direct was associated similarly to height across study groups. Adjusted for main confounders, cfPWV-subtracted was equal whereas cfPWV-direct was reduced in obese compared to normal weighted children and adolescents.