PP.13.01] ASSOCIATION BETWEEN NECK CIRCUMFERENCE, AORTIC AND CAROTID STIFFNESS IN HEALTHY ADOLECENTS THE MACISTE STUDY

Abstract

Objective: Introduction: Obesity has a negative impact on arterial distensibility. Neck circumference (NC) is a marker of upper body adiposity and is linked to unfavourable metabolic profile among young subjects. The association between NC and arterial stiffness is unknown. We evaluated the association between NC and other measures of adiposity, with carotid-femoral pulse wave velocity (cf-PWV) and carotid stiffness (CS) in healthy adolescents. Design and method: Methods: 431 individuals (mean age 16.9 ± 1.4y, SBP/DBP 124/67 ± 11/7 mmHg) attending the Liceo Donatelli High School in Terni, Italy, were evaluated. cf-PWV was measured with applanation tonometry (SphygmoCor device, subtracted distance). CS was measured with Carotid Studio (Quipu): a contour tracking algorithm was applied to B-mode longitudinal scans of common carotid artery to obtain diameter changes, stroke change in lumen area (δA) and lumen area (A). The cross-sectional distensibility coefficient (DC = δA /(A*PP)) was converted (Bramwell-Hill equation) into a carotid stiffness parameter (CS = (DC*ρ)-1/2, ρ=blood density) with same measurement units of PWV. Carotid waveform was calibrated to brachial MAP/DBP. Brachial MAP was derived from brachial tonometry calibrated to brachial SBP/DBP. Results: Average NC was 33 ± 3 cm, average cf-PWV 4.9 ± 0.8 m/s, average CS 4.3 ± 0.6 m/s. NC, as well as other measures of adiposity (BMI, BMI z-score, waist and hip circumferences, waist-hip ratio, waist-height ratio), showed some degrees of association with both cf-PWV and CS (Table). The association between NC and CS was the only association which remained significant after adjustement for age, sex and MAP (partial R = 0.13, p < 0.01), and also after further adjustment for BMI (partial R = 0.10, p = 0.03).Conclusions: In adolescents, NC and other measures of global and local adiposity showed significant associations with cf-PWV and CS. The association between NC and CS was independent from age, sex, MAP and BMI. Both local and systemic factors may be involved in explaining this relationship. NC may help in identifying adolescents with increased CS.