Carotid stiffness, extra-media thickness and visceral adiposity in young adults

Background and aims Carotid extra-media thickness (EMT) encompasses arterial adventitia and perivascular adipose tissue (PAT). Adventitial remodeling and PAT may contribute independently to functional (stiffness) and structural (remodeling) changes in artery wall properties. Visceral adiposity may contribute to PAT, thereby affecting artery stiffness. We investigated the relationships between carotid artery stiffness, EMT, and visceral adiposity in young, healthy individuals. Methods 135 healthy males (20 ± 2 yr, body mass index [BMI] 24.8 ± 3.3 kg/m²) underwent anthropometric and vascular measures on two separate days. Visceral adiposity was assessed using waist circumference and sagittal abdominal diameter (SAD). Brachial and carotid systolic, diastolic, and pulsatile (PP) blood pressures were assessed using an oscillometric cuff and applanation tonometry, respectively. Carotid intima-media thickness (IMT) and EMT were assessed using Doppler ultrasound. Carotid artery stiffness was calculated as β-stiffness and calibrated to carotid pressures. Results Separate stepwise multiple regression models demonstrated that carotid PP (β = 0.205) and EMT (β = 0.267) accounted for 12.6% of variance in β-stiffness, while carotid PP (β = 0.195) and SAD (β = 0.226) accounted for 10.5% of variance in EMT (p < 0.05). Mediation analyses revealed carotid PP partially mediated the relationship between a) EMT and β-stiffness, and b) SAD and EMT (p < 0.05). Conclusions Carotid PP and EMT, but not IMT, are related to carotid β-stiffness. Carotid PP and visceral adiposity (SAD) are related to EMT. Carotid PP partially mediates the association between a) EMT and carotid β-stiffness, and b) SAD and EMT. Our findings suggest visceral adiposity may detrimentally affect subclinical markers of cardiovascular disease risk (carotid PP, EMT) and contribute to artery stiffness.