Background: increase in body mass index is accompanied by metabolic alterations but also by increased stroke volume (SV). Therefore, associated changes in vascular structure and function can not reflect only preclinical atherosclerosis but physiologic adaptation to body composition-related hemodynamic changes.

To evaluate the relationships between body composition and arterial structure and function without the influence of atherosclerotic risk factors, we assessed carotid intima-media thickness (IMT), luminal diameter (LD), wave speed (WS) and local pulse pressure (cPP)by radio-frequency based ultrasound (QIMT® and QAS®, Esaote), in 80 healthy children-adolescents with wide range of age (8–16 years) and BMI (15–40 kg/m2). Body composition was assessed by bioimpedance, visceral fat (VF) by ultrasound, and SV by Doppler. Plasma lipids, glucose and insulin were determined.

Results: body weight (BW) and fat free mass (FFM) were related to IMT (r=0.61 and 0.50), LD (r=0.54 and 0.53), WS (r=0.43 and 0.56) and cPP (r=0.36 and 0.49); fat mass (FM) was related to IMT and LD (r=0.40 and 0.29), and VF to IMT (r=0.41). SV was more strongly related to FFM than to FM (r=0.70 and 0.24). In multivariate models, IMT was determined by BW and triglycerides (R2=0.44), LD by BW and male sex (R2=0.37), WS by FFM and systolic BP (R2=0.39), cPP by FFM (R2=0.24). When SV was included into the models, it replaced FFM in model of cPP. Conclusion: adiposity-related changes in carotid function are depending on FFM-related increase in SV. Changes in carotid geometry also reflect an increase in body fat and plasma lipids.