Association of fitness with vascular intima-media thickness and elasticity in adolescence.
OBJECTIVES
Vascular intima-media thickness (IMT) and elasticity are surrogate markers of atherosclerosis. Data on the effect of cardiorespiratory fitness on these measures of vascular health in adolescence are scarce. The aim was to examine the association of fitness with aortic and carotid artery IMT and elasticity in adolescents.


METHODS
Aortic (n = 449) and carotid (n = 467) IMT and elasticity were measured ultrasonographically in 17-year-old adolescents participating in a prospective, longitudinal atherosclerosis prevention study (Special Turku Coronary Risk Factor Intervention Project). Distensibility and Young's elastic modulus (YEM) were used as measures of arterial elasticity. Cardiorespiratory fitness (maximum oxygen uptake, mL/kg/min) was measured with a maximal cycle ergometer test. Data on fitness were available for 341 of adolescents with aortic and 355 with carotid ultrasound measures.


RESULTS
Fitness was inversely associated with aortic IMT (β[SE] = -0.0029[0.0013]; P = .031) and YEM (β[SE] = -0.012[0.0053]; P = .025) after adjusting for gender, physical activity, high-density lipoprotein/total cholesterol, triglycerides, high-sensitivity C-reactive protein, homeostasis model of assessment-insulin resistance, BMI, systolic blood pressure, and smoking. Risk of having low aortic distensibility (≤10th percentile) decreased with increasing fitness (odds ratio = 0.89, 95% confidence interval 0.82-0.98); P = .014). The increase in aortic IMT and YEM between ages 11 and 17 years was smaller in adolescents who were fit at age 17 compared with adolescents who had the lowest fitness level (P for IMT = .015, P for YEM = .0072). Fitness was not associated with carotid IMT or elasticity. Lifestyle counseling given in the Special Turku Coronary Risk Factor Intervention Project was not associated with fitness.


CONCLUSIONS
Fitness was favorably associated with aortic IMT and elasticity in adolescents. No association of fitness with the respective carotid indices was found. These data suggest that fitness in part enhances vascular health in healthy adolescents.