DETERMINANTS OF ENDOTHELIUM-DEPENDENT FEMORAL-ARTERY VASODILATION IN YOUTH

Objective: Decreased endothelium-dependent arterial dilation to reacti ve hyperemia has been shown in adults to be associated with various ma nifestations of cardiovascular diseases and cardiovascular risk factor s. In a sample of children, we examined the relationships between flow -mediated femoral artery dilation and anthropometric, demographic, car diovascular, and serum lipid variables that have been associated with cardiovascular diseases, Method: Thirty-three asymptomatic, healthy 11 to 14 years olds were randomly selected from participants in a longit udinal cardiovascular health study, There were 17 boys and 16 girls; 2 1 whites and 12 blacks. Sixteen had documented family history of prema ture myocardial infarction (ie, less than or equal to 55 years of age) in first-degree relatives and 17 did not, Measurements included fasti ng lipids, anthropometrics, blood pressure and heart rate at rest and during supine exercise, postural change, and forehead cold stimulation . Femoral artery dilation to reactive hyperemia was measured via high resolution ultrasound, Results: Bivariate analyses indicated flow-medi ated dilation was negatively correlated with systolic pressure increas es to postural change, forehead cold stimulation and dynamic exercise, greater average skinfold thickness, and body fat via dual x-ray absor ptiometry and positively correlated with cardiovascular fitness (all p s<.05). Stepwise multiple regression revealed that cardiovascular fitn ess and systolic pressure reactivity to exercise significantly predict ed flow-mediated dilation accounting for 31% of the variance (p<.01). Conclusions: Decreased flow-mediated dilation is associated with decre ased cardiovascular fitness, increased systolic pressure reactivity to various stressors, and increased indices of body fatness in asymptoma tic youth. Further research is warranted to better understand early re lationships between this noninvasive measure of endothelial function a nd cardiovascular risk factors in youth.