African American youth already prone to high-blood pressure are at a higher risk for cardiovascular disease if they are mentally stressed.
In a study released today, "Impaired stress induced pressure natriuresis clusters with reduced endothelial function in African American youth at risk of hypertension," researchers Eady, Kapuku and Harshfield tested ways to identify youth at risk for deteriorating endothelial function. Endothelial dysfunction, which restricts the way the arteries dilate and allow blood flows, has been observed in patients with coronary artery disease.
Fifty-two healthy African American adolescents, 15-18 years of age, participated in the study. They were given two hours of rest, one hour of stressful activity, followed by a restful recovery period of two hours. Blood pressure was taken every 15 minutes and urinary sodium excretion was assessed hourly. The researchers also assessed how well the arteries dilated during blood circulation. Known as endothelium-dependent arterial dilatation (EDAD), this function was measured using ultrasound technique.
For 31 of the youth, their response to stress showed normal sodium excretion but 21 of the youth had less sodium excretion (impaired natriuresis) than their counterparts. For those with impaired natriuresis, EDAD was lower than for those with normal natriuresis. Lower EDAD scores were linked with higher pre-stress sodium excretion, higher pre-stress diastolic blood pressure and greater increase of blood pressure during stress. In other words, higher sodium intake and higher blood pressure were associated to a reduced endothelial function, which is an early marker of cardiovascular disease.
"These results suggest that for some African American youth at-risk of high blood pressure, stress may also contribute to more rapidly declining endothelial function," stated Gaston Kapuku, MD, PhD, associate professor of pediatrics and cardiovascular scientist at Medical College of Georgia. "We will continue our study on EDAD to determine how we can address low EDAD in African American youth."
These scientific findings were presented today at the 21st International Interdisciplinary Conference on Hypertension and Related Cardiovascular Risk Factors in Ethnic Populations as Abstract 014. The abstract appears below. Additional conference information and news from the conference can be found at http://www.ishib.org/ISHIB2006.