Abstract 8579: Age Related Change in Aortic Stiffness in the Thoracic and Abdominal Aorta Among African Americans: The Jackson Heart Study

Abstract

Introduction : Age-related stiffening of the aorta is associated with increased aortic wall thickness (WT) in whites, but this relationship has not been clearly demonstrated in African Americans. We sought to determine this relationship in the Jackson Heart Study (JHS), a community-based prospective study of cardiovascular disease among 5,301 African Americans in the Jackson, Mississippi area. Hypothesis : Thoracic and abdominal measures of aortic pulse wave velocity (PWV), a measure of aortic stiffness, correlate with age related increases in WT in African Americans. Methods and Results : Beginning in 2009 (JHS Visit 3), 229 (67% women) consecutively recruited participants, aged 62+10 (39-87) years (89% hypertension, 39% diabetes, and 8% current smokers) underwent magnetic resonance imaging (MRI) measures of PWV and WT in the ascending and the descending thoracic aorta (aTA, dTA), and the abdominal aorta (AA). We determined the association between regional PWV and WT, age, gender, systolic blood pressure, body mass index, hemoglobin A1c, triglyceride, and high-density lipoprotein in a multivariable model. With age, regional PWV increased in the aTA and dTA (p<0.0001 for both), but not the AA (p=0.09; Figure 1); a 10 year increase in age corresponded to a 26%, 21% and 5.7% increase in PWV in the aTA, dTA and AA, respectively. The mean WT was 3.05+0.71 mm, 3.02+0.81 mm, and 2.04+ 0.78 mm in the aTA, dTA, and AA, respectively. After controlling for all variables in the model above, PWV showed a strong inverse relationship to WT: a 1% increase in WT was associated with a 0.26% decrease in PWV (p< 0.0001); this was true independent of the aortic region (p=0.08). Conclusion : Regional PWV increases with age in African Americans, but unlike whites, is inversely related to aortic WT. These data suggest that age-related stiffening of the aorta in African Americans may be related to factors that operate independent of wall thickness.