Abstract 268: Vascular Dysfunction in High BMI Black College Football Players

Abstract

Background: Former football players (FP) who competed with BMI > 30 have high rates of atherosclerosis and early mortality (28% by age 50). FP are disproportionately black, a group predisposed to hypertension and atherosclerosis. Hypothesis: Positive energy balance and oxidative stress lead to vascular dysfunction in black FP. Methods: High BMI college FP (n=33) underwent metabolic and vascular testing at the Vanderbilt Medical Center during the offseason training program. Endothelial function was tested using flow-mediated dilation (FMD) of the brachial artery. Arterial elasticity and vascular resistance were tested using a calibrated tonometer. Regression was performed using least squares on Stat, version 12. Results: Elevated blood pressure (EBP) (SBP > 130) was common in both black (n = 14) and white (n = 19) athletes (78% vs 63%, p = .34). Black players had significantly higher systemic vascular resistance and lower arterial elasticity. However, they had significantly better lipid profiles and body composition, and comparable insulin resistance assessed by HOMA. In black FP, EBP was associated with positive energy balance (4.3 kg gained during six weeks from enrollment to clinic visit vs. 0.7 kg, p = .05). Daily caloric intake predicted endothelial function as measured by flow mediated vasodilation (FMD) (r=.76, p=.001). Caloric intake and oxidative stress (F2-isoprostanes) trended to inversely correlate with larger artery elasticity (r=.40, p=.09 and r=.41, p=.09, respectively). HOMA did not predict FMD (r < .01, p = .56). Respiratory quotient (RQ) correlated with f2-isoprostanes (r=.53, p=.02), suggesting a link between mitochondrial dysfunction and oxidative stress. Conclusion: High BMI black FP suffer from vascular dysfunction, possibly due to oxidative stress from overfeeding. This correlates with studies of non-athlete adult population, but differs notably in being independent of insulin resistance. A larger, longitudinal study is needed to establish a link between overfeeding, vascular dysfunction and early cardiovascular morbidity and mortality in high BMI black athletes. The role of oxidative stress and selective use of nitric oxide donor drugs in black athletes should be explored.