The Fitness Fatness Index Is Inversely Associated with Measures of Vascular Aging Derived from Blood Pressure in a Representative Sample of Adults in the United States

Purpose: Both low cardiorespiratory fitness (CRF) and obesity may hasten vascular aging and increase atherosclerotic cardiovascular disease (ASCVD) risk. This study explored the joint association of CRF and obesity with ASCVD risk using the fitness fatness index (FFI) and measures of vascular aging derived from blood pressure in a large sample of United States adults. Methods: Data from the 1999-2002 National Health and Nutrition Examination Survey were used (N=8,080 adults between the ages of 20-85 years, which is a weighted population equivalent of 174,277,151). The FFI was calculated as CRF divided by waist-to-height ratio. Measures of vascular aging included estimated pulse wave velocity (ePWV), pulse pressure (PP), and the vascular overload index (VOI), with ePWV being calculated from systolic and diastolic blood pressures and age while PP and VOI were calculated from blood pressure alone. Results: After full adjustment for age, sex, race/ethnicity, education, body mass index, smoking, physical activity, diabetes, hypertension, cardiovascular disease, high-density lipoprotein cholesterol, and total cholesterol, FFI was inversely associated with ePWV (b=-.10; 95% confidence interval [CI], -0.11 to -0.09; p0.001), PP (b=-.86; 95% CI, -1.03 to -0.68; p 0.001) and the VOI (b=-.74; 95% CI, -0.95 to -0.053; p 0.001). Conclusion: FFI is associated with lower ePWV, PP, and VOI in a nationally representative sample of adults. Maintaining higher CRF concomitant with lower body fat may minimize vascular load and contribute to healthy vascular aging. Conversely, lower fitness and higher fatness may contribute to early/accelerated vascular aging.