Abstract 12214: Cardiorespiratory Fitness Lowers the Risk of Stroke in African-American Veterans

Abstract

Introduction: Stroke incidence is significantly higher in African-Americans (AA) than in any other racial group. Cardiorespiratory fitness (CRF) is associated with a more favorable cardiovascular health. The CRF-stroke incidence association has not been fully explored in AA patients. Hypothesis: We hypothesize that the CRF-stroke incidence association will be inverse and graded. Methods: From 1985 to 2014, we identified 13,511 AA (mean age: 58±11) with a normal response to an exercise tolerance test (ETT) and no prior history of stroke. We established five fitness categories based on age-stratified quintiles of peak metabolic equivalents (MET) achieved: Least-Fit (4.2±1.2 METs; n=2,708); Low-Fit (6.0±1.2; n=2,914); Moderate-Fit (7.9±1.0 METs; n=2,816); Fit (8.6±1.4 METs; n=2,903); and High-Fit (11.5±2.3 METs; n=2,170). Multivariable Cox model, adjusted for age, BMI, gender, cardiac risk factors, blood pressure, sleep apnea, alcohol dependence and medications, was used to estimate hazard ratios (HR) and 95% confidence intervals [CI], for incidence of stroke across fitness categories. The Least-fit category was used as the reference group. Results: During follow-up (median=11.3 years) 703 individuals (5.2%) developed stroke. The risk for stroke was 7% lower for each 1-MET increase in exercise capacity (HR=0.93, CI: 0.90-0.96; p<0.001). When considering fitness categories, stroke risk was lower by: 27% (HR=0.73; CI: 0.59-0.89) in the Low-Fit individuals; 34% (HR= 0.66; CI: 0.53-0.74) in the Moderate-Fit; 41% lower in the Fit (HR= 0.59; CI: 0.45-0.75) and 43% in High-Fit individuals (HR= 0.57; CI: 0.44-0.74). Conclusions: CRF was inversely related to stroke incidence in AA. The risk declined progressively with increasing CRF and was over 40% lower for individuals in the two highest fitness categories.