Purpose <p>Cardiovascular disease is among the most common diseases in the United States; however, relationships between obstructive sleep apnea (OSA), obesity, and cardiovascular health are not fully understood. This study aimed to examine differences in OSA severity and cardiovascular health indices across body mass index (BMI) classifications, and to investigate associations among OSA, BMI, and arterial stiffness in a sample of adults from the southeastern United States.</p> Methods <p>This analysis is part of the ongoing <i>Short Sleep Undermines Cardiometabolic Health-Public Health Observational Study (SLUMBRx-PONS)</i> study. Data included 75 adults assessed for anthropometrics, OSA severity, quantified via apnea-hypopnea index (AHI), and noninvasive cardiovascular health indices including resting mean arterial pressure (MAP), carotid-femoral pulse wave velocity (cfPWV), and augmentation index (AIx75).</p> Results <p>Compared to individuals at normal weight, adults with obesity presented with significantly higher AHI, MAP, cfPWV, and AIx75 values. While AHI and cfPWV were not directly associated, after adjusting for sex and MAP, we found a BMI-mediated negative association between age and cfPWV, which was strongest among younger adults with elevated BMI. Additionally, adjusting for age and MAP, AHI was positively associated with AIx75, also mediated by BMI, with the greatest effect observed at higher BMI levels.</p> Conclusion <p>These results suggest that obesity is a key contributor to poor cardiovascular health in the southeastern United States. Moreover, the relationship between OSA and arterial stiffness may be BMI-dependent and varies by measurement selection. Obesity and measurement selection should be primary considerations for arterial stiffness in cardiovascular risk assessment.</p>