Abstract
<title>Abstract</title> <p> <bold>Background</bold> Red blood cell distribution width (RDW) has been widely associated with inflammation and metabolic disorders. However, its relationship with the visceral adiposity index (VAI) remains unexplored in adult populations. This study aimed to investigate the association between RDW and VAI using data from a nationally representative cohort. <bold>Methods</bold> We analyzed data from 14,568 adults aged 20 years and older who participated in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018, with complete RDW and VAI data. Linear regression analysis, curve fitting, threshold effect analysis, and subgroup analysis were employed to examine the relationship between RDW and VAI. <bold>Results</bold> Multivariate linear regression revealed a significant inverse association between RDW and VAI (β = -0.56; 95% confidence interval: -0.84 to -0.28). Subgroup analyses and interaction tests indicated that this inverse relationship was more pronounced in male hypertensive patients. A nonlinear approach incorporating smoothed curve modeling and threshold effect evaluation revealed an inflection point at RDW = 12.9%. <bold>Conclusions</bold> RDW is inversely associated with VAI, particularly in male hypertensive patients. The results indicate that RDW could be a valuable and cost-effective indicator for identifying metabolic dysfunction and visceral adiposity in high-risk populations. </p>