<p>This study aimed to elucidate the association between the body roundness index (BRI), an indicator of abdominal obesity, and the odds of developing psoriasis. We conducted a comprehensive, multi-ethnic cross-sectional analysis utilizing data from the National Health and Nutrition Examination Survey (NHANES). Height and weight measurements were obtained from the database, recorded by trained personnel using standardized equipment. In addition, demographic and clinical information was collected via questionnaires. The association between BRI and psoriasis odds was assessed using multivariable weighted logistic regression models, and the relationship was further visualized through restricted cubic spline (RCS) curves. Subgroup analyses were conducted to explore this association across different populations, and sensitivity analyses were performed using unweighted methods to validate the findings. The study encompassed 21,242 participants, of whom 562 were diagnosed with psoriasis. Comparative analyses of clinical and demographic characteristics between psoriasis and non-psoriasis groups revealed statistically significant differences. The weighted logistic regression analysis demonstrated a positive association between BRI and the occurrence of psoriasis, with BRI considered both as a continuous and a categorical variable. Specifically, each unit increase in BRI was associated with a 9% increase in the odds of psoriasis (95% confidence interval: 4% to 13%). The RCS curves indicated a progressive increase in psoriasis odds with rising BRI levels. Subgroup analyses consistently showed a significant positive correlation between BRI and psoriasis odds across diverse populations. The sensitivity analysis corroborated the main findings, underscoring the robustness of our conclusions. Our findings establish a significant and reliable positive association between BRI, a marker of abdominal obesity, and the odds of psoriasis across various populations.</p>