Correlation Analysis Between Inflammatory Biomarkers and Dizziness: A Cross-Sectional Analysis Based on NHANES 1999-2004

Background: Dizziness is a common symptom with diverse etiologies, and its prevalence increases with age. Emerging evidence indicates that systemic inflammatory processes might contribute to the development of dizziness. Nevertheless, the association between dizziness and integrated hematologic inflammatory markers has not been thoroughly investigated. Objective: This study aims to assess the relationship between inflammatory markers and dizziness. Methods: This population-based cross-sectional analysis utilized data from the National Health and Nutrition Examination Survey (NHANES) conducted between 1999 and 2004. The study population consisted of 6,393 individuals aged over 40 years old. Seven inflammation-related biomarkers included monocyte-to-lymphocyte ratio (MLR), systemic inflammation response index (SIRI), C-reactive protein-to-albumin ratio (CAR), aggregate index of systemic inflammation (AISI), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio(PLR), and systemic immune-inflammation index (SII), which were computed from standard complete blood counts. Analytical approaches included weighted logistic regression, restricted cubic spline (RCS) models, threshold effect evaluation, subgroup stratification, and receiver operating characteristic (ROC) curve analyses to determine the relationship between these biomarkers and self-reported dizziness. Results: After adjusting for potential confounders, elevated levels of MLR, SIRI, AISI, and CAR were significantly associated with increased odds of dizziness. RCS and threshold effect analysis revealed a significant non-linear relationship between SIRI and dizziness, with a significant inflection point at 1.2526. Subgroup analyses indicated stronger associations among females, non-smokers, and individuals with higher educational attainment. Among all markers, SIRI demonstrated the highest area under the ROC curve (AUC = 0.5532), although overall predictive performance remained modest. Conclusion: Several CBC-derived inflammatory biomarkers (MLR, SIRI, and AISI) were independently associated with dizziness in a general adult population. These findings support the involvement of systemic inflammation in dizziness and suggest that such biomarkers may serve as adjunctive tools for risk identification. Further longitudinal studies are needed to clarify causality and underlying mechanisms.