Abstract
BACKGROUND: A well-known global public health issue, osteoarthritis (OA) primarily affects the elderly. Although the etiology of OA remains unknown, immune and inflammatory factors are considered nonnegligible risk factors. This study investigated the association between the systemic immune-inflammatory index (SII) and the risk of OA. METHODS: Based on data from the National Health and Nutrition Examination Survey (NHANES), laboratory testing, basic information, and questionnaires were collected for cross-sectional analysis from a total of 15,317 adults during 2013-2018. In this study, the exposure variable was systemic inflammatory status as defined by SII, and the outcome was OA. Due to the complex survey design and sample weighting, we employed multiple logistic regression models and stratified analyses to evaluate the association between SII and OA. In addition, using an interaction test, we examined the relationship between SII, OA, and other variables. RESULTS: This study included a total of 15,317 participants, of whom 2207 were diagnosed with OA. Compared with the non-OA group, participants in the OA group had a significantly higher SII level. After adjusting for all covariates, log SII was positively associated with OA prevalence (OR = 1.27, 95% CI: 1.02, 1.59, P = 0.0353). Participants in the fourth SII quartile had a significantly higher OA prevalence than those in the first quartile (OR = 1.18, 95% CI: 1.00, 1.39, P = 0.0454). Subgroup analyses further confirmed the robustness of this positive association. CONCLUSION: Our study demonstrated that SII was associated with the risk of OA, suggesting a complex correlation between immunity and inflammation in OA. SII may serve as a useful predictor of OA and offer new insights into the diagnosis and management of the condition. Key Points • Elevated systemic immune-inflammatory index (SII) is significantly associated with a higher prevalence of osteoarthritis in a large, representative US adult population. • This positive association persists after comprehensive adjustment for potential confounders and across diverse population subgroups. • SII, as a novel and integrated biomarker, may offer valuable insights for the prediction and management of osteoarthritis.