Association between triglyceride levels and rheumatoid arthritis prevalence in women: a cross-sectional study of NHANES (1999-2018)

Background Rheumatoid arthritis (RA) is a chronic autoimmune disease with a higher prevalence in women. Triglycerides, key indicators of lipid metabolism, are linked to inflammation and metabolic disorders, both contributing to RA pathogenesis. However, the association between triglyceride levels and RA prevalence in women remains unclear. This study analyzes this association using NHANES (1999-2018) data to provide evidence for prevention and personalized intervention strategies. Methods This study utilized data from the National Health and Nutrition Examination Survey (NHANES) spanning 1999 to 2018. It included 10,728 female participants, of whom 639 were diagnosed with RA. Triglyceride levels were categorized into four quartiles (Q1 to Q4), and multivariable logistic regression models were used to analyze the association between triglyceride levels and RA prevalence in women. Restricted cubic spline (RCS) analyses were performed to evaluate the potential nonlinear association between triglyceride levels and RA prevalence. Subgroup and interaction analyses were conducted to further investigate the association across different populations. Results Among the 639 RA patients, higher triglyceride levels were significantly positively associated with RA prevalence in women. In the unadjusted model, elevated triglyceride levels were significantly associated with an increased RA prevalence (OR: 1.30, 95% CI: 1.04-1.61, P = 0.019). This association remained significant in the adjusted model, with the highest quartile showing a substantially higher risk compared to the lowest quartile (OR: 2.46, 95% CI: 1.22-4.95, P for trend = 0.04). RCS analyses indicated a linear association between triglyceride levels and RA prevalence (P for nonlinearity = 0.19). Subgroup analyses revealed consistent trends across various subgroups, with no significant interactions observed (all interaction P-values > 0.05). Conclusion This study demonstrates a significant positive association between elevated triglyceride levels and RA prevalence in women, with a linear trend observed in this association. Future research should further investigate the role of triglyceride levels in the pathogenesis of RA and explore potential intervention pathways.