Association between CTI and various triglyceride-glucose obesity-derived indices with arthritis: a cross-sectional analysis based on the NHANES database

BACKGROUND: Arthritis is jointly influenced by IR and inflammation, and the CTI is recognized as a novel marker for the comprehensive evaluation of inflammation and IR. Our study aimed to investigate the association between CTI and arthritis and to compare the differences in the TyG index and obesity indicators (including the TyG-BMI, TyG-WC, and TyG-WHtR) with respect to arthritis occurrence. METHODS: Our cross-sectional study utilized data from the NHANES, which was conducted between 2001 and 2010. Arthritis diagnosis relies on self-reported confirmation by a physician. Weighted logistic regression models were used to examine the associations between CTI, TyG, and obesity-derived indicators and arthritis, and weighted RCS models were applied to explore nonlinear effects. Furthermore, threshold effect analysis, subgroup analyses, interaction tests, and ROC curve analyses were performed. RESULTS: The results indicated that after full adjustment for confounders, the CTI was positively associated with arthritis regardless of whether it was treated as a continuous or categorical variable (P < 0.05). TyG, TyG-BMI, TyG-WC, and TyG-WHtR were positively associated with arthritis. Notably, when treated as categorical variables, the associations between TyG, TyG-BMI, TyG-WC, and TyG-WHtR and arthritis were positive, but Q2 was not statistically significant (P > 0.05). Except for TyG, RCS regression analysis and subgroup analysis consistently confirmed positive associations. Threshold effect analysis indicates that the associations of CTI and TyG with arthritis exhibit significant threshold effects. The TyG-WHtR showed the best diagnostic efficacy (AUC = 0.629). CONCLUSIONS: CTI, TyG-BMI, TyG-WC, and TyG-WHtR are all positively associated with the occurrence of arthritis, among which TyG-WHtR shows a stronger predictive ability. CTI has the potential to become an effective biomarker for the early identification of arthritis risk and the improvement of patient prognosis in young adults.