Association Between Obesity Indices, Insulin Resistance Markers, and Osteoarthritis in Middle-Aged and Elderly Chinese Adults

Suyao ZhangZhen JiangHuayuan LiaoHuwei BianJunan ZhouHaibo WangTao Jiang^*

• Changzhou Hospital Affiliated to Nanjing University of Chinese Medicine, Changzhou, China

Background: Previous studies have indicated an association between osteoarthritis (OA), obesity, and insulin resistance (IR). However, current literature lacks sufficient clinical data to fully elucidate the relationship between obesity indices, insulin resistance surrogates, and OA in China's middle-aged and elderly population. This study aims to investigate the correlation between obesity indices (body fat percentage [BFP], lipid accumulation product [LAP], body mass index [BMI], waist-to-height ratio [WHtR]), insulin resistance surrogates (triglyceride-glucose [TyG] index and its derivatives: TyG with waist circumference [TyG-WC], TyG with BMI [TyG-BMI], TyG-WHtR), and OA risk, and evaluate the diagnostic efficacy of these indices for OA. Methods: A cross-sectional study was conducted based on data from the China Health and Retirement Longitudinal Study (CHARLS). Multivariable logistic and Cox regression models, restricted cubic splines, interaction terms, subgroup analyses, and receiver operating characteristic (ROC) curves were used to evaluate the relationships between obesity indices, IR surrogates, and OA risk in the middle-aged and elderly Chinese population. Results: In this study, 10,457 participants were included, of whom 3,667 were diagnosed with OA. In fully adjusted models, all indices as continuous variables were positively associated with OA risk (all p < 0.05): BFP (95% CI: 1.02–1.04), LAP (95% CI: 1.04–1.15), BMI (95% CI: 1.02– 1.05), WHtR (95% CI: 1.10–1.21), TyG (95% CI: 1.02–1.20), TyG-WC (95% CI: 1.06–1.18), TyG-BMI (95% CI: 1.10–1.22), and TyG-WHtR (95% CI: 1.14–1.32). ROC analysis indicated TyG-WHtR had the greatest predictive ability for OA risk (AUC = 0.680). A multivariable Cox regression analysis of TyG-WHtR in 5,718 participants, among whom 1,827 developed OA during a median follow-up of 108 months, showed each one-unit increase in TyG-WHtR was associated with a 20% higher risk of OA (95% CI: 1.11–1.31). Trend tests revealed a significant dose– response relationship (p < 0.05). Conclusion: Obesity-related indicators and insulin resistance surrogates are significantly associated with OA risk. Among these, TyG-WHtR demonstrates the strongest predictive performance, suggesting its potential as an early screening tool for OA. This study highlights obesity and insulin resistance as modifiable risk factors, providing a basis for the early prevention and control of OA.