Abstract
PURPOSE: Obstructive sleep apnea (OSA) contributes to non-alcoholic fatty liver disease (NAFLD) via pathways involving insulin resistance (IR). The triglyceride-glucose (TyG) index, a widely used marker of IR, is associated with both OSA and NAFLD. However, the role of the TyG index in linking OSA to NAFLD remains underexplored. PATIENTS AND METHODS: This study analyzed data from two cross-sectional studies: 920 participants from the Fifth Affiliated Hospital of Sun Yat-sen University and 1,603 participants from NHANES 2005-2008. Mediation analysis assessed the TyG index's role in the OSA-NAFLD relationship. Weighted multivariable logistic regression and restricted cubic spline (RCS) regression explored the association between the TyG index and NAFLD in patients with OSA. RESULTS: Mediation analysis showed the TyG index mediated the OSA-NAFLD association, accounting for 35.33% and 20.06% in Chinese and American participants, respectively (P < 0.001). Logistic regression revealed that higher TyG index values were significantly associated with increased NAFLD risk in patients with OSA, with ORs of 2.32 (95% CI: 1.78-3.07) for Chinese and 6.80 (95% CI: 4.42-10.45) for American participants (P < 0.001). RCS regression showed a linear increase in NAFLD risk with higher TyG index values in patients with OSA. CONCLUSION: The TyG index significantly mediates the OSA-NAFLD relationship. Elevated TyG index values are significantly associated with NAFLD risk in patients with OSA. The TyG index is a biologically meaningful and effective biomarker of IR in the association between OSA and NAFLD, with potential for early identification of NAFLD in patients with OSA.