Juntao Wu,1,* Haohong Lai,2,* Jiyuan Yin,2,* Shan Zhu,1 Haidi Yang,2 Haiyu Hong1 

1Department of Otolaryngology, the Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, Guangdong, People’s Republic of China; 2Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Haidi Yang, Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107th Yanjiangxi Road, Guangzhou, Guangdong, 510120, People’s Republic of China, Email yanghd@mail.sysu.edu.cn Haiyu Hong, Department of Otolaryngology, the Fifth Affiliated Hospital of Sun Yat-sen University, 52th Meihua East Road, Zhuhai, Guangdong, 519000, People’s Republic of China, Email honghy@sysu.edu.cn

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.

Keywords: insulin resistance, mediation analysis, non-alcoholic fatty liver disease, obstructive sleep apnea, triglyceride-glucose index