Mediating Role of BMI in the Association Between Obstructive Sleep Apnea and Nonalcoholic Fatty Liver Disease: A Cross-Sectional Mediation Analysis.

OBJECTIVE

To investigate the mediating role of body mass index (BMI) in the association between obstructive sleep apnea (OSA) and nonalcoholic fatty liver disease (NAFLD).

METHODS

In this cross-sectional study, 445 adult patients diagnosed with OSA at Zigong Fourth People's Hospital (2022-2024) were initially enrolled. After applying inclusion/exclusion criteria, 309 participants were included. Demographic characteristics and clinical parameters were collected. Correlation analysis and structural equation modeling (SEM) were utilized to assess BMI's mediation effect between OSA and NAFLD.

RESULTS

Correlation analyses revealed significant positive associations of BMI with both OSA (r = 0.296, p < 0.001) and NAFLD (r = 0.225, p < 0.001), while OSA and NAFLD were directly correlated (r = 0.199, p < 0.001). Mediation analysis demonstrated a significant indirect effect of OSA on NAFLD through BMI (β = 0.044, 95% CI: 0.004-0.084), accounting for 22.5% of the total effect. These findings remained robust after adjusting for covariates including sex, age, smoking status, hypertension, and diabetes mellitus.

CONCLUSION

BMI serves as a critical mediator in the OSA-NAFLD relationship, suggesting that integrated weight management strategies should be incorporated into OSA therapy to reduce hepatic risk.