Association between visceral fat area and heart rate variability in high altitude migrants with OSA: the mediating effect of insulin resistance

Abstract Objective This study was conducted to investigate the association between visceral fat area (VFA) and heart rate variability (HRV) in high-altitude migrants with obstructive sleep apnea (OSA). Method We conducted a cross-sectional study comprising 152 OSA participants from 2022 to 2024. We employed multivariable linear regression to further elucidate the association between VFA and HRV. Mediation analysis was utilized to investigate the indirect effects of insulin resistance and white blood cell counts on this relationship. Sensitivity analysis assessed the robustness of the results. To explore the influence of gender on the results, we conducted gender-specific subgroup analyses and interaction tests. Results Multivariable regression analysis revealed that for every 20-unit increase in VFA, there were significant reductions in SDNN (-4.00, 95% CI: -5.90, -2.11), SDANN (-3.51, 95% CI: -5.43, -1.60), SDNN index (-1.35, 95% CI: -2.13, -0.56), rMSSD (-0.92, 95% CI: -1.51, -0.33), and pNN50 (-0.58, 95% CI: -0.99, -0.17). Additionally, a significant positive association was found between VFA and the low-frequency/high-frequency ratio (LF/HF ratio) (0.25, 95% CI: 0.11, 0.39). Mediation analysis indicated a significant mediating effect of HOMA-IR on the VFA-HRV association, with proportions of 20.32%, 18.76%, and 26.23% for SDNN index, rMSSD, and LF/HF ratio, respectively. The mediating effect based on white blood cell count did not reach statistical significance. There was no gender difference in the association between VFA and HRV. The sensitivity analysis indicated that the findings remained robust. Conclusion Our findings indicated that visceral fat serves as a significant determinant of cardiovascular health among OSA patients residing at high altitudes and may represent a viable target for intervention and preventive strategies.