Association between the uric acid-to-high-density cholesterol ratio (UHR) and obstructive sleep apnea: mediation by...

Emerging evidence highlights interactions between obstructive sleep apnea (OSA), lipid metabolism, and inflammation, yet the associations bridging inflammatory processes to metabolic dysregulation in OSA remain poorly defined. This study evaluates the uric acid-to-high-density lipoprotein cholesterol ratio (UHR)-a novel composite metabolic-lipid biomarker-and C-reactive protein (CRP), a classical inflammatory marker, to elucidate their associations with OSA and potential mediating pathways.

Using data from the National Health and Nutrition Examination Survey (NHANES), we performed weighted multivariable logistic regression to examine associations of UHR and CRP with OSA. Nonlinear relationships were assessed via restricted cubic splines (RCS), and mediation analysis quantified CRP's role in linking UHR to OSA. Subgroup and sensitivity analyses tested result robustness.

Among 14,815 participants (7538 OSA cases), higher UHR levels showed a positive correlation with OSA prevalence in fully adjusted cross-sectional analyses. Specifically, the highest vs. lowest UHR quartile was correlated with 31% higher odds of OSA (OR = 1.31, 95% CI 1.15-1.49, P < 0.001). A similar pattern was observed for CRP, where elevated levels corresponded to 32% greater odds of OSA (OR = 1.32, 95% CI 1.18-1.47, P < 0.001). RCS analysis revealed a nonlinear dose-response relationship between UHR and OSA (P for nonlinear < 0.001), characterized by an inverted L-shaped curve with steeper risk elevation at lower UHR values and stabilization at higher levels. CRP accounted for 17.7% of the observed association between UHR and OSA (P < 0.001). Stratified and sensitivity analyses confirmed consistency across subgroups.

Elevated UHR levels were independently associated with OSA risk in this cross-sectional cohort, highlighting its potential as a clinical biomarker. The partial mediation role of CRP may reflect underlying pathways linking metabolic dysregulation and inflammation in OSA.