Plasma β‐Endorphin and Neuropeptide Y as Candidate Biomarkers for Predicting Obstructive Sleep Apnea Syndrome: A Preliminary Study

Background and Objective: Given the involvement of neuropeptides in the pathophysiology of obstructive sleep apnea syndrome (OSAS), this study investigated the associations between plasma levels of β‐endorphin (β‐EP) and neuropeptide Y (NPY) and OSAS severity and evaluated their potential as predictive biomarkers. Methods: A total of 48 snoring patients undergoing polysomnography (PSG) were categorized into non‐OSAS, mild, moderate, and severe OSAS groups ( n = 12 per group) based on the apnea–hypopnea index (AHI). Plasma levels of β‐EP and NPY were measured using ELISA. Statistical analyses included one‐way ANOVA, Spearman’s correlation, and receiver operating characteristic (ROC) curve analysis to assess predictive performance. Results: Plasma β‐EP levels exhibited significant elevation in moderate ( p = 0.003) and severe OSAS groups ( p = 0.032) compared to the non‐OSAS group. Notably, NPY levels demonstrated marked differences across all OSAS severity groups ( p < 0.01), with significantly higher concentrations observed in mild, moderate, and severe OSAS patients versus non‐OSAS controls ( p < 0.01). A progressive increase in NPY levels was observed with advancing OSAS severity, accompanied by statistically significant intergroup differences ( p < 0.01). Correlation analyses revealed strong positive associations between NPY levels and both BMI ( p < 0.0001) and AHI ( p < 0.0001). In contrast, β‐EP correlated positively with AHI ( p < 0.0001) but not with BMI ( p = 0.0931). ROC curve analysis identified β‐EP (cutoff: 9.405 ng/L) as a moderate predictor of OSAS (AUC = 0.7986, p < 0.01; sensitivity: 72.22%, specificity: 83.33%). Strikingly, NPY (cutoff: 19.29 ng/L) exhibited perfect discriminative capacity (AUC = 1, p < 0.0001; sensitivity: 97.22%, specificity: 100%). Conclusions: Plasma β‐EP and NPY levels are associated with OSAS severity and may serve as potential biomarkers. However, further validation in larger cohorts is needed to confirm their clinical utility.