The Relationship Between Hepcidin and the Severity of Obstructive Sleep Apnea Syndrome and Obesity

The effects of chronic intermittent hypoxia associated with obstructive sleep apnea (OSA) on iron metabolism remain incompletely understood. This study aimed to evaluate whether serum hepcidin levels are associated with OSA severity independently of obesity and systemic inflammation. A total of 136 patients who underwent polysomnography for suspected OSA between April and December 2025 were included in the study. Participants were classified into control and OSA groups according to the Apnea–Hypopnea Index (AHI), and the OSA group was further categorized as mild, moderate, or severe. Demographic and anthropometric characteristics and Epworth Sleepiness Scale scores were recorded. Serum hepcidin levels were measured using an ELISA method and compared between groups, and their associations with clinical and polysomnographic parameters were analyzed. Serum hepcidin levels were significantly higher in patients with OSA than in the control group (48.83 ± 11.92 vs. 41.53 ± 12.43 ng/mL; p < 0.001) and increased progressively with disease severity. Hepcidin levels were not significantly correlated with conventional iron parameters but showed a strong positive association with the Oxygen Desaturation Index (ODI). In multivariable regression analysis, the positive relationship between AHI and serum hepcidin levels remained significant after adjustment for body mass index and C-reactive protein levels (p < 0.001). These findings suggest that elevated serum hepcidin levels in OSA are linked to hypoxic stress independently of obesity and systemic inflammation, indicating that hepcidin may represent a potential biomarker reflecting disease severity in OSA.