Relationship between hepcidin levels and periodic limb movement disorder in patients with obstructive sleep apnea syndrome

This study was aimed to assess potential correlations between periodic leg movement (PLM) index, hepcidin levels, and iron status in patients with obstructive sleep apnea syndrome (OSAS). Forty-four newly diagnosed OSAS patients and 49 non-apneic controls were enrolled in this study. All patients underwent polysomnographic evaluation. The hepcidin, iron, ferritin, total iron binding capacity, and C-reactive protein levels were measured. The mean age was 47.4 +/- 7.2 years (18-68) in the OSAS group and 44.9 +/- 11.1 years (23-65) in the control group. There were no differences in age, gender, and smoking between OSAS patients and controls. Mean apnea-hypopnea index (AHI) was 25.1 events/h. Mean serum hepcidin levels were significantly higher in OSAS subjects (725.9 ng/ml) than in control subjects (646.0 ng/ml) (p < 0.001). Serum iron levels were significantly lower in the OSAS and PLM disorder groups than in control subjects (p < 0.001). Serum hepcidin levels were significantly correlated with AHI (r = 0.453) and PLM index (r = 0.114). Serum iron levels were significantly negatively correlated with AHI (r = -0.169) and PLM index (r = -0.180). In our study, the level of hepcidin was increased in patients with OSAS. Our study indicates that levels of hepcidin correlate with the AHI and PLM index severity of OSAS.