Decreased levels of serum omentin-1 in patients with obstructive sleep apnoea syndrome

Background: Inflammation is involved in the mechanism of obstructive sleep apnoea syndrome (OSAS). Omentin, a newly discovered adipokine, is implicated to play an anti-inflammatory role. This study aims to determine whether serum levels of omentin-1 are associated with the presence and severity of OSAS. Methods: This study consisted of 192 patients with OSAS and 144 healthy subjects. Serum levels of omentin-1 were measured using enzyme-linked immunosorbent assay. Results: Serum omentin-1 levels were significantly decreased in OSAS patients compared with healthy controls. Multivariable logistic regression analysis revealed that serum omentin-1 levels were inversely associated with the presence of OSAS (odds ratio 0.520, 95% confidence interval 0.433 to 0.623; P < 0.001). Severe OSAS patients had significantly lower serum omentin-1 levels compared with mild and moderate OSAS patients. Spearman correlation analysis showed that serum omentin-1 levels were correlated with the severity of OSAS. Simple linear regression analysis showed that the serum levels of omentin-1 were negatively correlated with waist circumference, body mass index, systolic blood pressure, homeostasis model assessment of insulin resistance (HOMA-IR), C-reactive protein (CRP), and apnoea-hypopnoea index in patients with OSAS. Furthermore, only HOMA-IR and CRP remained inversely associated with serum omentin-1 after multiple stepwise regression analysis. Conclusion: Decreased serum omentin-1 levels could be considered as an independent predictive marker of the presence and severity of OSAS.