Introduction:
Elevated cardiotrophin-1 (CT-1) and leptin levels are important risk factors for cardiovascular diseases (CVDs). Obstructive sleep apnea syndrome (OSAS) has also been reported to increase this risk. The aim of this study is to evaluate serum concentrations of CT-1 and leptin in patients with OSAS and whether there is a possible association between CT-1, leptin and OSAS severity.

Material and methods:
Fifty newly diagnosed OSAS patients and thirty nonapneic snoring subjects participated in this study. Fasting serum lipid profile markers were evaluated. The measurements of serum CT-1 and leptin levels were carried out using human ELISA kits.

Results:
Significant differences were found in the serum CT-1 and leptin levels between the two groups. Serum median CT-1 levels in patient and control groups, respectively, were 19.47; 8.23 pg/ml and leptin levels were 2.07; 1.29 ng/ml (p < 0.001). In the severe patient group, serum median CT-1 level was statistically significantly higher than the median level in the mild/moderate group. There was no correlation between patients’ leptin and lipid profile parameters and CT-1 concentrations were not associated with triglyceride, cholesterol or LDL cholesterol levels except HDL cholesterol: CT-1 levels were positively correlated with HDL levels (p = 0.02).

Conclusions:
Both CT-1 and leptin were significantly elevated in the patient group. Furthermore, CT-1 and leptin were associated with OSAS and CT-1 was associated with the disease severity.