Endocrine Abstracts

Introduction: Obstructive sleep apnea syndrome (OSAS) is characterized by chronic inflammation. Hepcidin is an acute-phase protein involved in iron metabolism. Increase in hepcidin has been shown in OSAS. Testosterone probably exerts inhibitory effect on hepcidin levels and even trump iron and inflammation-mediated mechanism in chronic inflammatory state. On the other hand iron balance may influence gonadal axis. The aim of this study was to assess whether hypogonadism in OSAS could be associated with iron metabolism.

Material and Methods: We recruited 92 males. Mean age was 61 years old. Sixty nine were diagnosed with OSAS, based on polysomnography. This group was divided into two subgroups. First comprised of 45 eugonadal men (g1), while the second included 24 hypogonadal patients (g2). Control group consisted of 23 patients with normal testosterone levels and normal sleep pattern (g3). We measured multiple parameters, among them: serum testosterone, LH, CRP, insulin levels and irone balance parameters.

Results: We have found significant differences in testosterone (g1>g2, g3>g2; P<0.0000), iron (g3>g1, g3>g2; P=0.0378), CRP (g2>g3; P=0.0389), BMI (g1>g3, g2>g3; P=0.0065), insulin (g2>g1; g2>g3; P=0.0153) and hemoglobin (g3>g1, g3>g2, P<0.0000) between groups. There was a tendency toward statistically significant difference in hepcidin levels (g1>g2, g1>g3; P=0.0513). On linear regression in a whole group testosterone level was inversely associated with hepcidin (P=0.0152; β= -0,1804), insulin (P=0.0024; β= -0,1409) and BMI (P=0.0042; β= -0,3589). On multiple regression BMI and hepcidin were independent factors negatively influencing testosterone levels (P=0.0009).

Conclusion: Changes in testosterone in males with OSAS might be at least partially attributed to hepcidin concentration. Metabolic factors such as insulin and BMI negatively influence gonadal axis. The exact mechanism of potential mutual relationship between iron homeostasis and gonadal status in men with OSAS remains to be elucidated.