Absence of alterations in serum sex hormone levels in idiopathic REM sleep behavior disorder

Study objectives: More than 85% of the patients presenting to sleep centers with idiopathic REM sleep behavior disorder (RBD) are men. It has been hypothesized that sex hormone abnormalities may be related to this male predominance. The aim of our study was to determine the serum sex hormone levels in consecutive idiopathic RBD male patients who presented to our sleep center. Setting: University hospital sleep disorders center. Participants: Fourteen male idiopathic RBD patients and 16 healthy matched controls. Interventions: NA. Measurements and Results: Serum levels of total testosterone, calculated free testosterone, calculated bioavailable testosterone, luteinizing hormone, follicle stimulating hormone, estradiol-17 beta, sex-hormone binding globulin, and prolactin were not different between idiopathic RBD patients and controls. Conclusion: Serum sex hormone levels are normal in idiopathic RBD, indicating that androgenic abnormalities may not account for its male predominance and pathophysiology.