Testosterone and estradiol are not affected in male and female patients with obstructive sleep apnea treated with continuous positive airway pressure

Background Continuous positive airway pressure (CPAP) improves symptoms in patients with obstructive sleep apnea syndrome (OSAS). It is currently unclear, whetherCPAPalso alters endocrine parameters such as sex hormone levels. In a previous study, we have found no changes in sex hormones in patients with OSAS after one night with CPAP. Aim The aim of this study was to prove long-term effects of CPAP on sex hormone concentrations in patients with OSAS. Methods Twenty-two women and 67 men with severe OSAS (respiratory distress index > 30/h) were enrolled in the study. Fasting blood venous samples were taken before CPAP therapy and after 1 and 6 months of CPAP treatment. Testosterone and estradiol were measured in all samples using commercially available ELISA kits. Results No effects of long-term CPAP treatment were found on testosterone or estradiol levels in OSAS patients of either gender. Conclusions The results are in line with previous smaller studies. However, our study is larger and longer than previously published studies. In addition, this is the first study analyzing the effects of CPAP on testosterone and estradiol and in both genders. Positive effects of CPAP on sexual functions reported in other studies might, thus, be mediated by other than endocrine effects.