SAN DIEGO — A small but intriguing study has found that treating obstructive sleep apnea in patients with polycystic ovary syndrome lowered their cortisol levels not only at night, but during the daytime as well.
Obstructive sleep apnea symptoms also greatly improved in five nondiabetic PCOS patients who received continuous positive airway pressure (CPAP) for 8 weeks as part of a study presented at the annual meeting of the Endocrine Society.
Previous research has determined that the risk of obstructive sleep apnea is 30-fold to 40-fold higher in women with PCOS compared with weight-matched controls. It has been theorized that there may be a link between obstructive sleep apnea and the metabolic and hormonal abnormalities associated with the disease.
“These findings strongly suggest that obstructive sleep apnea is likely to contribute to elevated cortisol levels in women with PCOS and could play a role in the risk for adverse metabolic alterations in this patient population,” concluded researchers Eve Van Cauter, Ph.D., and Dr. Esra Tasali, of the department of medicine at the University of Chicago, who presented a poster at the meeting.
Subjects in the study were in their early to mid-30s and had a mean body mass index (kg/m2) of 51. Three of the five had impaired glucose tolerance. CPAP treatments were administered for 8 weeks at the patients' homes, with compliance confirmed by built-in monitors.
Following therapy, mean 24-hour cortisol levels fell from 10.2 mcg/dL to 7.7 mcg/dL. Daytime cortisol levels fell from 10.3 mcg/dL to 7.9 mcg/dL, whereas nighttime cortisol dropped from 10.1 mcg/dL to 7.5 mcg/dL. These decreases were all statistically significant.
The cortisol nadir declined by 40%.
“Interestingly, this decrease in the nadir was associated with the severity of patients' sleep apnea,” Dr. Tasali, a pulmonologist and sleep researcher at the university, said in an interview at the meeting.
CPAP may emerge as a treatment modality in some patients, not only to alleviate symptoms of obstructive sleep apnea, but also to independently target hormonally and metabolically driven symptoms, said Dr. Van Cauter, a professor of medicine at the university.