Changes in intra-abdominal visceral fat and serum leptin levels in patients with obstructive sleep apnea syndrome following nasal continuous positive airway pressure therapy

Background-Obstructive sleep apnea syndrome (OSAS) is a common disorder in obese subjects, Visceral fat accumulation (VFA) is a better predictor of coronary heart disease than body mass index. Leptin is a hormone involved in the control of body weight and fat distribution. The effect of nasal continuous positive airway pressure (NCPAP) treatment on VFA and serum leptin levels in OSAS patients has not been known. Methods and Results-VFA and subcutaneous fat accumulation (SFA) were assessed by CT before and after NCPAP treatment in 22 OSAS patients (mean apnea and hypopnea index >50 episodes/h), Serum leptin levels of another 21 OSAS patients were measured before and after 3 to 4 days of NCPAP to gain insight into the mechanism by which NCPAP affects fat distribution. VFA and SFA decreased significantly after 6 months of NCPAP treatment (236+/-16 to 182+/-14cm(2), P=0.0003 and 215+/-21 to 189+/-18 cm(2), P=0.003, respectively). VFA decreased significantly in the body weight reduction group (n=9, P<0.01) and the no body weight reduction group (n=13, P<0.03), In contrast, SFA changed significantly in the body weight reduction group only (P<0.01). Leptin levels decreased significantly following 3 to 4 days of NCPAP (P<0.01), whereas body weight, fasting insulin, and cortisol levels did not change significantly. Conclusions-Correction of sleep disordered breathing by NCPAP may be used to reduce VFA in OSAS patients. OSAS may have significant effects on the serum leptin levels.