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

Background-Obstructive sleep apnea syndrome (OSAS) is a common disorder in obese subjects, Visceral fat accumulation (VFA) is a better predictor of co ronary heart disease than body mass index. Leptin is a hormone involved in the control of body weight and fat distribution. The effect of nasal contin uous positive airway pressure (NCPAP) treatment on VFA and serum leptin lev els in OSAS patients has not been known. Methods and Results-VFA and subcutaneous fat accumulation (SFA) were assess ed by CT before and after NCPAP treatment in 22 OSAS patients (mean apnea a nd hypopnea index >50 episodes/h), Serum leptin levels of another 21 OSAS p atients 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 de creased 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). V FA 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 ch anged significantly in the body weight reduction group only (P<0.01). Lepti n levels decreased significantly following 3 to 4 days of NCPAP (P<0.01), w hereas body weight, fasting insulin, and cortisol levels did not change sig nificantly. Conclusions-Correction of sleep disordered breathing by NCPAP may be used t o reduce VFA in OSAS patients. OSAS may have significant effects on the ser um leptin levels.