Impact of Continuous Positive Airway Pressure Treatment on Leptin Levels in Patients with Obstructive Sleep Apnea Syndrome.

BACKGROUND

There is growing evidence that leptin regulation is altered in obstructive sleep apnea syndrome (OSAS). Several potential mechanisms have been purported to explain how sleep apnea may alter leptin levels. We investigated whether repeated apneas, hypoxia, or excessive daytime sleepiness influenced the levels of leptin in OSAS patients. We also evaluated whether a 3-month continuous positive airway pressure (CPAP) treatment affected leptin levels in patients.

METHODS

Randomly selected 31 untreated, otherwise healthy male, overweight [body mass index (BMI) >25 kg/m(2)] obstructive sleep apnea syndrome (OSAS) patients [apnea-hypopnea index (AHI) ≥15] and 25 control (AHI <5) were included in this study. To confirm the diagnosis, all subjects underwent standard polysomnography. Serum samples were taken at 07:00-08:00 a.m. after overnight fasting. The OSAS patients that had regular CPAP treatment (n=26) were re-evaulated 3 months later.

RESULTS

Leptin levels (50.5±17.5 grams/L in OSAS and 56.3±25.5 grams/L in controls) and lipid profiles (TC, TGs, HDL-C, and LDL-C) between patient and control groups did not differ (P>0.05). Leptin levels were not correlated with the AHI, oxygen saturation, or excessive daytime sleepiness. CPAP treatment did not significantly change the (BMI), waist and neck circumference, or leptin levels in OSAS patients. Furthermore, we found no correlation between the decrease in serum leptin levels and parameters that were improved by CPAP treatment.

CONCLUSION

Leptin levels and lipid profile of overweight subjects with and without OSAS were not different, and our results suggest that OSAS-related parameters and CPAP treatment do not play a significant role in the serum leptin levels.