Influence of treatment on leptin levels in patients with obstructive sleep apnoea.

Obstructive sleep apnoea syndrome (OSAS) is a common disorder in obesity. Leptin, an adipocyte-derived signalling factor, plays an important role in metabolic control. There is growing evidence that leptin regulation is altered in OSAS. Therefore, the aim of this study was to test the hypothesis that effective treatment will influence leptin levels in OSAS patients. Serum leptin levels were determined in 86 consecutive patients (aged 57.5 +/- 11.0 yrs) with polysomnographically verified OSAS. In addition, leptin levels were reassessed and treatment efficacy was evaluated by polysomnography after 6 months of therapy. Patients were treated with continuous or bilevel positive airway pressure, a mandibular advancement device or conservatively, depending on the clinical symptoms. Mean serum leptin levels did not change with treatment in the whole study group (7.3 +/- 5.0 versus 7.5 +/- 4.8 ng.mL-1), however, leptin levels decreased in effectively treated patients (8.5 +/- 5.0 versus 7.4 +/- 5.1 ng.mL-1) while they increased in ineffectively treated patients (5.0 +/- 4.0 versus 7.7 +/- 4.1 ng.mL-1). Furthermore, not only was there a significant and independent correlation between the change in leptin levels with treatment and the change in body mass index, but also with the change in apnoea/hypopnoea index. Effective treatment of sleep-disordered breathing may have significant effects on leptin levels in obstructive sleep apnoea syndrome patients. Changes in leptin levels are related to changes in apnoea/hypopnoea index in obstructive sleep apnoea syndrome patients.