Early diurnal variation of serum leptin and adiponectin in nontreated obstructive sleep apnea disease: a prospective observational study.

BACKGROUND: Obstructive sleep apnea (OSA) is a common disorder resulting in a myriad of adverse vascular risks, including altered inflammatory/anti-inflammatory adipokine balance. Recent studies are yet to agree on how this balance responds to the OSA severity. As it is customary in these studies to obtain a single blood sample in participants after completion of the nocturnal polysomnogram (PSG), we hypothesized that these adipokines' early ultradian pulsatility might contribute to the reported contradictory results.

METHODS: Fasting serum leptin and adiponectin were measured every 15 minutes for one hour in the morning after the diagnostic PSG for 13 adults recruited consecutively from the Salem VAMC Sleep Clinic between September 2006 and October 2007.

RESULTS: No differences in the timed paired samples of leptin (P = 0.30) and adiponectin (P = 0.28) were found in OSA participants (mean apnea-hypopnea index 21.1).

CONCLUSION: Customary protocol of obtaining a single blood sample for leptin and adiponectin after nocturnal PSG seems appropriate.