Ghrelin, leptin, adiponectin, and resistin levels in sleep apnea syndrome: role of obesity

The aim of this study was to investigate the relationship among plasma leptin, ghrelin, adiponectin, resistin levels, and obstructive sleep apnea syndrome [OSAS]. Fifty-five consecutive newly diagnosed OSAS patients and 15 age-matched nonapneic controls were enrolled in this study. After sleep study between 8:00 AM and 9:00 AM on the morning, venous blood was obtained in the fasting state to measure ghrelin and adipokines. Serum ghrelin levels of OSAS group were significantly [P<0.05] higher than those of the control group. No significant difference was noted in the levels of leptin, adiponectin, and resistin in OSAS group when compared to controls. There was a significant positive correlation between ghrelin and apnea-hypopnea index [AHI] [r=0.237, P<0.05] or the Epworth sleepiness scale [ESS] [r=0.28, P<0.05]. There was also a significant positive correlation between leptin and body mass index [r=0.592, P<0.0001]. No significant correlation was observed between leptin, adiponectin, resistin, and any polysomnographic parameters. Our findings demonstrated that serum ghrelin levels were higher in OSAS patients than those of control group and correlated with AHI and ESS. Further studies are needed to clarify the complex relation among OSAS, obesity, adipokines, and ghrelin