Endocrine Abstracts

Background and aims: Orexins are hypothalamic neuropeptides involved in energy homeostasis and sleep regulation. We aimed to find the relation between serum orexin-A levels, glucose, and insulin levels, depression and sleep problems in patients with metabolic syndrome.

Materials and methods: This descriptive, cross-sectional study included 43 patients with metabolic syndrome (patient) and 16 healthy subjects (control, age, and sex matched) who applied to endocrinology outpatient clinic. All participants were assessed with sociodemographic questionnaires, anthropometric measurements (body weight, height, waist, and neck circumference), metabolic parameters, the Pittsburgh Sleep Quality Index (PQ9I), Epworth Sleepiness Scale, and Beck Depression Index.

Results: The mean ages were 40.8±10.1 (23–60 years) and 34.6±9.2 (20–48 years), in patient and control group respectively. There was a significant positive correlation between fasting orexin-A and insulin levels and HOMA-IR (r=0.371, P=0.005 and r=0.390, P=0.003 respectively).

The mean serum fasting orexin-A levels were not significantly different (2.06±1.51, 1.21±1.24, P=0.054) between two groups. However postprandial orexin-A levels were significantly higher in patients with metabolic syndrome (1.83±1.58, 0.78±0.91, P=0.007 respectively) compared to healthy subjects. And fasting Orexin-A levels in females were significantly higher than in male subjects (P=0.017).

Global sleep quality was poor (PQ9I>5) in 42.9%, daytime sleepiness scores were high in 58.1% and depression scores were high (>17 points) in 12.8% in the whole group. Global sleep scores were positively correlated with fasting orexin-A levels and waist circumference (r=0.270, P=0.043 and r=0.319, P=0.037 respectively). Fasting and postprandial orexin-A levels in subjects who had poor sleep quality were significantly higher compared to subjects with good sleep quality (P=0.002 and P=0.021 respectively).

Discussion: Higher postprandial orexin A-levels were associated with metabolic syndrome and poor sleep quality. Our findings suggest that orexin A may interact with systems that regulate sleep quality and insulin resistance syndromes and maybe an important therapeutic target for related disorders.