Relationship of Serum Orexin-A Levels with Obesity: A Cross-Sectional Association Study

Objective: the aim of this study is to assess the role of orexin-a hormone and its relationship with obesity in cohort of adults with obesity in work region. material-method: a total of 258 subject, aged 18-60 years, who applied to sleep disorder centers of medicine faculty of süleyman demirel university and isparta state hospital chest disease and sleep laboratory of a city were taken into the study. according to their body mass index (bmi), subjects were grouped into five categories (normal weight, overweight, moderately obese, severely obese and morbidly obese). results: plasma samples from subjects were assayed for each plasma parameter using commercially available analytic systems. plasma orexin-a levels correlated negatively with bmi (r=-0.653, p<0.001) and c-reactive protein (crp) (r=0.391, p<0.001). in moderately obese, severely obese and morbidly obese individuals, orexin-a levels were significantly lower when compared to normal weight and overweight groups (all p<0.0001). bmi correlated positively with low-density lipoprotein cholesterol (ldl-c) (r=0.485, p<0.001) and crp (r=0.140, p<0.01). in moderately obese subjects have significantly highest plasma very low density lipoprotein cholesterol (vldl-c) (p<0.05), triglyceride (tg) (p<0.05) and total cholesterol (p<0.001) levels compared to other bmi groups. conclusions: our results confirmed that orexin-a acts also in a peripheral manner. the fact that lower levels of plasma orexin-a are present in obese individuals implicates that it is involved in the regulation of human energy metabolism, and the activity of orexin-a is disturbed in obesity. obesity is associated with elevated levels of crp. the positive associations of obesity with elevated crp levels suggest the importance of reducing obesity or healty weight loss to prevent elevations in obesity-related systemic inflammation.