Evaluation of the Relationship Between Orexin A, Peptide YY, AgRP, and POMC Levels and Sleep Disorders in Children with Malnutrition

Background: Malnutrition and sleep disturbances are common in childhood and are associated with neuropeptides that regulate appetite and circadian rhythms. Hypothalamic peptides such as orexin A, agouti-related protein (AgRP), proopiomelanocortin (POMC), and peptide YY (PYY) play important roles in energy balance and eating behavior; however, their specific functions in pediatric malnutrition remain unclear. This study aimed to determine the levels of these peptides in malnourished children and to examine their relationship with eating and sleep behaviors. Methods: This case–control, cross-sectional study included 99 children aged 5–15 years diagnosed with malnutrition and 85 age-matched healthy controls. Blood samples were collected from all participants, and peptide levels were measured using ELISA. Additionally, the Children’s Eating Behaviour Questionnaire (CEBQ) and the Children’s Sleep Habits Questionnaire (CSHQ) were administered to assess eating patterns and sleep behaviors. Statistical comparisons and hierarchical logistic regression analyses were performed. Results: Orexin A and PYY levels were significantly higher in malnourished children than in controls (p < 0.001). No significant group differences were found for AgRP and POMC, although AgRP tended to be lower and POMC higher in the malnutrition group. Regression analyses identified orexin A and PYY as significant predictors of malnutrition. Orexin A showed a positive correlation with emotional undereating. Sleep habits did not differ significantly between groups. Conclusions: Elevated orexin A and PYY levels may function as potential neuropeptidergic biomarkers of malnutrition. Their association with emotional eating highlights the psychobiological components of malnutrition. Further longitudinal studies are warranted to clarify causal mechanisms and support clinical translation.