Serum cytokines as potential biomarkers for diagnosis and monitoring of sleep disorders: A cross-sectional and longitudinal study

Background: Sleep disorders, particularly Obstructive Sleep Apnea (OSA) and Insomnia Disorder (ID), are associated with systemic inflammation. However, the diagnostic and monitoring utility of specific cytokine profiles remains unclear. To identify distinct serum cytokine signatures in OSA and ID compared to healthy controls (HC) at baseline and to evaluate longitudinal changes in these biomarkers following standard treatment. Methods: In this pilot study, 75 cases (25 OSA, 25 ID, 25 HC) were enrolled. Serum levels of IL-6, TNF-a, IL-1b, IL-10, and CRP were measured at baseline using multiplex immunoassay. All patients underwent polysomnography and clinical assessment. The OSA and ID cohorts were re-evaluated after 3 months of treatment (CPAP for OSA, CBT-I for ID) with repeat cytokine analysis. Results: At baseline, the OSA group showed significantly elevated levels of IL-6 (p