Identification of Biomarkers of Obstructive Sleep Apnea.

Obstructive sleep apnea (OSA) is a common sleep disorder associated with intermittent hypoxia, systemic inflammation, oxidative stress, and an increased risk of cardiovascular and metabolic diseases. Current diagnostic methods are effective but have limited availability and do not adequately predict disease burden or treatment response. The purpose of this study is to identify and validate blood biomarkers that may improve the screening, diagnosis, risk stratification, and monitoring of adults with OSA. A total of 120 participants will undergo clinical evaluation and overnight polysomnography. Participants with moderate-to-severe OSA will be randomly assigned to either immediate or delayed positive airway pressure (PAP) therapy, while participants without OSA will serve as controls. Blood samples will be collected at predefined time points and analyzed for inflammatory, metabolic, oxidative stress, and other candidate biomarkers. The study aims to determine which biomarkers are associated with OSA severity and how they change in response to PAP therapy. The results may contribute to the development of more accessible and personalized diagnostic and monitoring strategies for patients with OSA.

Inclusion Criteria: 1. Participants with obstructive sleep apnea (OSA): * Age 18 to 65 years. * Moderate or severe obstructive sleep apnea confirmed by overnight polysomnography (apnea-hypopnea index \[AHI\] ≥15 events/hour). * Willing and able to provide written informed consent. * Willing to undergo repeated blood sampling and study assessments. * Willing to use positive airway pressure (PAP) therapy and accept random assignment to immediate or delayed treatment. 2. Control participants: * Age 18 to 65 years. * No obstructive sleep apnea (AHI \