Project Summary Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder that affects up to 38% of North Americans. OSA causes hypoxemia and oxidative stress that lead to increased risks of cardiovascular diseases, type 2 diabetes and various chronic conditions. It also contributes to health disparities as racial and ethnic minority groups are more likely to experience delay in diagnosis and treatment than non-Hispanic Whites, along with the fact that these minorities may have a higher prevalence of OSA. Treatments of OSA, including continuous positive airway pressure (CPAP) and upper airway surgery, are effective in relieving patients' hypopneic symptoms and therefore also thought to reduce the risks of these morbidities. However, previous studies on CPAP did not show significant impact on these outcomes and findings remain inconclusive due to poor compliance of the participants. In addition, literature regarding the long-term benefits of upper airway surgery is extremely lacking. It is also important to characterize OSA patients who will have higher risks of long-term morbidities. The proposed project will leverage the big data from the National Institutes of Health All of Us Research Program to study the long-term effects of CPAP and surgery on downstream morbidities, and to identify critical predictors for OSA patients who are at risk of these outcomes. In addition, the project aims to evaluate the racial and ethnical disparities in access to OSA treatment, and the mediation effect of socioeconomic and healthcare factors. The project, if successfully carried out, should have important scientific and social implications by providing a better understanding of the benefit of each treatment, facilitating personalized medicine, and reducing health disparities in OSA.