Obstructive Sleep Apnea, Positive Airway Pressure, and Implications of Early Treatment in Parkinson Disease

Importance Obstructive sleep apnea (OSA) is associated with many health conditions, including dementia and early mortality. Prior epidemiological studies linking OSA with Parkinson disease (PD) are conflicting, and no studies have examined the influence of continuous positive airway pressure (CPAP), the criterion standard treatment for OSA, on PD risk. Objective To examine the association between OSA with incident Parkinson disease among US veterans and risk modification by CPAP. Design, Setting, and Participants This electronic health record (EHR)–based cohort study was conducted among US veterans from January 1, 1999, to December 30, 2022, with mean (SD) follow-up of 4.9 (1.8) years. Veterans with PD at the time of exposure or incomplete records were excluded. Data analysis was completed from September 2024 to September 2025. Exposure OSA was defined by its appropriate administrative code; CPAP usage was extracted from a semistructured medical interview field in the EHR. Main Outcomes and Measures The primary outcome, cumulative incidence of PD, was calculated adjusting for competing risk of death after balancing for age, race, sex, and smoking status. Results A total of 13 737 081 US veterans were screened, and 11 310 411 veterans (1 109 543 female veterans [9.8%]) with mean (SD) age of 60.5 (14.7) years were included in analyses. Of included veterans, 1 552 505 (13.7%) had OSA. Veterans with OSA demonstrated 1.61 additional cases of PD (point estimate; 95% CI, 1.13-2.09) at 6 years from diagnosis per 1000 people compared to those without OSA. Results were confirmed when adjusting for body mass index, vascular comorbidities, psychiatric conditions, and relevant medications and were of greater magnitude in female veterans. Case numbers were significantly reduced when treated with CPAP early in the disease course. Conclusions and Relevance In this EHR-based cohort study, OSA appeared to be an independent risk factor for the later development of PD and could be modified by early treatment with CPAP. Effective screening measures and protocols for consistent adherence to CPAP may have large impacts on brain health.