Obstructive sleep apnea (OSA) has been linked to a significantly increased risk for Parkinson’s disease (PD). However, early treatment of OSA with continuous positive airway pressure (CPAP) significantly lowered the risk for PD.

“If you stop breathing and oxygen is not at a normal level, your neurons are probably not functioning at a normal level either. Add that up night after night, year after year, and it may explain why fixing the problem by using CPAP may build in some resilience against neurodegenerative conditions, including Parkinson’s,” lead author Lee Neilson, MD, neurologist and assistant professor of neurology at Oregon Health & Science University in Portland, Oregon, said in a news release.

The findings were initially presented at the American Academy of Neurology (AAN) 2025 Annual Meeting and were published online on November 24 in JAMA Neurology.

A Modifiable Risk Factor

While previous studies have suggested a link between the OSA and PD, Neilson and colleagues are the first to investigate whether CPAP can modify the risk for PD incidence.

Using data from the US Department of Veterans Affairs Corporate Data Warehouse, the investigators analyzed data from 11,310,411 veterans (9.8% female; mean age, 60.5 years). Those with incomplete records and those younger than 40 were excluded from the analysis.

OSA and PD were identified based on International Classification of Diseases-10th Revision (ICD-10) codes. In addition, PD was defined by a minimum of 5 years of medical records before the first ICD code and two filled PD medication prescriptions.

Veteran’s use of CPAP was pulled from medical interview data. Age, sex, race, ethnicity, and smoking history were balanced between OSA and non-OSA groups using inverse probability of treatment weighting.

Fewer Falls, Fractures, and Deaths

After accounting for age, sex, race, ethnicity, smoking status, and competing risk for death, the researchers found that OSA was associated with nearly a twofold increased risk for PD (hazard ratio [HR], 1.92, P < .001) compared to no OSA. 

At 6 years of follow-up, OSA was associated with 1.61 additional PD cases per 1000 individuals (95% CI, 1.13-2.09). The association was stronger in women than in men.

Both mild and severe OSA were associated with a higher risk for incident PD (mild: HR, 3.17; 95% CI, 2.45-4.11; severe: HR, 3.42; 95% CI, 2.87-4.09; P < .001).

However, this elevated risk was modifiable: CPAP use within 2 years of OSA diagnosis was linked to a 31% lower risk for PD (HR, 0.69; 95% CI, 0.56-0.85) compared with no CPAP.

The association held after adjustment for BMI, vascular comorbidities, rapid eye movement sleep behavior disorder, hypersomnia, psychiatric conditions, hypertension, traumatic brain injury, and relevant medication exposures.

Early CPAP use was also associated with reduced rates of falls, fractures, and death.

A key limitation of the study was the reliance on electronic health records, which prevented investigators from assessing CPAP adherence beyond the identification of relevant administrative codes.

These data not only suggest that OSA is a modifiable risk factor for PD, they also “establish additional clinical rationale for early screening and intervention of sleep-disordered breathing as a key strategy in supporting brain health,” the investigators noted.

See study for the full list of funding and disclosures.