American scientists – after a review of millions of health records – have suggested that early treatment of obstructive sleep apnoea might decrease the risk of Parkinson’s disease, reports ABC News.
For the study, published in JAMA Neurology, the team, led by Oregon Health & Science University (OHSU) and the Veterans Affairs Portland Health Care System, looked at the health records of more than 11m veterans from the US Department of Veteran’s Affairs between January 1999 and December 2022 with an average of five years of follow-up.
Although the relative risk was small, researchers found that veterans who received an obstructive sleep apnoea (OSA) diagnosis within a two-year window were almost two times as likely to be diagnosed with Parkinson’s up to six years later than those without sleep apnoea.
However, those who started using CPAP machine within a two-year window of OSA diagnosis reduced their risk of a Parkinson’s diagnosis by about 30%.
A CPAP, or continuous positive airway pressure, machine keeps the airways open so people can receive oxygen while they’re sleeping to improve sleep quality and reduce the risk of health issues.
The risk remained even after the team controlled for other factors that may increase the risk of sleep apnoea or Parkinson’s, including high body mass index, diabetes, high blood pressure, depression, anxiety and traumatic brain injuries.
“We know that people with Parkinson’s have a lot of difficulties with sleep, and so it made sense that maybe sleep problems were happening even earlier, before the disease started,” said Dr Lee Neilson, study co-author and a neurologist at the Portland VA Medical Centre as well an Assistant Professor at OHSU.
“It also made sense that if you are not only not getting good sleep, but if your brain is not getting the right amount of oxygen night in and night out, that could be one hit along the pathway to developing Parkinson’s,” he added.
“So we weren’t necessarily surprised by that, but we were pleasantly surprised that treating with a CPAP machine did make a difference.”
Parkinson’s is a neurodegenerative disorder characterised by the weakening of nerve cells, which become damaged and die.
The most significant loss of neurons occurs in an area near the base of the brain – the substantia nigra. The neurons in the substantia nigra produce dopamine, the neurotransmitter that plays a vital role in controlling movement.
Neilson said the findings show the importance of getting screened for sleep apnoea, with many previous studies showing that the condition can be detrimental to health.
“Just because you have sleep apnoea does not doom you to getting Parkinson’s in the future, but there is a real increased risk,” he said.
Neilson observed that there were two big limitations of the study, one being the over-representation of white, male individuals. Examining under-represented minorities would be important to confirm the findings, he said.
The second limitation is an inability for the team to assess patients’ CPAP adherence or understand why someone would decide to wear or not to wear their CPAP.
He also noted there are many studies showing CPAP adherence was usually good for the first few months of use and then tailed off after the first year.
Dr Richard Isaacson, a Preventative Neurologist at the Institute for Neurodegenerative Disease in Florida, who was not involved in the study, said he was encouraged by the findings.
“I’m not certain that sleep apnoea causes Parkinson’s disease, but it may speed up progression of the disease because, for example, (by) the effect of the amount of oxygen reaching the brain or vascular brain health,” he told ABC News.
He said further studies are needed to better understand whether sleep apnoea itself, or co-factors like being overweight, was a potential risk for Parkinson’s.
Dr Stuart Isaacson, director of the Parkinson’s Disease and Movement Disorders Centre in Boca Raton, Florida, who was also not involved in the study, said the only known causes of Parkinson’s are genetic, and that he would resist from drawing firm conclusions because the study design cannot show true cause.
However, he said he believes the study is important “because it appears to identify that in patients who don’t have Parkinson’s, there may be an increased risk of obstructive sleep apnoea and in treating this, they suggest they be able to modify the risk of developing Parkinson’s”.
Study details
Obstructive Sleep Apnoea, Positive Airway Pressure, and Implications of Early Treatment in Parkinson Disease
Lee Neilson, Isabella Montaño, Jasmine May, et al.
Published in JAMA Neurology on 24 November 2025
Abstract
Importance
Obstructive sleep apnoea (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 semi-structured 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.
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