Untreated sleep apnea raises risk of Parkinson’s, research finds

People with untreated sleep apnoea face nearly double the risk of Parkinson’s; using CPAP therapy appears to cut that risk, the study of 11m veterans suggests.

The study of more than 11 million US military veterans found that using continuous positive airway pressure (CPAP) therapy significantly reduced this heightened risk.

Obstructive sleep apnoea (OSA) is a common condition where breathing repeatedly stops and starts during sleep, preventing the body from getting adequate oxygen. CPAP devices keep airways open overnight.

Researchers from Oregon Health & Science University and the Portland VA Health Care System analysed electronic health records from veterans who received care through the Department of Veterans Affairs between 1999 and 2022.

The findings revealed a strong link between untreated sleep apnoea and Parkinson’s disease, even after adjusting for factors like obesity, age and high blood pressure. Among millions with sleep apnoea, those who didn’t use CPAP were nearly twice as likely to develop Parkinson’s as those who did.

Parkinson’s is a neurodegenerative condition affecting an estimated one million people in the US, with risk increasing incrementally each year for people over 60. The disease damages brain cells over time, leading to movement difficulties, tremors and cognitive changes.

“It’s not at all a guarantee that you’re going to get Parkinson’s, but it significantly increases the chances.” said co-author Gregory Scott, assistant professor of pathology at OHSU School of Medicine and a pathologist at the VA Portland.

The research suggests that repeated oxygen deprivation during sleep may damage nerve cells over time, which could help explain the link to neurodegeneration.

“If you stop breathing and oxygen is not at a normal level, your neurons are probably not functioning at a normal level either.” said lead author Lee Neilson, assistant professor of neurology at OHSU and staff neurologist at the Portland VA.

“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.”

The findings have immediate implications for clinical practice. Neilson said he intends to prioritise the health benefits of sound sleep with his patients, given the elevated risk identified.

“I think it will change my practice.” he said.

Despite some people with sleep apnoea resisting CPAP due to discomfort or inconvenience, Scott pointed to the experience of many veterans who have embraced the therapy.

“The veterans who use their CPAP love it. They’re telling other people about it. They feel better, they’re less tired. Perhaps if others know about this reduction in risk of Parkinson’s disease, it will further convince people with sleep apnoea to give CPAP a try.”

The study is among the largest to examine sleep disorders and neurodegenerative disease. Previous work has suggested links between sleep quality and brain health, but this study reports a strong association between untreated sleep apnoea and Parkinson’s risk.

The research team included Isabella Montano, Jasmin May, Jonathan Elliott and Miranda Lim from OHSU and the Portland VA Health Care System, along with Yeilim Cho and Jeffrey Iliff from the University of Washington and the VA Puget Sound Health Care System.

Funding came from multiple sources including the VA, the John and Tami Marick Family Foundation, the Collins Medical Trust, the National Institute on Aging of the National Institutes of Health, and the US Army Medical Research Acquisition Activity.

The findings underscore the importance of identifying and treating sleep apnoea, particularly in older adults who may already face elevated risk for neurodegenerative conditions. With CPAP therapy widely available, the research suggests that treating sleep apnoea could represent an important opportunity for Parkinson’s prevention.