A study of more than 11 million U.S. veterans suggests that leaving obstructive sleep apnea untreated is linked to a sharply higher risk of developing Parkinson's disease, while use of CPAP therapy is associated with substantially lower odds of the disorder.
A large-scale study published online on November 24 in JAMA Neurology reports a strong association between untreated obstructive sleep apnea (OSA) and an increased risk of Parkinson's disease among U.S. military veterans.
According to materials from Oregon Health & Science University (OHSU), researchers from OHSU and the Portland VA Health Care System analyzed electronic health records from more than 11 million U.S. veterans who received care through the Department of Veterans Affairs between 1999 and 2022. The cohort study included 11,310,411 veterans, about 13.7% of whom had OSA.
Parkinson's disease, a progressive neurological disorder, affects an estimated 1 million people in the United States, and the risk of developing it rises steadily after age 60, OHSU and associated news reports note.
The new research found that veterans with sleep apnea who did not use continuous positive airway pressure (CPAP) treatment were nearly twice as likely to be diagnosed with Parkinson's disease as those whose apnea was treated with CPAP. This elevated risk remained even after adjusting for potential confounding factors such as obesity, age and high blood pressure, as well as other vascular and psychiatric conditions.
"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, M.D., Ph.D., an assistant professor of pathology in the OHSU School of Medicine and a pathologist at the VA Portland Health Care System, in statements released by OHSU and summarized by multiple outlets.
OSA is a common sleep disorder in which a person's breathing repeatedly stops and restarts during sleep, which can prevent the body from getting enough oxygen. "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, M.D., an 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 authors and institutional statements emphasize that the findings point to an association rather than proof that untreated OSA directly causes Parkinson's disease. Even so, Neilson said the elevated risk outlined in the study reinforces the importance of prioritizing sleep health in clinical care. "I think it will change my practice," he said.
Scott noted that some patients with sleep apnea hesitate to use CPAP, but he highlighted the experiences of many veterans who report clear day-to-day benefits from the treatment. "The veterans who use their CPAP love it," he said. "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 apnea to give CPAP a try."
Experts say further research will be needed to understand the biological mechanisms linking disrupted sleep, low oxygen levels and neurodegeneration, as well as to determine how early and consistent CPAP use might influence long-term Parkinson's risk.