- A new study finds that having obstructive sleep apnea increases the risk that a person will eventually develop Parkinson’s disease, and the more severe the apnea, the higher the risk.
- CPAP therapy cuts the increased risk of Parkinson’s almost in half, the researchers found.
- Many people who have obstructive sleep apnea do not know that they have the condition, but may experience its symptoms: poor sleep quality, trouble falling asleep, and daytime sleepiness.
People with untreated obstructive sleep apnea (OSA) are more likely to develop Parkinson’s disease than people without OSA, according to a new study. The good news is that the increased risk of Parkinson’s can be significantly reduced with CPAP treatment.
The risk of developing Parkinson’s disease is double for people with OSA who do not receive CPAP treatment.
The research was conducted by Oregon Health and Science University and the Portland Veterans Administration (VA) Health Care System.
The study drew its conclusions through an analysis of health records for 13,737,081 U.S. veterans collected by the Department of Veterans Affairs from 1999 to 2022. The mean age of the study population was 60.5 years, and 9.8% of them were women.
Of the entire study group, 1,552,505 had OSA. Six years from their original OSA diagnosis, there were 1.6 cases of Parkinson’s for every 1,000 individuals with OSA, compared to those without OSA.
The study neither predicts that a person with untreated OSA will certainly develop Parkinson’s, nor does it claim that treatment with a CPAP machine will definitively prevent the condition. Rather, the study describes an increase or decrease, respectively, in the risk of developing Parkinson’s.
This study contributes to the existing research on the relationship between poor sleep and Parkinson’s disease.
“Other studies had looked at a potential link between sleep apnea and Parkinson’s disease, but the results were very mixed, and the methodologies were not as rigorous as what we employed in our study,” said Lee Neilson, MD, the study’s lead author and assistant professor of neurology at Oregon Health & Science University, and staff neurologist in Oregon, VA.
“We were the first to examine not just sleep apnea as a yes/no phenomenon, but also looked at severity. It turns out that those with more severe sleep apnea had an even higher risk of Parkinson’s than those with mild sleep apnea.”
— Lee Neilson, MD
Neilson also said that their study was “the first to examine if prescribing CPAP could modify the risk of Parkinson’s in any way.”
“We were pleasantly surprised to see that getting CPAP within the first two years of a sleep apnea diagnosis reduced the risk of Parkinson’s disease by about 30%,” Neilson told Medical News Today.
“This was particularly compelling,” he continued, “because current clinical practice does not mandate treatment with CPAP at the mild stages. It is largely reserved for those who are clearly symptomatic, like suffering from excessive daytime sleepiness.”
Neilson said this could represent an under-treated population that could benefit from CPAP treatment.
Neilson described what happens to the body when a person experiences an obstructive sleep apnea event:
“Obstructive sleep apnea is a condition whereby the upper airway completely or partially collapses during sleep, which in turn could drop one’s oxygen saturation and trigger an arousal.”
Daniel Truong, MD, is editor in chief of the Journal of Clinical Parkinsonism and Related Disorders, and is a neurologist and medical director of the Truong Neuroscience Institute at MemorialCare Orange Coast Medical Center in Fountain Valley, CA.
He attributed the phenomenon to “the loss of neuromuscular tone during sleep, especially REM.” He said this “allows the soft tissues to occlude the airway despite continued respiratory effort.”
According to Neilson, “While the causes [of OSA] are somewhat more complex, it is simple to think the prototypical person with sleep apnea would be older, and thereby have reduced muscle tone, and overweight, or [have] anatomical differences which can predispose to this airway collapse.”
During an apnea event, said Truong, “the increasingly negative intrathoracic pressure increases venous return and cardiac preload, which stresses the heart and can provoke arrhythmias. The patient develops intermittent hypoxemia.”
After partially awakening to gasp for air, a person’s airway collapses again and again, leading to disrupted sleep for as long as the episode lasts.
People with OSA “have difficulty falling asleep, staying sleep, and being too sleepy during the day,” said Neilson.
Truong described cardiovascular, metabolic, and neurological consequences of OSA, including cognitive impairment, increased risk of stroke, a worsening of movement disorders, and “other effects such as GERD (due to pressure swings), nocturia, depression, and mood disturbance.”
“Airflow blockage creates intermittent hypoxia resulting in tiny ischemia-reperfusion episodes all night. Sleep becomes fragmented; autonomic centers are constantly triggered. This is chronic, cumulative ‘micro-trauma’ to vulnerable neurons and vascular structures.”
— Daniel Truong, MD
OSA is also linked to systemic inflammation, endothelial dysfunction and blood–brain barrier stress. In addition, it disrupts the clearing out of metabolites and misfolded proteins in the brain that normally occurs during deep NREM and stable REM sleep, due to the manner in which it fragments sleep.
“OSA is a persistent intermittent ‘insult generator’, [producing] hypoxia, BP spikes, arousals, and metabolic disruption, repeated thousands of times per month,” Truong said.
Truong said that this study goes to show that “more rigorous screening for OSA in primary care is warranted, and the new [f]indings strengthen that argument.”
“CPAP is safe, effective, and now potentially neuroprotective. Unlike many [Parkinson’s] risk modifiers, OSA has a well-established treatment: non-pharmacologic, relatively low risk, benefits cardiovascular and cognitive health, and now potentially reduces Parkinson’s risk. Few modifiable risk factors offer this spectrum of benefit,” he said.
“25 to 35% of middle-aged adults have OSA. Up to 80–90% remain undiagnosed, especially women and patients [who do not have obesity].”
— Daniel Truong, MD