Untreated Sleep Apnea and Its Link to Dementia
Last updated: March 2023
Research has confirmed a link between obstructive sleep apnea (OSA) and increased risk for forms of dementia such as Alzheimer’s disease. OSA and Alzheimer’s are common comorbidities (meaning they occur at the same time) in people who are middle-aged or older.1
How sleep apnea can lead to dementia
The key problem of OSA isn’t limited to the way it disrupts the quality and quantity of deep sleep we get every night. Levels of oxygen in the blood will drop frequently overnight as a result of these breathing pauses known as apneas.
Hypoxia and toxin buildup
This low blood oxygen condition is known as hypoxia. In hypoxia, there isn’t enough available oxygen in the bloodstream to sustain the body’s tissues and functions. Hypoxia, it turns out, creates the perfect conditions for depositing certain toxins known as beta-amyloids, which may collect in the central nervous system. These toxins create what’s known as amyloid burden.2
Amyloid burden is considered a marker for identifying the presence of conditions that will likely (or may already) lead to dementia. Neurologists look at this marker when they think a person may have Alzheimer’s. The doctor will also look at measures of cognitive (thinking) performance like:
- Processing speed of the central nervous system (brain, spine, and part of the eyes)
Is amyloid burden a bad thing?
As we age, we may experience a slight amyloid burden. That’s normal the older we get. But it’s the buildup of amyloid into plaques that’s worrisome. These plaques are indicators that may eventually confirm the development of dementia.
A study confirmed a positive link between amyloid burden and OSA. In other words, the more severe the OSA, the greater the amyloid burden, and the higher the risk for developing – or worsening – forms of dementia such as Alzheimer’s.
What about snoring?
Not all cases of snoring lead to OSA, but in most cases of OSA, snoring is a major symptom (especially if it’s loud and frequent). Should you or someone you know who snores be concerned?
Sleep studies and known risk groups
Research suggests you have a preliminary sleep study if you're already a member of a known risk group. In 1 study, more than 9 out of 10 people who’d already been diagnosed with mild to moderate Alzheimer’s were also found to have OSA.3
Among them, half were dealing with severe OSA. Putting these facts together, it’s likely that those with severe OSA have much higher risks for developing or worsening Alzheimer’s, especially if they don’t treat their OSA.3
OSA requires treatment
Unlike snoring, OSA is considered a chronic condition that requires treatment. It’s highly unlikely that someone with OSA will be “cured” of it, but maintaining good breathing patterns while sleeping is the most common approach. Without treatment, however, many of the characteristic symptoms of Alzheimer’s may worsen, especially those related to cognitive decline.
Genetic science also reveals that certain markers linked to Alzheimer’s share features in common with OSA. These include:4
- Increased inflammation
- Oxidative stress
- Disrupted metabolism
- Amyloid burden
Treat OSA for better overall health
The good news? OSA can be successfully managed by several approaches. Positive airway pressure or PAP therapies, oral devices, neurostimulation implants, and surgical procedures are all options. Researchers are also looking into oral medicines as a way to improve breathing during sleep. Treating OSA, then, serves as a critical preventive measure in situations where dementia or cognitive dysfunction may already be suspected but not yet diagnosed.
Sleep tests in a lab or at home
If you or your loved one experience cognitive symptoms or problems with breathing while asleep, take heart. You may not need to go in for the full in-lab study to determine whether snoring issues are actually a case of hidden OSA. For many, a simple home test may be all it takes to know whether it’s just snoring or something else. While a sleep test won’t diagnose dementia, it’ll at least lead to treatment for any sleep disorders that might lay the groundwork for dementia.
Treating OSA can help delay or prevent Alzheimer’s
In 2018, the American Academy of Sleep Medicine (AASM) issued a health advisory stating:5
- "Significant evidence suggests that insufficient sleep or poor sleep may in fact contribute to the development of Alzheimer’s disease."
- "Obstructive sleep apnea, one common cause of poor sleep, may increase the risk of Alzheimer’s disease."
- "When sleep apnea remains untreated, the ongoing, repetitive sleep disturbance, low oxygen levels, or other adverse effects such as increased beta-amyloid may contribute to the progression of Alzheimer’s disease."
Even if dementia or cognitive decline isn’t suspected, the AASM encourages diagnosis and treatment of suspected OSA specifically to delay or prevent Alzheimer’s from developing as the result of an elevated amyloid burden over the long haul.
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