Update on Untreated Sleep Apnea and Its Link to Dementia
Recently, research confirmed a link between obstructive sleep apnea (OSA) and increased risk for forms of dementia such as Alzheimer’s disease (AD).1
Both OSA and AD are common comorbidities (meaning, they can both occur at the same time) in people middle-aged or older.
What can we do if we find ourselves, or a loved one we may be caring for, in this situation?
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 which 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 (CNS). These toxins create what’s known as amyloid burden.2
Amyloid burden is considered a marker for identifying the presence of conditions that’ll likely (or may already) lead to dementia. It’s this measure — when considered along with cognitive performance measures like memory, reasoning, and CNS processing speed — that neurologists consult when they suspect a patient may have AD.
Is amyloid burden a bad thing?
As we age, we may experience a slight amyloid burden. That’s normal, the older we get. However, it’s the elevated buildup of amyloid into plaques that’s worrisome, as these are indicators that may eventually confirm the development of dementia.
The recent study mentioned beforehand confirms a positive link between amyloid burden and OSA. In other words, the more severe the OSA, the greater the amyloid burden, the higher risk for developing — or worsening — forms of dementia such as AD.
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 a preliminary sleep study may be called for if you're already a member of a known risk group. More than 90 percent of subjects in one study of people who’d already been diagnosed with mild to moderate AD were also found to have OSA.3
Among them, half were dealing with severe OSA. Putting two and two together, it’s likely that those with severe OSA have much higher risks for developing or worsening their AD, especially if they don’t treat their OSA.
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 AD may worsen, especially those related to cognitive decline.
Genetic science also reveals that certain markers linked to AD also share features in common with OSA. These include increased inflammation, oxidative stress, disrupted metabolism, and amyloid burden.4
Treat OSA for better overall health
The good news? OSA can be successfully managed by several approaches. PAP therapies, oral devices, neurostimulation implants, and surgical procedures are all options, with researchers looking into oral medications as another 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 — or both — take heart: you may not need to go in for the full in-lab study to determine whether possible 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 breathing disorders which might lay the groundwork for dementia to take place.
Treating OSA can help delay or prevent AD
In 2018, the American Academy of Sleep Medicine (AASM) issued a health advisory saying that "significant evidence suggests that insufficient sleep or poor sleep may in fact contribute to the development of Alzheimer’s disease…” and that “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 progression of Alzheimer’s disease."5
Even if dementia or cognitive decline isn’t suspected, the AASM encourages diagnosis and treatment of suspected OSA specifically to delay or prevent AD from developing as the result of an elevated amyloid burden over the long haul.
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