Can Treating OSA Reduce Dementia Risk?

The answer may be “yes.” A recent study found that older adults who received positive airway pressure (PAP) therapy prescribed for obstructive sleep apnea (OSA) may be less likely to develop Alzheimer disease and other types of dementia.1 

The study, conducted by researchers from the Michigan Medicine Sleep Disorders Centers (University of Michigan), analyzed Medicare claims of more than 50,000 Medicare beneficiaries aged ≥65 who had been diagnosed with OSA.2 The question at the heart of the study was “were those people who used PAP therapy less likely to receive a new diagnosis of dementia or mild cognitive impairment over the next 3 years, compared with people who did not use PAP?”2

Lead author Galit Levi Dunietz, PhD, MPH, an assistant professor of neurology as well as a sleep epidemiologist said, “We found a significant association between positive airway pressure use and lower risk of Alzheimer’s and other types of dementia over 3 years, suggesting that positive airway pressure may be protective against dementia risk in people with OSA.”

Tiffany J. Braley, MD, MS, study principal investigator and associate professor of neurology noted, “If a causal pathway exists between OSA treatment and dementia risk, as our findings suggest, diagnosis and effective treatment of OSA could play a key role in the cognitive health of older adults.”2

The importance of adherence to PAP therapy

“Adherence to PAP therapy was also associated with lower odds of incident Alzheimer disease diagnosis,”2 the authors concluded. But adherence to therapy is a difficult issue. 

Despite the high efficacy of continuous positive airway pressure (CPAP) to reverse upper airway obstruction in sleep apnea, treatment effectiveness is limited by variable adherence to prescribed therapy. When adherence is defined as greater than 4 hours of nightly use, 46% to 83% of patients with OSA have been reported to be nonadherent to treatment. Evidence suggests that use of CPAP for longer than 6 hours decreases sleepiness, improves daily functioning, and restores memory to normal levels.3

One of the most dramatic immediate effects of any medical treatment is the ability of continuous positive airway pressure (CPAP) treatment to reverse the repetitive upper airway obstruction of sleep apnea and associated daytime sleepiness. Patients will describe the effect as emerging from a daytime fog and being able to live a productive and healthy life. CPAP, the primary treatment for OSA, has been shown to normalize sleep architecture, reduce daytime sleepiness, enhance daily function, elevate mood, reduce automobile accidents, and decrease blood pressure and other cardiovascular events.4

“As with any observational study,” the authors concluded, “causality and its direction cannot be established beyond doubt. While OSA diagnosis preceded the diagnosis of dementia, reverse causality cannot be fully ruled out. As noted, the typical age of OSA onset greatly precedes the typical age of dementia onset, but future studies over longer time intervals may be needed to confirm that the association in the present data between OSA treatment or adherence and lower incidence of dementia does not arise because dementia impedes subsequent OSA treatment and adherence.”2

Positive news for patients

Physicians and clinicians working with patients with sleep apnea are well aware of the negative reactions of many patients to using PAP therapy. However, the overwhelming evidence in favor of this therapy—including this exciting development regarding Alzheimer disease—should work in favor of better acceptance and adherence. 

Screening and testing for sleep apnea

The results of this study also point again to the continued need for increased screening and testing of patients suspected of having sleep apnea which must, of course, happen before the beginning of any treatment.  

Screening is done primarily by using one of 3 questionnaires, after learning of patient concerns regarding daytime sleepiness, and so forth. The questionnaires are the Epworth Sleepiness Scale (ESS), the STOP-BANG Sleep Questionnaire, and the Berlin Questionnaire.5

In addition to overnight, in-laboratory sleep studies using polysomnography, home sleep apnea tests (HSATs) are available that are portable, convenient, and less intrusive.6 HSATs have become popular with patients who, during the pandemic, prefer to stay at home, as well as patients fully embracing all forms of digital healthcare such as remote monitoring.

REFERENCES

1

Otman H. Treating sleep apnea may reduce dementia risk. Med Xpress. Apr 10, 2021. https://medicalxpress.com/news/2021-04-apnea-dementia.html

2.

Dunietz GL, Chervin RD, Burke JF, Conceicao AS, Braley TJ. Obstructive sleep apnea treatment and dementia risk in older adults. Sleep. 2021;44(9):zsab076. doi: 10.1093/sleep/zsab076

3.

Weaver TE, Grunstein RR. Adherence to continuous positive airway pressure therapy: the challenge to effective treatment. Proc Am Thorac Soc. 2008;5(2):173-178. doi: 10.1513/pats.200708-119MG

4.

Gay P, Weaver T, Loube D, Iber C; Positive Airway Pressure Task Force; Standards of Practice Committee; American Academy of Sleep Medicine. Evaluation of positive airway pressure treatment for sleep related breathing disorders in adults. Sleep 2006;29(3):381-401. doi: 10.1093/sleep/29.3.381

5.

Three different ways you can screen for sleep apnea. HomeSleep, LLC, blog. Sept 21, 2018. 

https://www.homesleepllc.com/blog/three-different-ways-you-can-screen-for-sleep-apnea

6.

American Sleep Association. At-home sleep apnea test. https://www.sleepassociation.org/sleep-apnea/testing/at-home/