Sleep apnea may increase risk of developing Alzheimer's disease

November 10, 2017, American Thoracic Society
Sleep Apnea may increase risk of developing Alzheimer's disease
Sleep apnea may increase AD risk . Credit: ATS

Obstructive sleep apnea (OSA) may put elderly people at greater risk of developing Alzheimer's disease (AD), according to new research published online in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

In "Obstructive Sleep Apnea Severity Affects Amyloid Burden in Cognitively Normal Elderly: A Longitudinal Study," researchers report that biomarkers for , the plaque-building peptides associated with Alzheimer's disease, increase over time in with OSA in proportion to OSA severity. Thus, individuals with more apneas per hour had greater accumulation of brain amyloid over time.

According to the authors, AD is a neurodegenerative disorder that afflicts approximately five million older Americans. OSA is even more common, afflicting from 30 to 80 percent of the elderly, depending on how OSA is defined.

"Several studies have suggested that sleep disturbances might contribute to amyloid deposits and accelerate cognitive decline in those at risk for AD," said Ricardo S. Osorio, MD, senior study author and assistant professor of psychiatry at New York University School of Medicine.

"However, so far it has been challenging to verify causality for these associations because OSA and AD share risk factors and commonly coexist."

He added that the purpose of this study was to investigate the associations between OSA severity and changes in AD biomarkers longitudinally, specifically whether amyloid deposits increase over time in healthy elderly participants with OSA.

The study included 208 participants, age 55 to 90, with normal cognition as measured by standardized tests and clinical evaluations. None of the participants was referred by a sleep center, used continuous positive airway pressure (CPAP) to treat sleep apnea, was depressed, or had a medical condition that might affect their brain function. The researchers performed lumbar punctures (LPs) to obtain participants' cerebrospinal fluid (CSF) soluble Aβ levels, and then used positron emission tomography, or PET, to measure Aβ deposits directly in the brain in a subset of participants.

The study found that more than half the participants had OSA, including 36.5 percent with mild OSA and 16.8 percent with moderate to severe OSA. From the total study sample, 104 participated in a two-year longitudinal study that found a correlation between OSA severity and a decrease in CSF A?42 levels over time. The authors said this finding is compatible with an increase in amyloid deposits in the brain; the finding was confirmed in the subset of participants who underwent amyloid PET, which showed an increase in amyloid burden in those with OSA.

Surprisingly, the study did not find that OSA severity predicted cognitive deterioration in these healthy elderly adults. Andrew Varga, MD, PhD, study coauthor and a physician specializing in sleep medicine and neurology at the Icahn School of Medicine at Mount Sinai in New York, said this finding suggests that these changes were occurring in the preclinical stages of AD.

"The relationship between amyloid burden and cognition is probably nonlinear and dependent on additional factors," he added. This study finding may also be attributable to the study's relatively short duration, highly educated participants and use of tests that fail to discern changes in cognitive abilities that are subtle or sleep-dependent, the authors wrote.

The high prevalence of OSA the study found in these cognitively normal elderly participants and the link between OSA and burden in these very early stages of AD pathology, the researchers believe, suggest the CPAP, dental appliances, positional therapy and other treatments for sleep apnea could delay cognitive impairment and dementia in many older adults.

"Results from this study, and the growing literature suggesting that OSA, cognitive decline and AD are related, may mean that age tips the known consequences of OSA from sleepiness, cardiovascular, and metabolic dysfunction to brain impairment," Dr. Osorio said. "If this is the case, then the potential benefit of developing better screening tools to diagnose OSA in the elderly who are often asymptomatic is enormous."

Explore further: Sleep and Alzheimer's disease connection

Related Stories

Sleep and Alzheimer's disease connection

October 17, 2017
How often do you get a good night's sleep? Centers for Disease Control and Prevention guidelines recommend adults get an average of at least seven hours of sleep a night. Dr. Ronald Petersen, a Mayo Clinic neurologist, says ...

Can poor sleep boost odds for Alzheimer's?

July 18, 2017
(HealthDay)— Breathing problems during sleep may signal an increased risk for Alzheimer's disease, a trio of studies suggests.

Sleep disturbance linked to amyloid in brain areas affected by Alzheimer's disease

December 9, 2014
Healthy, elderly research participants who report being more sleepy and less rested have higher levels of amyloid deposition in regions of the brain that are affected in Alzheimer's disease, according to a report presented ...

AAIC: Alzheimer biomarkers up with sleep disordered breathing

July 18, 2017
(HealthDay)—Biological changes in the brain may underlie a relationship between sleep disordered breathing (SDB) and Alzheimer's disease, according to new research. A trio of studies on the matter were scheduled for presentation ...

Link between sleep and cognitive impairment in the elderly

January 31, 2017
Daytime sleepiness is very common in the elderly with prevalence rates of up to 50 percent. Caused by sleep-disordered breathing (SDB), a disruption of normal breathing during sleep, these cause recurrent awakenings and subsequent ...

Sleep problems may be early sign of Alzheimer's

July 5, 2017
Poor sleep may be a sign that people who are otherwise healthy may be more at risk of developing Alzheimer's disease later in life than people who do not have sleep problems, according to a study published in the July 5, ...

Recommended for you

Rate of dementia on the decline—but beware of growing numbers

April 17, 2018
The good news? The rate of older Americans with dementia is on the decline.

Research offers potential insight into Alzheimer's disease

April 16, 2018
Slightly elevated beta-amyloid levels in the brain are associated with increased activity in certain brain regions, according to a new study from the Center for Vital Longevity (CVL) at The University of Texas at Dallas.

Americans with a college education live longer without dementia and Alzheimer's

April 16, 2018
Education gives people an edge in their later years, helping them to keep dementia at bay and their memories intact, a new USC-led study has found.

Evidence mounts for Alzheimer's, suicide risks among youth in polluted cities

April 13, 2018
A University of Montana researcher and her collaborators have published a new study that reveals increased risks for Alzheimer's and suicide among children and young adults living in polluted megacities.

Improving brain function in Alzheimer's disease mouse model

April 11, 2018
Using two complementary approaches to reduce the deposits of amyloid-beta in the brain rather than either approach alone improved spatial navigation and memory in a mouse model of Alzheimer's disease. These findings suggest ...

Sleepless nights show ties to Alzheimer's risk

April 10, 2018
Even one night of lost sleep may cause the brain to fill with protein chunks that have long been linked to the development of Alzheimer's disease, a new study warns.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.