A recent study released by the Mayo Clinic has highlighted a link between a health condition called sleep apnea and the accumulation of a brain biomarker associated with Alzheimer’s disease
Heavy snorers may have higher accumulations of the toxic protein tau — a bio-hallmark of Alzheimer’s disease — in the part of the brain that manages memory, navigation and perception of time.
The new evidence, to be presented May 4-10 at the American Academy of Neurology‘s annual meeting in Philadelphia, supports a major link between an increased risk for dementia and sleep disruption.
That’s especially true for obstructive sleep apnea, researchers say, which is a potentially serious disorder in which breathing repeatedly stops during sleep, researchers say. Using the population-based Mayo Clinic Study of Aging, researchers identified 288 people 65 and older who did not have dementia.
“Our research results raise the possibility that sleep apnea affects tau accumulation,” says lead study author Dr. Diego Z. Carvalho, a neurology fellow at Mayo, in a statement.
Participants were asked to track when their snoring bed partners stopped breathing during sleep — then brain scans looked for a buildup of the toxic protein in the entorhinal cortex, the brain zone deep behind the nose that’s most susceptible to tau accumulation.
The entorhinal cortex stores and retrieves info related to visual perception when experiences happen, Carvalho writes, while the dysfunctional tau protein forms “tangles in the brains” of people with Alzheimer’s disease, contributing to cognitive decline.
Around 15 percent of the study group, or 43 participants, had bed partners who witnessed sleep apnea. Those with witnessed apneas had about 4.5 percent higher levels of tau in the entorhinal cortex than those observed in peaceful sleep. To minimize the impact of “confounding variables,” researchers accounted for several other factors that affect tau levels in the brain: age, sex, education, cardiovascular risk and other sleep complaints.
The bottom line: Yes, there’s a link between snoring, apnea, tau and Alzheimer’s — “but it’s a chicken-and-egg problem,” Carvalho says, pointing to the conundrum of “which comes first” as an underlying cause.
Does sleep apnea cause an accumulation of tau, a toxic protein that forms into tangles in the brains of people with Alzheimer’s disease? Or does the accumulation of tau in certain areas spur sleep apnea?
Well, brace yourself to remain patient at bedtime, long-suffering, sleepy spouses, because “longer studies are now needed to solve this problem,” Carvalho says.