• Posted November 1, 2024

Sleep Apnea Could Raise Dementia Risk, Especially for Women

Sleep apnea appears to increase a person's odds of developing dementia, a new study finds.

The effect seems stronger among women compared to men, noted a research team from the University of Michigan.

Luckily, there are treatments available to help ease sleep apnea, noted study lead author Dr. Tiffany Braley.

“These potential harms caused by sleep apnea, many of which threaten cognitive performance and decline, highlight the importance of early diagnosis and treatment,” said Braley, who directs the Multiple Sclerosis/Neuroimmunology Division at University of Michigan Health in Ann Arbor.

Her team published its findings recently in the journal Sleep Advances.

The study tracked outcomes for 18,500 adults age 50 or older who answered detailed questionnaires on topics including sleep quality, and who also underwent cognitive screening to assess their brain health.

Bradley's team found that having a history of sleep apnea (or its symptoms, in cases where it hadn't been diagnosed) was tied to an up to 5% higher odds of going on to develop dementia.

Five percent may not seem like a lot, but the Michigan team noted that the number held firm even after they had accounted for a lot of other factors that affect dementia risk, such as race and education.

Across the board, a history of sleep apnea appeared to boost dementia risks for women more than men, the study found. It's not yet clear why that gender gap exists.

According to the researchers, sleep apnea in women tends to boost rates of heart disease and/or insomnia, both of which can harm brain function.

Hormonal changes might also come into play, said study co-author Galit Levi Dunietz, an associate professor in the university's division of neurology and sleep medicine.

“Estrogen starts to decline as women transition to menopause, which can impact their brains,” Dunietz said in a university news release. "During that time, they are more prone to memory, sleep and mood changes that may lead to cognitive decline. Sleep apnea increases significantly post-menopause yet remains under-diagnosed."

She believes that "we need more epidemiologic studies to better understand how sleep disorders in women impact their cognitive health."

And for men and women alike, "obstructive sleep apnea and resultant sleep deprivation and fragmentation are also associated with inflammatory changes in the brain that may contribute to cognitive impairment," Braley noted.

The authors stressed that the study wasn't designed to prove that sleep apnea helps cause dementia, only that there's an association.

Proving causality "would likely require a randomized trial, over many years, to compare effects of sleep apnea treatment to the effects of no treatment,"  said study co-author Dr. Ronald Chervin, who directs the Division of Sleep Medicine at U-M Health.

In the meantime, he said, "clinicians and patients, when making decisions about testing for sleep apnea and treating it, should consider the possibility that untreated sleep apnea causes or exacerbates dementia."

More information

Find out your treatment options for sleep apnea at the U.S. National Heart, Lung, and Blood Institute.

SOURCE: University of Michigan, news release, Oct. 29, 2024