People with obstructive sleep apnea may be more likely to develop dementia, and the risk may be higher for women, a new study has found.

The new research raises questions about how obstructive sleep apnea— which lowers a person’s oxygen levels while they sleep — could affect brain health over time.

“Obstructive sleep apnea is a common, underdiagnosed but treatable condition that is associated with important pathological changes in the brain,” study author. Tiffany Joy Braley, MDassociate professor of neurology and co-founder of the MS Fatigue and Sleep Clinic at University of Michigan Health, said Health. “(These) overlap with many brain changes seen in people with cognitive decline and dementia.”

Beyond simply finding a link between sleep apnea and dementia risk, the researchers found that this association is more pronounced in women. Experts still aren’t sure why this happens, though it could have something to do with women’s already increased risk of cognitive problems.

“There are several reasons why women may be at greater risk of dementia, including their longer life expectancy, differences in health behaviors and social determinants of health“, the author of the study Galit Levi Dunietz, PhD, MPHsaid associate professor in the Department of Neurology and Division of Sleep Medicine at the University of Michigan Health.

The study was published last month in the journal Sleep advances.

Here’s what experts had to say about the link between obstructive sleep apnea and dementia, and how to protect your cognitive health if you have a sleep disorder.

This is not the first study to establish a link between obstructive sleep apnea and dementia, experts said. However, “this new study adds to the conversation by providing (10 years of) longitudinal data on 18,815 subjects.” Nitun Verma, MD, MBAsaid a spokesperson for the American Academy of Sleep Medicine Health.

The research included participants from the Health and Retirement Study (HRS), which is a nationally representative group of US adults. When the study began in 1992, the participants were over 50 years old and all did not suffer from dementia.

The researchers then tracked confirmed cases of dementia among study participants and recorded who was diagnosed with obstructive sleep apnea or reported symptoms.

This allowed the researchers to “determine whether preexisting signs of (obstructive sleep apnea) — even in the absence of a given clinical diagnosis — predict the likelihood of future development of dementia,” Braley said.

This decision to include participants with suspected sleep apnea in the analysis is also significant because many Americans who have the disorder have gone undiagnosed. In fact, it is estimated that about 30 million Americans have sleep apnea, although only about 6 million Americans have received a diagnosis.

Several factors could explain this. First, sleep apnea symptoms often develop gradually and go unnoticed, Verma said. “The most common symptoms, such as snoring and daytime sleepiness, are easily dismissed or attributed to other causes.” In addition, many Americans may not be able to undergo a sleep study, which is required to diagnose the condition, experts said.

After the analysis was completed, the researchers found that by age 80, the incidence of dementia was 4.7% higher among women with confirmed or suspected sleep apnea and 2.5% higher among men with a confirmed or suspected case.

“Compared to adults who did not have known or suspected obstructive sleep apnea, adults with obstructive sleep apnea are at higher risk for future dementia, especially women,” Braley said.

Although not investigated in the study, experts have several theories as to why sleep apnea might influence dementia risk.

First, if you have a sleep disorder, it’s difficult to get good quality sleep. This can raise the risk of cognitive problems.

“Recent evidence suggests that sleep deprivation or insufficient sleep – (both are) consequences of obstructive sleep apnea – are associated with increased accumulation of pathological biomarkers associated with alzheimerBraley said.

Another potential explanation is that sleep apnea and sleep deprivation could alter immune system function, making it harder for the body to get rid of toxic substances in the brain that have been linked to dementia, she added.

As for why the association between sleep apnea and dementia was more pronounced among women compared to men, hormonal differences may play a role, Dunietz explained.

“As women move to menopausethey experience a drop in estrogen that could interact with sleep problems to increase the risk of dementia,” she said.

Lack of access to competent care and gender disparities in healthcare could also be to blame.

“A significant factor is that a woman may be underdiagnosed or misdiagnosed, and this may prolong the duration of suffering from the consequences of untreated (sleep apnea),” Verma said. “Further research is needed to better understand and analyze the relationship.”

The new study underscores the need to seek treatment for obstructive sleep apnea if you suspect you have the condition.

“Identifying and addressing this high-impact and treatable condition could provide another step toward supporting cognitive health,” Braley said.

Common signs of sleep apnea include snoring, daytime sleepiness, fatigue, trouble concentrating, headaches, or waking up frequently in the middle of the night to use the bathroom.

It’s important to remember that there is currently no evidence to suggest that sleep apnea itself causes dementia, he said. Robson Capasso, MDprofessor of otolaryngology and chief of sleep surgery at Stanford Health Care.

“People shouldn’t panic about it,” he said Health.

While more research needs to be done on the link between sleep apnea and brain health in particular, poor sleep is a cause for concern — sleep deprivation has been linked to obesityheart health problems and type 2 diabetes.

So if possible, Capasso said, people should try to reduce or address any modifiable risk factors for sleep apnea, including excessive alcohol consumption, cigarette smoking and obesity.

If you’ve already been diagnosed, it’s important to track your symptoms and talk to your doctor if they don’t improve or get worse, Verma added.

“Early recognition, diagnosis and effective treatment of obstructive sleep apnea is crucial because it can help mitigate negative health outcomes,” he said.