Sleep disruptions can have long-lasting effects on the brain. Adding more evidence to this link, researchers have now identified that a common sleep disorder could contribute to an increased risk of developing dementia in older adults, particularly in women.

A recent study published in Sleep Advances revealed a concerning sex-specific link between obstructive sleep apnea and the risk of dementia.

Obstructive sleep apnea occurs when breathing stops abruptly between sleep, triggering a survival reflex to restart breathing. This results in disrupted sleep and symptoms such as snoring, fatigue, daytime sleepiness, and mood issues.

To understand the link between obstructive sleep apnea and dementia risk, researchers analyzed 18,815 U.S. adults aged 50 and older who were part of the Health and Retirement Study. The participants were free from dementia at the start of the study. During the 10-year follow-up period, obstructive sleep apnea was identified through self-reports or screening, and dementia cases were identified based on cognitive tests.

The results showed that obstructive sleep apnea was associated with a higher cumulative incidence of dementia for both women and men between the ages of 60 and 84.

However, by age 80, women with obstructive sleep apnea had a 4.7% higher incidence of dementia than those without it, while men with the condition showed a 2.5% increase. This suggests that sleep apnea raises dementia risk more significantly in women than in men.

"Our findings offer new insight into the role of a treatable sleep disorder on long-term cognitive health at the population level for both women and men," said first author Dr.Tiffany J. Braley in a news release.

Based on the findings, researchers say that obstructive sleep apnea is a "potentially modifiable yet frequently overlooked risk factor for dementia onset." They suggest that people with sleep disorders should be screened for dementia.

Although the study has not investigated the reasons for the sex-specific differences in dementia risk linked to sleep apnea, the researchers suggest a few possible explanations.

One reason could be that women with dementia are at a greater risk of cardiovascular disease and insomnia, both risk factors affecting cognitive function.

"Estrogen starts to decline as women transition to menopause, which can impact their brains. 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 underdiagnosed. We need more epidemiologic studies to better understand how sleep disorders in women impact their cognitive health," Galit Levi Dunietz, co-author of the study said.

Read more