Sleep apnea linked to higher risk of dementia in older adults, especially women: Study

Obstructive sleep apnea (OSA), a common but often underdiagnosed sleep disorder, contributes to the development of dementia in adults, especially women, according to a recent study from Michigan Medicine. Researchers analyzed survey and cognitive screening data from more than 18,500 people to assess the impact of known or suspected sleep apnea on dementia risk.

Obstructive sleep apnea, characterized by interruptions or restriction of breathing during sleep, affects many adults.

In India, at least 10.4 lakh people suffer from sleep apnea, according to government data. The study found that for adults ages 50 and older, awareness of sleep apnea or its symptoms was linked to an increased likelihood of being diagnosed with dementia in later years.

Although the overall increase in sleep apnea-related dementia diagnoses did not exceed 5%, the findings remained statistically significant even after adjusting for several risk factors such as race and education. Specifically, women who knew or suspected sleep apnea were more likely than men to be diagnosed with dementia. While the rate of being diagnosed with dementia increases as women get older, this rate decreases for men.

The study’s first author and neuroscientist at the University of Michigan Health, Dr. “Our findings provide insight into the role of a treatable sleep disorder on long-term cognitive health at the population level for both women and men,” said Tiffany J. Braley.

The research, published in the journal SLEEP Advances, underlines the need to increase awareness and diagnosis of sleep apnea, especially among older women.

Researchers suggest there are several reasons for the increased risk among women, including a higher prevalence of cardiovascular disease and insomnia, both of which can negatively impact cognitive function.

Co-author of the study, Dr. Galit Levi Dunietz noted that the decline in estrogen during menopause may also play a role, making women more susceptible to mood changes that can lead to memory, sleep and cognitive decline.

A 2024 report by the Lancet Commission mentioned sleep apnea as a potential contributing factor to dementia, although it is not officially classified as a risk factor. The commission recommended that dementia screening questions be considered in individuals diagnosed with sleep disorders.

Another co-author of the study, Dr. Ronald D. Chervin cautioned that although the research suggests a correlation, it cannot establish definitive causality between sleep apnea and dementia. He emphasized that randomized studies are needed to determine the effects of sleep apnea treatment on cognitive outcomes.

The results of this study are important because untreated sleep apnea can lead to cognitive decline and exacerbate other risk factors for dementia, such as cardiovascular and mental health problems. Dr. Underlining the need for early diagnosis and treatment, Braley said: “Obstructive sleep apnea and the resulting sleep deprivation and fragmentation are associated with inflammatory changes in the brain that can contribute to cognitive impairment.”

As understanding of sleep disorders and their long-term effects on health continues to evolve, the findings from this study call for increased attention from both healthcare providers and patients to recognizing and addressing obstructive sleep apnea to protect cognitive health.