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

A common yet frequently underdiagnosed sleep disorder, obstructive sleep apnea (OSA), contributes to the development of dementia in adults, particularly women, according to a recent study from Michigan Medicine. Researchers analysed survey and cognitive screening data from over 18,500 individuals to assess the impact of known or suspected sleep apnea on dementia risk.

Obstructive sleep apnoea, characterised by episodes of disrupted or restricted breathing during sleep, affects many adults.

In India, as per the government data, at least 10.4 lakh people suffer from sleep apnea. For adults aged 50 and older, the study found that having known sleep apnoea or its symptoms was linked to an increased likelihood of receiving a dementia diagnosis in subsequent years.

Although the overall increase in dementia diagnoses associated with sleep apnoea did not exceed 5%, the findings remained statistically significant even after adjusting for various risk factors, including race and education. Notably, women were found to be more likely than men to be diagnosed with dementia when they had known or suspected sleep apnea. As women aged, the rate of dementia diagnoses increased, while it decreased for men.

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

The research, published in SLEEP Advances, highlights a need for increased awareness and diagnosis of sleep apnea, especially among older women.

Researchers suggest several reasons for the increased risk among women, including the higher prevalence of cardiovascular disease and insomnia, both of which can adversely affect cognitive function.

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

In a 2024 report by the Lancet Commission, sleep apnea was mentioned as a potential contributor to dementia, despite not being classified as an official risk factor. The commission recommended that screening questions for dementia be considered for individuals diagnosed with sleep disorders.

Dr. Ronald D. Chervin, another co-author of the study, cautioned that while the research suggests a correlation, it cannot definitively establish causation between sleep apnea and dementia. He emphasised that randomised trials are needed to determine the effects of sleep apnoea treatment on cognitive outcomes.

The implications of this study are significant, as untreated sleep apnoea can lead to cognitive decline and may exacerbate other risk factors for dementia, such as cardiovascular and mental health issues. Dr. Braley highlighted the need for early diagnosis and treatment, stating, “Obstructive sleep apnea and resultant sleep deprivation and fragmentation are associated with inflammatory changes in the brain that may contribute to cognitive impairment.”

As the 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 professionals and patients in recognising and addressing obstructive sleep apnea to safeguard cognitive health.