Why might sleep apnea raise dementia risk?
A common disorder that repeatedly interrupts breathing during sleep is tied to changes in brain structure that are also seen in early dementia.
This was the main finding of new research into obstructive sleep apnea (OSA) in older adults that is now published in the European Respiratory Journal.
In OSA, the soft tissue walls of the throat relax and impede airflow, reducing the amount of oxygen in the blood.
The authors argue that this oxygen reduction may be linked with the thinning of the brain’s “bilateral temporal regions,” as well as an associated type of memory decline.
“Our results suggest,” explains senior study author Sharon L. Naismith, a professor in the School of Psychology at the University of Sydney in Australia, “that we should be screening for OSA in older people.”
Dementia and OSA
Dementia is a syndrome, or group of symptoms, in which there is a progressive decline in ability to think, remember, have conversations, do everyday things, and live independently.
An estimated 50 million people worldwide have dementia, and the annual rate of new cases is just short of 10 million. About 60–70 percent of dementia cases are caused by Alzheimer’s, which is a relentless brain-wasting disease wherein toxic proteins build up in the brain.
In the United States, there are around 5 million people with Alzheimer’s disease, and this figure is expected to nearly triple to 14 million by 2050.
The new study adds to evidence of a link between OSA and dementia. In 2017, for instance, we reported on a study that linked OSA to raised levels of amyloid beta, which is involved in the buildup of toxic protein in the brain in Alzheimer’s disease.
Like dementia, the chances of developing OSA rise with age. In the U.S., it is believed that OSA affects around 18 million adults.
OSA has also been tied to high blood pressure, stroke, heart disease, and even cancer. There is also evidence — from studies that have followed people over time — that OSA is linked to “increased risk of cognitive decline and dementia in the elderly,” note the researchers.