Sleep apnea and cognitive decline

There’s a connection between sleep-disturbed breathing and dementia risk, especially for those who carry the apolipoprotein-ε4 (APOE-4) genetic tendency toward Alzheimer’s disease, according to research published online in the Annals of the American Thoracic Society journal.

Researchers studied 1,752 older adults (average age of 68) by using sleep studies, sleep questionnaires and cognitive assessments. The data took into account the participant’s race, age, body mass index, education level, smoking status, and chronic conditions such as hypertension, diabetes, benzodiazepine use, and depressive symptoms. Those with sleep apnea, a condition where the breathing slows or stops during sleep, were measured for overnight hypoxemia, where blood oxygen saturation levels dip below 90 percent.

While poor sleep patterns and daytime sleepiness affected memory and attention span in general, those with sleep apnea and its associated low oxygen saturation levels showed worse attention spans and slower cognitive processing speed than others in the study group. Those with the most seriously affected cognition, attention and memory were those who carried the APOE-ε4 allele and had sleep apnea.

The study highlights the potential of using screening and treatment of sleep apnea as a way to reduce risk of dementia, especially in people who carry the APOE-ε4 allele. 

"Our study provides further evidence that sleep-disordered breathing negatively affects attention, processing speed and memory, which are robust predictors of cognitive decline," said senior study author Susan Redline, MD, MPH, Peter C. Farrell Professor of Sleep Medicine, Harvard Medical School, in a release. "Given the lack of effective treatment for Alzheimer's disease, our results support the potential for sleep-disordered breathing screening and treatment as part of a strategy to reduce dementia risk."

Topics: Alzheimer's/Dementia