Daytime sleepiness increases risk of Alzheimer’s by fuelling build-ups in the brain


DAYTIME sleepiness causes build-ups in the brain that lead to Alzheimer’s, a new study warns. Even in elderly people who were well into their 70s with no sign of brain disease, researchers found exhaustion could be undo their good health.
Those who felt drowsy during the day, due to poor sleep or waking up in the night, had a greater build-up in their brain of amyloid plaques, which consume the brain, kill cells, and eventually lead to total memory loss. While previous studies have found the same, it was never clear whether amyloid plaques caused the sleep disturbance, or vice versa.
Now, a team led by the Mayo Clinic’s Prashanthi Vemuri have shown in a study published today that sleep itself seems to be a driver of the dangerous plaques that trigger neurodegenerative disease. ‘This study is the first in humans to demonstrate a predictive association between a measure of sleep disturbance at baseline and change in an AD [Alzheimer’s disease] biomarker across multiple points,’ Joseph R. Winer and Bryce A. Mander, of the University of California, wrote in an editorial published with the study in JAMA.
Dr Vermuri and her team studied 283 people aged 70 or older without dementia from the center’s Study of Aging. Each completed surveys assessing sleepiness at baseline and had at least two consecutive imaging scans of their brains from 2009 to 2016.
While the surveys monitored sleeping patterns, the scans tracked the difference in amyloid plaque levels between two scans in different regions of the brain. They found 63 participants (22.3 percent) had excessive daytime sleepiness, and this was associated with increased amyloid plaque accumulation in susceptible regions of the brain.
‘We found that daytime sleepiness was causing more deposition of amyloid in people who are already amyloid positive, so it was influencing the rate of deposition over time,’ Dr Vermuri said. The study fell short of categorically answering why and how sleep has this effect.
However, experts in the field hailed the longitudinal study as a breakthrough, saying the findings hammer home the importance of good sleep to preserve our brain health.