A detailed analysis of data from the A4 study has shown that self-reported sleep duration in adults without cognitive impairment may influence amyloid accumulation and performance in cognitive tests. The Anti-Amyloid Treatment in Asymptomatic Alzheimer's Disease (A4) study is currently being conducted across 67 sites in the US, Canada, Australia and Japan, testing whether a new antibody treatment, solanezumab, can slow memory loss caused by Alzheimer's disease (AD) in cognitively normal individuals aged between 65 and 85. In their JAMA Neurology article, a team of researchers led by Dr. Elizabeth Mormino at the Stanford University School of Medicine performed a cross-sectional analysis of data from 4417 A4 participants, aiming to understand whether self-reported sleep duration might influence amyloid accumulation in the brain, and performance in tests of cognitive and executive function.
When they compared the levels of amyloid accumulation in the brain (as measured by amyloid-PET brain scans) in people reporting different amounts of nightly sleep, they found that people who reported sleeping 6h or less ("short sleep") had higher levels of brain amyloid, and reduced performance in memory domains of cognitive tests. On the other hand, people who reported sleeping 9h or more ("long sleep") had lower performance on a test of executive function, which controls behaviour, attention and task management. The researchers also found associations between lifestyle factors such as alcohol consumption, depressive symptoms and body mass index and self-reported sleep duration. Together, these results suggest that there might be a "sweet spot" for sleep, with both short and long sleep durations being associated with worse outcomes for older adults.
https://jamanetwork.com/journals/jamaneurology/fullarticle/2783664?resultClick=1
