By ALICE PARK
Researchers know that a condition as complicated as Alzheimer’s can’t be traced to a single or simple cause. Genetic factors contribute to the degenerative brain disorder that robs people of their memory, and biological process related to aging play a role as well.
But in recent years, scientists have uncovered some behaviors that may also influence Alzheimer’s risk. In the latest study published in JAMA Neurology, a group of them report how sleep — daytime sleepiness, in particular — may be an indicator of Alzheimer’s.
Prashanthi Vemuri, an associate professor of radiology at the Mayo Clinic, and her colleagues wanted to address a puzzling problem in the field. Studies showed that people with Alzheimer’s disease tend to have disrupted sleep, which made sense: biological studies have recently revealed that while the brain sleeps, it clears away deposits of amyloid, the protein that builds up and eventually strangles nerve cells in Alzheimer’s disease. But it wasn’t clear whether the amyloid plaque deposits led to the disrupted sleep, or whether changes in sleep habits contributed to the buildup of the protein.
To find out, Vemuri and her team took advantage of a long-running study of nearly 3,000 older people in the Mayo Clinic Study of Aging, all of whom were recruited from Olmsted County, Minn. For the study, Vemuri selected 283 people without dementia who were over 70, who answered questions about their sleep habits and agreed to have several brain scans for amyloid over the seven-year study period.