Daytime drowsiness a sign of Alzheimer’s?

Growing evidence suggests that lack of sleep may play a role in Alzheimer’s, and that getting enough sleep may be one way to reduce the risk of the memory-robbing disease. (Courtesy Spectrum Health Beat)

Feeling drowsy during the day might mean you have an increased risk for Alzheimer’s, new research suggests.

The long-term study included 123 adults with an average age of 60 when the study began. The findings showed that those who were very sleepy during the day had a nearly threefold increased risk of developing brain deposits of beta-amyloid, a protein associated with Alzheimer’s disease.

The findings add to growing evidence that lack of sleep may play a role in Alzheimer’s, and that getting enough sleep may be one way to reduce the risk of the memory-robbing disease, according to the researchers.

“Factors like diet, exercise and cognitive activity have been widely recognized as important potential targets for Alzheimer’s disease prevention, but sleep hasn’t quite risen to that status—although that may well be changing,” said study leader Adam Spira. He’s an associate professor in the department of mental health at Johns Hopkins Bloomberg School of Public Health, in Baltimore.

“If disturbed sleep contributes to Alzheimer’s disease, we may be able to treat patients with sleep issues to avoid these negative outcomes,” he added in a Hopkins news release.

It’s unclear why daytime sleepiness would be associated with beta-amyloid protein accumulation in the brain, Spira said. And the study did not prove that sleep actually causes beta-amyloid to build up in the brain.

But it may be that poor sleep due to sleep apnea or other factors causes the formation of beta-amyloid through an unknown mechanism, and that these sleep disturbances also cause excessive daytime sleepiness.

“However, we cannot rule out that amyloid plaques that were present at the time of sleep assessment caused the sleepiness,” Spira said.

Animal studies have shown that restricting night-time sleep can lead to more beta-amyloid protein in the brain and spinal fluid, and some human studies have linked poor sleep with greater levels of beta-amyloid in the brain.

Sleep problems are common in Alzheimer’s patients, and beta-amyloid accumulation and related brain changes are thought to harm sleep.

“There is no cure yet for Alzheimer’s disease, so we have to do our best to prevent it. Even if a cure is developed, prevention strategies should be emphasized,” Spira said. “Prioritizing sleep may be one way to help prevent or perhaps slow this condition.”

The study findings were published in the journal Sleep.

Reprinted with permission from Spectrum Health Beat.