Increased sleep could increase dementia risk

How much sleep you get could affect your risk for developing dementia, but not for the reason you may think.

Researchers found people who started sleeping more than nine hours a night over the course of a decade more than doubled their risk of developing dementia compared to those who slept nine hours or less, according to a new study published in the journal Neurology. The increased risk was not seen in people who had always slept more than nine hours. 

Researchers speculate that excessive sleep may be a symptom rather than a cause of the brain changes that occur with dementia. Prolonged sleep duration may be a sign of early neurodegeneration and screening for sleeping problems may help identify those at a higher risk of developing dementia. However, researchers say interventions to restrict sleep duration are unlikely to reduce the risk.

“We’re not suggesting you go wake up Grandpa,” said Sudha Seshadri, MD, professor of neurology at Boston University School of Medicine and senior study author to The New York Times. “We think this might be a marker for the risk of dementia, not a cause of the illness. My suspicion is that this is a compensatory mechanism: that at a time when amyloid is building up in the brain, people may be sleeping longer as the body is reacting and trying to remove it from the brain.”

Researchers studied the association between sleep duration and the risk of dementia using data from 2,457 people, average age 72, who were part the Framingham Heart Study. Study participants were asked to self-report how long they typically slept each night.

Participants without a high school degree who slept for more than 9 hours each night had six times the risk of developing dementia in 10 years. Researchers also found those who slept longer had smaller brain volumes. 

Topics: Alzheimer's/Dementia