Tossing and turning all night and walking around in a daily fog? Poor quality sleep and daytime drowsiness may increase the risk of developing Alzheimer’s disease, according to a new study.
The self-reported study examined 101 subjects, all cognitively normal and with an average age of 63. After they completed sleep questionnaires, the subjects submitted to a spinal tap where their spinal fluids were analyzed to look for the presence of indicators of the plaques and tangles that are characteristic of Alzheimer’s. The researchers concluded that poor sleep quality, sleep problems and daytime sleepiness were associated with increased indicators of the disease.
While the association between the lack of sleep and dementia is not 100 percent clear, several animal studies have found that during sleep, the brain’s capacity to clear toxins like beta amyloid ― the toxic protein that forms plaque in the brains of those with Alzheimer’s ― improves. It is possible that this also happens in humans as well. Depositing amyloid in brain tissue is the first known preclinical stage of Alzheimer’s and happens well before any signs of dementia begin.
All participants in the sleep study had known risk factors for Alzheimer’s, such as family history or evidence of the APOE gene, which is associated with a greater chance of developing the disease. Each person rated the amount they slept, their sleep quality and any trouble sleeping, along with daytime drowsiness and naps.
“Participants in our study were willing to undergo a lumbar puncture to move research on Alzheimer’s disease forward,” said senior study author Barbara Bendlin of the Wisconsin Alzheimer’s Disease Research Center. “Analyzing this fluid allowed us to look at markers related to Alzheimer’s disease such as plaques and tangles, as well as markers of inflammation and nerve cell damage.”
“Not everyone with sleep problems is destined to develop Alzheimer’s disease.” Bendlin, who is an associate professor of medicine at the University of Wisconsin School of Medicine and Public Health, told The New York Times. “We’re looking at groups of people, and over the whole group we find the association of poor sleep with the markers of Alzheimer’s. But when you look at individuals, not everyone shows that pattern.”
This latest study adds to a growing body of research showing that disturbed sleep could actually be a cause of dementia. Other studies have shown a connection between chronic sleep disruption and the development of amyloid plaques. The research in mice showed that mice who slept well reduced their levels of beta amyloid, effectively clearing the toxin from their brains.
One of the limitations of this new study was that the sleep problems were self-reported. Bendlin and her colleagues are recruiting people at risk for Alzheimer’s to be studied in a sleep lab, where they can take objective measurements.
“If it turns out to be the case that an intervention which improves sleep also results in less amyloid being deposited in the brain, that would provide strong support for implementing interventions before people start to show cognitive decline associated with Alzheimer’s disease,” she said.
But before you ask your doctor for sleeping pills, Bendlin also told HuffPost, “We don’t yet know if sleep medication has an effect on amyloid. The next step will be to further query these relationships using objective sleep measures.”