Sleep deprivation increases Alzheimer's risk: Radboud hospital

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Researchers from the Radboud University Medical Center in Nijmegen have discovered that chronic sleep deprivation could increase the risk of Alzheimer's. The results of their research has been published in JAMA Neurology journal. 

A normal night's sleep decreases the amount of beta amyloid peptides in the brain. Staying up all night disrupts this natural decrease, and keeps the number of peptides at a constant. These peptides play an important role in the development if Alzheimer's. Chronic sleep deprivation, therefore, increases the risk of developing the condition, the study concludes.

Various studies have used mice to measure the connection between sleep deprivation and the development of Alzheimer's. The build-up of these beta amyloid peptides in the brain is seen as an important cause of Alzheimer's in humans. The Radboud researchers are among those who considered the effect of sleep deprivation among men between 40 and 60 years of age.

In total, 26 healthy men took part in the study. They all stayed one night in the hospital. Half of the study group slept, the others had to remain awake for 34 hours. Their brain activity was monitored throughout the night, and cerebrospinal fluid samples were taken at several stages.

Men who slept normally showed decreasing levels of the peptides, whereas those who did not, showed levels remaining constant. The researchers are considering the relationship between neural activity and the production of beta amyloid peptides. Parts of the brain that show the most activity during waking hours are also the areas where the chance of amyloid deposits are the highest.

"Another possible explanation is that the brain is purified of harmful substances during normal sleep, including beta amyloid. Disrupted sleep can get in the way of this purification", geriatrician Jurgen Claassen says.

"Further research should detect the exact mechanism", says researcher Sharon Ooms, now that the risk factor of sleep deprivation has been pinned down. A follow-up study will investigate sleep deprivation in a separate group of study cases, and over a longer period. At this moment, Ooms is working on a study researching the role of specific deep sleep on the development of Alzheimer's at Washington University School of Medicine.