Research

Disrupted sleep

Researchers are investigating a possible link between sleep disruption and markers of Alzheimer's disease

Not getting enough sleep has been linked to slower recovery after a stroke and a higher risk of heart disease. Could it also have an effect on Alzheimer’s disease? The link between sleep disruption and an increased risk of developing Alzheimer’s has been the subject of several recent studies.

Research in mice has shown that amyloid, a protein involved in Alzheimer’s, builds up when the animals are awake and is cleared during sleep. Now researchers are investigating whether disrupted sleep might influence this process in people as well.

Two recent studies, looking at the cerebrospinal fluid (CSF) of people who have disrupted sleep, have shown an increase in biological markers that can indicate the disease’s development. The researchers, from Washington University and the University of Wisconsin, measured levels of amyloid and tau, another important protein in Alzheimer’s disease.

The first study, published in the journal Brain, found that a single night of disrupted sleep resulted in more amyloid, and a week of sleep disruption increased levels of tau.

The second, reported in Neurology, expanded on this by looking at levels of other markers of Alzheimer’s, including signals of inflammation and brain cell activity.

People who reported worse sleep quality tended to have markers in their CSF that were closer to those seen when someone has Alzheimer’s. However, not everyone who reported poor sleep had these kinds of changes.

These studies show a link between sleep and some of the proteins involved in Alzheimer’s, but an increase in amyloid doesn’t necessarily mean a person will go on to develop the disease.

Dr Doug Brown, Director of Research and Development at Alzheimer’s Society, said, ‘While it appears that good quality sleep can help to keep the brain healthy, the exact relationship between sleep and Alzheimer’s risk is still unclear.

‘We need to see further studies that measure sleep in the clinic, and that follow people over a long period of time, to understand whether problems with sleep do actually increase the risk of Alzheimer’s disease.’