Scientists may have found a link between poor sleep and Alzheimer's disease.

Poor sleep might increase the chances of people at risk of Alzheimer’s developing the disease, according to a study.

Scientists conducted spinal fluid tests on 101 people with an average age of 63 who had a family history of Alzheimer’s or carried a gene linked to the condition.

Participants who reported the worse sleep quality or suffered from daytime drowsiness had more biological markers for Alzheimer’s than those without sleep problems.

The researchers looked for signs of beta-amyloid, clumps of toxic brain protein linked to Alzheimer’s, and “tau tangles”, which are knots of protein within nerve cells that are also associated with the disease.

Lead scientist Dr Barbara Bendlin, of the University of Wisconsin-Madison in the US, said: “Previous evidence has shown that sleep may influence the development or progression of Alzheimer’s disease in various ways.

“For example, disrupted sleep or lack of sleep may lead to amyloid plaque build-up because the brain’s clearance system kicks into action during sleep.

“Our study looked not only for amyloid but for other biological markers in the spinal fluid as well.”

Not everyone with sleep problems in the study had abnormalities in their spinal fluid, the researchers said.

For example, there was no link between biological markers for Alzheimer’s and obstructive sleep apnoea.

The results, reported in the journal Neurology, remained the same after taking into account factors such as medication use, level of education, depressive symptoms or body mass index.

Dr Bendlin said it was unclear if sleep might affect the development of Alzheimer’s or if the disease affects the quality of sleep.

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