Insomnia can cause a wide variety of health problems, including cognitive dysfunction and diabetes. Now, a study carried out by scientists at the University of Wisconsin-Madison (USA) concludes that another of its possible consequences is Alzheimer’s disease.
“Previous evidence has shown that sleep can influence the development or progression of Alzheimer’s disease in several ways ; for example, interrupted sleep or lack of sleep can lead to the accumulation of amyloid plaque, because the system purification of the brain comes into action during sleep “, clarifies Barbara B. Bendlin, leader of the study that collects the journal Neurology.
The researchers examined 101 people (63 years on average), with normal cognitive abilities but at risk of developing Alzheimer’s disease, either because they had a relative with the disease or because they had the gene for apolipoprotein E , which leans the balance.
The experts asked the participants to answer a questionnaire about the quality of their sleep , at the same time that they had to provide samples of cerebrospinal fluid.
Biological markers for Alzheimer’s include signs of amyloid (which forms plaques) and accumulation of tau protein (which forms tangles). These are “sticky” proteins overproduced in the brains of people with this neurodegenerative disease. Both formations block communication between neurons or obstruct the transport of nutrients to nerve cells , leading to neurodegeneration.
Analysis of the participants’ cerebrospinal fluid showed “signs of amyloid damage, tau and inflammation,” the study states. Thus, people who reported being sleepy during the day, experiencing poor sleep quality, or other related problems had more biomarkers for Alzheimer’s disease in their cerebrospinal fluid than volunteers who had no sleep problems.
The results remained the same even after adjusting for potential confounders , such as sleep medication use, educational level, depression, and body mass index (BMI).
However, the authors note that not all sleep disorders are associated with signs of Alzheimer’s. For example, there was no relationship between cerebrospinal fluid biomarkers and obstructive sleep apnea.
“It is not yet clear if sleep affects the development of the disease or if the disease affects the quality of sleep, so more research is needed to further define the relationship between sleep and these biomarkers,” explains Bendlin.
“It is possible that early intervention in people at risk of Alzheimer’s disease can prevent or delay the onset of the disease,” he says.
Reference: Sleep Problems May Be Early Sign of Alzheimer’s. Neurology, American Academy of Neurology. aan.com/PressRoom/Home/PressRelease/1563
