Alzheimer’s disease development linked to poor sleep; Degenerative disease may also negatively affect sleep

Poor sleep may lead to Alzheimer’s, especially for those who carry the risk of the degenerative disease. Lead scientist Dr. Barbara Bendlin of the University of Wisconsin-Madison in the US said that previous studies had also shown the influence of sleep on the development progression of the disease in various ways.

Researchers involved in the study conducted spinal fluid tests on 101 participants. Their average age was 63 years, and they had a family history of Alzheimer’s or were carrying a gene linked to the condition. Those participants suffering from daytime drowsiness, and those who reported poor quality of sleep, had more biological markers for the disease than those who did not report sleep problems.

Dr. Bendlin explained that the study not only looked for amyloid but also biological markers in the participants’ spinal fluid. Lack of sleep or disrupted sleep could lead to amyloid plaque deposits in the brain as the clearance system kicks into action during sleeping. The scientists looked for signs of toxic brain protein clumps, tau tangles and beta-amyloid. The toxic proteins have already been linked to causing Alzheimer’s. Tau tangles, meanwhile, are protein knots within nerve cells also associated with the degenerative disease.

Researchers, however, stated that not all participants involved in the study had spinal fluid abnormalities. According to them, they did not find a link between biological markers for Alzheimer’s disease and obstructive sleep apnoea.

The study has been published in the online issue of Neurology®, the medical journal of the American Academy of Neurology. Research remained intact even after taking into account other factors such as body mass index, symptoms of depression, level of education and medicine use. It is still unclear whether sleep affects the development of Alzheimer’s or whether the disease negatively affects quality of sleep.

“It's important to identify modifiable risk factors for Alzheimer's given that estimates suggest that delaying the onset of Alzheimer's disease in people by a mere five years could reduce the number of cases we see in the next 30 years by 5.7 million and save US$367 billion (AU$480 billion) in health care spending... There are already many effective ways to improve sleep. It may be possible that early intervention for people at risk of Alzheimer's disease may prevent or delay the onset of the disease,” Dr. Endlin said in a statement. Stay tuned for more updates on studies on Alzheimer’s disease.