Why How Much You Sleep Could Affect Your Risk for Alzheimer's Disease

Having sleep problems could mean you're more at risk for developing Alzheimer's disease than those who don't have such issues, according to new research published in Neurology Wednesday.

This isn't the first time research has linked sleep troubles with an increase in the biological hallmarks of Alzheimer's disease, though this study builds on previous evidence.

"Disrupted sleep or lack of sleep may lead to amyloid plaque buildup because the brain's clearance system kicks into action during sleep," study author Barbara B. Bendlin of the University of Wisconsin-Madison said in a statement. "Our study looked not only for amyloid but for other biological markers in the spinal fluid as well." People with Alzheimer's disease have plaques and tangles in their brain, made up of amyloid – a protein that can develop into plaques – and tau – one that can develop into tangles.

Researchers examined 101 people for the study, all with "normal" thinking and memory skills but thought to have a risk for developing Alzheimer's. Participants both responded to survey questions about sleep quality and gave spinal fluid samples for the Alzheimer's marker testing.

Those with worse sleep quality, daytime sleepiness and more sleep problems also were the ones with more of the biological markers of Alzheimer's disease like amyloid, tau and brain cell damage.

As for what makes sleep so important: "In the deepest stage of sleep, the brain cleans itself out of plaque and other toxic materials that trigger Alzheimer's disease," Rudolph Tanzi of Massachusetts General Hospital told CNN. "This reduces brain inflammation and is entirely consistent with this exciting new study."

One clear caveat of the study is that people self-reported their sleep problems. Researchers recommend further study on the association between the biomarkers and sleep.

That said, Bendlin did offer a more optimistic take on the implications of the study.

"There are already many effective ways to improve sleep," Bendlin added. "It may be possible that early intervention for people at risk of Alzheimer's disease may prevent or delay the onset of the disease."

In the U.S., Alzheimer's is the sixth leading cause of death, affecting more than 5 million Americans. That number could increase to as many as 16 million by 2050, according to the Alzheimer's Association.

Also out Wednesday, a new study found that more than 1.2 million people in England and Wales will have dementia by the year 2040 – a 57 percent uptick from 2016.