Your insomnia may be increasing your risk for dementia

By Jason Wooden, PhD | Last updated:  October 9, 2024

Growing evidence links poor sleep to dementia

We’ve all woken up with that groggy feeling in the morning after a bad night of sleep.  It sure makes it hard to focus and get things done during the day, but did you know that your poor sleep could be hurting you down the road?

People with dementia have significant declines in cognitive abilities.  While symptoms can vary, they often have memory issues and find it harder to focus making it more difficult to perform everyday tasks.

According to the World Health Organization, there are nearly 10 million new cases of dementia every year.

Known risk factors for dementia include high cholesterol, diabetes, cardiovascular disease, obesity, depression, smoking, and alcohol use.

However, according to the US Centers for Disease Control and Prevention, age is the biggest risk factor. 

Your risk for Alzheimer’s disease, the most common cause of dementia, doubles every five years once you hit age 65.

Recently, a research study has highlighted a new risk factor for dementia – insomnia.

Taiwanese researchers compared over 50,000 insomnia patients with a control group of 58,715 individuals.

After a 3 year follow up, they found that the insomnia patients had double the risk for developing dementia. 

The risk for younger patients was even higher.

More recently, researchers in the UK tracked nearly 8,000 individuals starting at age 50.   Over the course of the study, 521 participants were diagnosed with dementia.

Analysis revealed that individuals in their 50s and 60s who slept for 6 or less hours at night were 30% more likely to be diagnosed with dementia!

While these findings agree with other studies that have found that people who get less deep sleep have a greater risk for dementia, they don’t explain how insomnia affects cognitive decline down the road.

So, what’s the connection?

Insomnia has been linked to other age-related conditions such as hypertension, diabetes, and cardiovascular disease.

However, what could be the link with dementia?

Dementia is a disease process in which the brain cells degenerate.  One possibility is the growing evidence that sleep is essential for maintaining a healthy brain.

Some research suggests that during sleep the brain washes out harmful proteins and waste products. 

Of note is the Beta-amyloid protein which has been found to clump together and disrupt the function of neurons in people with Alzheimer’s.

Researchers have recently found that just one night of sleep deprivation can increase the buildup of Beta-amyloid in the brain.  Taken all together, what this could mean is that insomnia over the long-term can lead to the build up waste products which damage brain cells and further hasten cognitive decline.

While it’s not clear why younger patients have an even greater risk for dementia after just 3 years, the Taiwanese study does highlight the importance of sleep given that insomnia has been linked to so many other health issues.

Nonetheless, if you want to stay mentally sharp down the road, be sure to get great sleep every night.

And remember when it comes to sleep, it not just how long you sleep but also how well.

4 Tips to Stay Mentally Sharp:

Sleep hygiene basics

10 reasons why sleep is NOT a waste of time

More ideas to fall asleep faster

Common sleep disorders

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3. A Paravascular Pathway Facilitates CSF Flow Through the Brain Parenchyma and the Clearance of Interstitial Solutes, Including Amyloid Beta.  Science Translational Medicine, 2012, volume 4, issue 147.

4. Beta-Amyloid accumulation in the human brain after one night of sleep deprivation.  Proceedings of the National Academy of Sciences U S A, 2018, volume 115, issue 17, pages 4483-4488.