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Sleep and Dementia | What New Research Says About Sleep Problems and Dementia Risk

Sleep and Dementia | What New Research Says About Sleep Problems and Dementia Risk

Sleep and dementia have long been studied in relation to one another by researchers looking to better understand what contributes to a higher risk of dementia. But what’s the verdict - can a lack of sleep cause dementia? Two new research studies may hold the answer.

If you keep an eye on health headlines, you’ve probably seen a lot of talk about sleep and dementia lately. That’s because two new landmark studies published in Nature Communications and the Journal of Sleep Research have unearthed some intriguing connections between sleep and dementia risk that everybody over the age of 50 should be aware of.

Since complex research studies like these can be dense and difficult to traverse on your own, we’re going to break down the science in simple terms here today. From the new data we have about sleep and dementia, to the reasons why scientists believe the two are closely related, and even some research-backed tips on how you can improve your own sleep health, here’s everything that you should know about sleep and dementia.

sleep and dementia

The Stunning New Discoveries About Sleep and Dementia

You may already be familiar with the fact that people with dementia experience sleep problems such as insomnia, nighttime wandering, and daytime sleepiness. This has caused researchers to have a heightened interest in the relationship between sleep and dementia, but always posed something of a “chicken and egg” question. Does poor sleep increase the risk of dementia, or does dementia simply affect sleep after the fact? The two new studies we’re looking at sought to explore exactly that.

The Harvard Medical School Study

The first, published in the Journal of Sleep Research, was conducted by researchers at Harvard Medical School, and analyzed data collected by the National Health and Aging Trends Study (NHATS).1 This data followed over 6,000 medicare beneficiaries from 2011 to 2018 using in person interviews which, among other things, gathered information about their sleep habits.

Researchers focused on individuals in the highest risk category - those who reported sleep issues "most nights or almost every night." These sleep issues were broken into two categories: trouble falling asleep and frequent nighttime awakenings. As researchers compared these data points against the individuals’ medical records, correlations between sleep and dementia became clear:

  • Those who reported having trouble falling asleep on a regular basis had a 49% increased risk of dementia.
  • Individuals who routinely woke up during the night and had problems falling back asleep had a 39% increased risk.
  • People who experience both trouble falling asleep and constant waking had a 56% increased risk.

The Nature Study

Another recent study published in Nature Communications, an offshoot of the prestigious scientific journal Nature, gives us an even broader picture of sleep and dementia. In this study led by Dr. Séverine Sabia of Inserm and University College London, 8,000 people were examined over the course of over 25 years, beginning at age 50.

The participants were interviewed periodically throughout the years about how many hours they slept per night, and wearable devices were used to verify these reports. Ultimately, 521 of the study’s participants were diagnosed with dementia at an average age of 77. After analyzing the data, researchers concluded that people in their 50s and 60s getting six hours of sleep or less were at greater risk of developing dementia later in life, with the participants getting insufficient sleep being 30% more likely to develop dementia than those sleeping 7 hours or more.

What Might Explain The Link Between Sleep And Dementia?

While these studies can’t provide a definitive “yes” to the question “can lack of sleep cause dementia”, they certainly illustrate a strong correlation that suggests it may. That begs another question of why sleep and dementia risk seem to be related in this way and, once again, we can turn to some really interesting research.

There are two proteins found in the brain that scientists consider to be hallmarks of Alzheimer’s disease and dementia: beta amyloid and tau. These essentially form “plaque” in the brain, which is responsible for disrupting neural communication and ultimately killing brain cells to result in the disruptions that Alzheimer’s and dementia cause.

A 2017 study published in the journal Brain investigated how sleep affects the accumulation of these proteins in the brain, and discovered some important connections3:

  • Sleeping poorly for just one night was enough to produce an abundance of beta amyloid plaques in healthy middle-aged adults.
  • A week of disrupted sleep resulted in an increase of tau protein, which is now considered to be a more accurate predictor of Alzheimer’s associated neurodegeneration than beta amyloid.4

These findings were supported by yet another 2017 study that found subjects with sleep issues were more likely to exhibit issues caused by tau, brain cell damage, and brain cell inflammation.5 In an interview with CNN, one of the study’s co-authors said, “Our findings align with the idea that worse sleep may contribute to the accumulation of Alzheimer's-related proteins in the brain.”

How To Improve Your Sleep According to the Experts

Having taken an in-depth look at what the scientific community has come to understand about sleep and dementia, you might be wondering what you can do to improve your own sleep habits. According to the CDC, the average adult needs at least 7 hours per night, which is right in line with the findings of Dr. Sabia’s study.

Here are a few good habits to improve your sleep, according to the CDC:

  • Set a consistent schedule for when you go to bed and wake up, including on the weekends.
  • Give yourself a good environment to sleep in. Make sure your bedroom is quiet, dark, relaxing, and at a comfortable temperature.
  • Avoid having electronic devices in your sleeping environment, and stop using them a few hours before bedtime.
  • Try not to have any large meals, caffeine, or alcohol in the evening.
  • Avoid all use of tobacco and nicotine.
  • Exercise! Not only is it great for all areas of your health; it can help you fall asleep more quickly at night.

Of course, it can’t be said that any of these practices will directly impact your risk for developing dementia, but healthy sleep is an important part of total wellness, nonetheless.

Understanding the constantly unfolding connection between sleep and dementia is undoubtedly a great tool to have in your wellness knowledge base. These recent studies truly shine a fascinating light on how sleep and dementia risk may be linked, and might result in some great new ways for doctors and scientists to approach this important issue. If you have any concerns about your own neurological health, make sure to talk with your doctor.

If you’d like to learn about some general tips to help support a healthy brain, make sure to check out our quick and easy article on the subject. You can also follow us on Facebook and Instagram to keep up with the latest health and wellness news similar to the exploration of sleep and dementia you just read.

  1. Robbins R, Weaver MD, Barger LK, Wang W, Quan SF, Czeisler CA. Sleep difficulties, incident dementia and all-cause mortality among older adults across 8 years: Findings from the National Health and Aging Trends Study. J Sleep Res. 2021 Jun 2:e13395. doi: 10.1111/jsr.13395. Epub ahead of print. PMID: 34080234.
  2. Sabia S, Fayosse A, Dumurgier J, van Hees VT, Paquet C, Sommerlad A, Kivimäki M, Dugravot A, Singh-Manoux A. Association of sleep duration in middle and old age with incidence of dementia. Nat Commun. 2021 Apr 20;12(1):2289. doi: 10.1038/s41467-021-22354-2. PMID: 33879784; PMCID: PMC8058039.
  3. Yo-El S Ju, Sharon J Ooms, Courtney Sutphen, Shannon L. Macauley, Margaret A. Zangrilli, Gina Jerome, Anne M. Fagan, Emmanuel Mignot, John M. Zempel, Jurgen A.H.R. Claassen, David M. Holtzman, Slow wave sleep disruption increases cerebrospinal fluid amyloid-β levels, Brain, Volume 140, Issue 8, August 2017, Pages 2104–2111,
  5. Kate E. Sprecher, Rebecca L. Koscik, Cynthia M. Carlsson, Henrik Zetterberg, Kaj Blennow, Ozioma C. Okonkwo, Mark A. Sager, Sanjay Asthana, Sterling C. Johnson, Ruth M. Benca, Barbara B. Bendlin Neurology Aug 2017, 89 (5) 445-453; DOI: 10.1212/WNL.0000000000004171
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