Sleep in midlife is a bear for many, but University of California researchers found an important link when the issue continues with age.
Always Tired? This Could Signal Dementia Risk, a Study Just Found
Published on Apr. 08, 2025
Around 6.7 million adults have Alzheimer’s dementia, the most common type of dementia, according to national experts, and sadly, there’s no known cure. However, with advancements in medicine, health professionals have identified major risk factors to better diagnose people exhibiting warning signs of the condition.
According to the Cleveland Clinic, early symptoms of dementia can include short-term memory loss, behavioral changes, and confusion. Now, as a new study reports, regularly feeling fatigued may be a risk factor, too.
In a study to published later in April 2025 in the medical journal Neurology, University of California psychiatry researchers examined 733 women with an average age of around 82 years who were enrolled in the Study of Osteoporotic Fractures. Their sleep activity was measured via wrist device at the start of the study and in a follow-up exam.
These women showed no initial signs of mental decline; however, by the follow-up exam five years later, 124 had mild cognitive impairment and 93 had been diagnosed with dementia.
Reviewing the results of the study, researchers found that women who experienced increasing sleepiness had nearly double the risk of dementia compared to participants who experienced stable sleep. “Increasing sleepiness” was defined by researchers as “large increases in daytime and nighttime sleep duration and quality,” as well as “worsening circadian [rest-activity rhythms.]”
Additionally, sleep efficiency, wake after sleep onset, nap duration, and nap frequency were separately linked to dementia. Changes in nighttime sleep were not.
Researchers concluded that “change in multidimensional 24-hour sleep-wake activity may serve as an early marker or risk factor for dementia” in elderly women. Speaking to MedPage Today, one of the study’s authors, Yue Leng, PhD, shared, “Our findings emphasize the importance of viewing sleep health both holistically and longitudinally.”
It’s unclear whether these findings will lead to future treatments, but by highlighting a new potential risk factor for dementia, it could possibly lead to earlier diagnoses. And if dementia is diagnosed sooner, as U.K.-based organization Alzheimer’s Society notes, patients can receive treatments to manage their symptoms and possibly delay the disease’s progression.
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- New Research: This Age Group Experiences “Even Greater” Dementia Risk from Feeling Left Out
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