Poor sleep patterns in older women linked to cognitive impairment, dementia
Key takeaways:
- Older women with increasing daytime sleepiness had roughly double the risk for dementia vs. those with stable sleep.
- The results highlight the need for more research in this area.
In a cohort of older community-dwelling women, unfavorable sleep patterns were associated with cognitive impairment and higher dementia risk, according to data published in Neurology.
“Sleep is essential for cognitive health, as it allows the brain to rest and rejuvenate, enhancing our ability to think clearly and remember information,” Yue Leng, PhD, associate professor in the department of psychiatry in the Weill Institute for Neurosciences at the University of California, San Francisco, said in a related release. “However, little is known about how changes in sleep and cognition are connected over time and how these changes relate to dementia risk in the later decades of life.”
Leng and colleagues examined whether alterations in the 24-hour sleep-wake cycle are associated with mild cognitive impairment (MCI) and dementia among community-dwelling women aged 65 years and over, a demographic they called the “oldest old.”
Their study included 733 ambulatory women (mean baseline age, 82.5 years) at three U.S.-based sites who were enrolled in the Study of Osteoporotic Fractures without hip replacements, MCI or dementia at baseline. The participants completed wrist-based actigraphy over a 3-day period so the researchers could track sleep-related activities. The participants also underwent cognitive assessment via neuropsychological battery and clinical evaluation at baseline and 5-year follow up.
The researchers analyzed the data from both intervals and identified profiles for nighttime sleep (sleep duration, sleep efficiency and wake after sleep onset), napping (duration and frequency) and circadian rest-activity rhythms (acrophase, amplitude, mesor and robustness).
Subsequent analysis yielded associations between the different sleep profiles, MCI and dementia risk across 5 years, adjusting for a range of sociodemographic covariates including those taken at baseline.
Leng and colleagues established three different sleep-wake change profiles: stable sleep (n = 321); declining nighttime sleep (n = 256); and increasing sleepiness (n = 156).
According to the results, 164 (22.4%) participants developed MCI and 93 (12.7%) developed dementia by the 5-year follow-up evaluation.
After adjustment for covariates, participants with increasing sleepiness had approximately double the risk for dementia (OR = 2.21; 95% CI, 1.14-4.26) compared with those with stable sleep. Additionally, sleep efficiency, wake after sleep onset, nap duration and nap frequency were individually associated with dementia. Neither sleep-wake change profiles nor individual parameters were associated with MCI, the researchers reported.
“Sleep-wake activity can change drastically in oldest old women,” Leng and colleagues wrote. “Our findings emphasize the importance of a holistic view of multiple dimensions of 24-hour sleep-wake activity and the need for research on the link between longitudinal sleep-wake change and dementia risk.”
In a related editorial, Marino Muxfeldt Bianchin, MD, PhD, and Eduardo Rigon Zimmer, BPharm, MSc, PhD, from the Federal University of Rio Grande do Sul in Brazil, said that, despite the limitations of the study, identifying the impact of sleep behaviors in the “oldest old” was valuable for inclusion of an overlooked demographic.
They added that Leng and colleagues’ study “enhances our understanding of dementia risk factors, highlighting the critical need for continued research on the role of sleep in cognitive health.”
Reference:
Sleepier during the day? For some older people, it’s linked to twice the dementia risk. https://www.aan.com/PressRoom/Home/PressRelease/5246. Published March 19, 2025. Accessed March 19, 2025.
Bianchin MM, Zimmer ER. Neurology. 2025;doi:10.1212/WNL.0000000000213516.