Poor sleep patterns in early midlife may accelerate brain aging

Key takeaways:

• Having two to three poor sleep characteristics was linked to a 2-year increase in brain age.
• Poor sleep quality and insomnia symptoms were associated with accelerated brain aging.

Poor sleep patterns in early midlife appeared to be associated with advanced brain age in late midlife, suggesting the importance of early sleep interventions to preserve brain health, according to study results.

“Sleep problems have been linked in previous research to poor thinking and memory skills later in life, putting people at higher risk for dementia,” Clémence Cavaillès, PhD, MS, postdoctoral researcher in epidemiology in the department of psychiatry and behavioral sciences at the University of California, San Francisco, said in a related American Academy of Neurology press release.

Previous studies have typically focused on older adults, although Alzheimer pathology begins in the brain several decades before symptoms occur, the researchers wrote in the study published in Neurology, the medical journal of the AAN.

This inspired Cavaillès and colleagues to investigate how poor sleep characteristics and changes in early midlife affected brain health in late midlife.

The prospective cohort study involved 589 participants (mean age, 40.4 ± 3.4 years; 53% women; 39% Black) recruited from the Coronary Artery Risk Development in Young Adults study who had baseline sleep data and MRI scans. Participants completed questionnaires that researchers used to assess sleep duration, sleep quality and whether patients had difficulty initiating and maintaining sleep, early morning awakening and daytime sleepiness.

The researchers divided the participants into groups based on number of poor sleep characteristics (0-1, 2-3 or 3+) and used brain MRIs participants underwent 15 years later to determine brain age through a machine learning approach based on age-related atrophy.

The researchers found that 70% of participants reported having one poor sleep characteristic, 22% reported two to three and 8% reported more than three.

After mean follow-up of 15 ± 0.5 years, the participants’ mean brain age was 54.3 ±7.4 years and mean chronological age was 55.3 ± 3.5 years.

Overall, results of multivariable linear regression analyses showed that having more than one poor sleep characteristic was associated with older brain age, including by 1.61 years for two to three characteristics (B = 1.61, 95% CI, 0.28-2.93); and 2.6 years for three or more characteristics (B = 2.64, 95% CI, 0.59-4.69) compared with participants with one or fewer poor sleep characteristics.

Further, the researchers found that when examining individual sleep characteristics, older brain age could be linked to bad sleep quality (B = 1.84; 95% CI, 0.26-3.43), difficulty initiating sleep (B = 2.38; 95% CI, 0.75-4.02), difficulty maintaining sleep (B = 1.14; 95% CI, 0.03-2.25) and early morning awakening (B = 2.45; 95% CI, 0.99-3.9).

These findings were supported by a subsample of 566 participants with repeated sleep data 5 years after baseline. Specifically, researchers found increased brain age was linked to persistent bad sleep quality (2.8 years), difficulty initiating sleep (3.8 years), difficulty maintaining sleep (1.8 years), early morning awakening (3.8 years) and daytime sleepiness (2.4 years).

The researchers noted several limitations to this study, including the potential for misclassification bias due to using self-reported sleep measures and limited generalizability of the findings due to the selectivity of the study sample.

“Our finding suggests that poor sleep in early midlife may have effects on brain health already by midlife,” Cavaillès and colleagues wrote. “Moreover, advanced brain aging has been associated with worse cognitive functions and AD-related atrophy patterns.”

The findings suggest that poor sleep could be targeted by early interventions, according to the researchers.

“Future research should focus on finding new ways to improve sleep quality and investigating the long-term impact of sleep on brain health in younger people,” study author Kristine Yaffe, MD, professor of psychiatry, neurology and epidemiology and director of Center for Population Brain Health at the University of California, San Francisco, said in the release.

Reference:

• Could poor sleep in middle age speed up brain aging? https://www.aan.com/PressRoom/Home/PressRelease/5209. Published Oct. 23, 2024. Accessed Oct. 30, 2024.