Sleep ‘may be particularly important’ for cognition

BETTER sleep was linked to improved global cognition, highlighting its potential role in maintaining cognitive function for aging adults, according to researchers.

Although it is widely known that good sleep is critical for good health, connections between sleep and risk for dementia are not yet understood, Matthew P. Pase, PhD, an associate professor of neurology and epidemiology at Monash University and Harvard University, and colleagues wrote in JAMA Network Open.

Better sleep was linked to improved global cognition, highlighting its potential role in maintaining cognitive function for aging adults, according to researchers.

“Much of the uncertainty surrounding associations between sleep and dementia arises from a paucity of data with long follow-up durations, objective measures of sleep, or consistent data formats and analysis methods to facilitate pooling and sharing of data across studies,” they wrote.

To address this gap, the researchers created the Sleep and Dementia Consortium. The Consortium, which works “to advance sleep research to inform new strategies for dementia prevention,” is composed of five prospective community-based cohorts that have performed methodologically consistent, overnight, home-based polysomnography and neurocognitive assessments, according to the researchers.

Pase and colleagues conducted a cohort study to better understand the associations between obstructive sleep apnea (OSA) and sleep architecture with cognition. They followed 5,946 U.S. adults enrolled in the Sleep and Dementia Consortium’s five population-based cohorts over 5 years.

“By combining across studies, this analysis attempted to address several unanswered questions, including which sleep variables are most robustly associated with cognition, what cognitive domains are most sensitive to differences in sleep, and whether there are systematic differences by key variable,” they wrote.

Pase and colleagues found that mild to severe OSA was linked to worse global cognition (pooled beta per 1% increase = 0.06; 95% CI, 0.11 to 0.01) compared with those who did not have OSA. For moderate to severe OSA, they found comparable results (pooled beta = 0.06; 95% CI, 0.11 to 0.01) vs. those without OSA.

Additionally, across cohorts, higher sleep maintenance efficiency (pooled beta = 0.08; 95% CI, 0.03-0.14) and lower wake after sleep onset (pooled beta per 1-minute increase = 0.07; 95% CI, 0.13 to 0.01) were associated with better global cognition.

However, differences in sleep stages were not linked to cognition.

“These findings suggest that in adults without dementia, sleep consolidation and the absence of sleep apnea may be particularly important for optimizing cognition with aging,” Pase and colleagues concluded.