Suboptimal Sleep Duration Linked to Poor Brain Health

— Middle-age patients with worse sleep saw increased white matter hyperintensities on MRI

by Elizabeth ShortStaff Writer, MedPage Today February 9, 2023

DALLAS — Optimal sleep duration was associated with better neuroimaging brain health profiles among middle-age adults without stroke, according to a cross-sectional study of U.K. Biobank participants.

Compared with optimal sleep duration (7 to <9 hours per night), suboptimal sleep duration was significantly associated with higher white matter hyperintensity presence and volume (P<0.001 for both) after adjusting for age, sex, and race/ethnicity, reported Santiago Clocchiatti-Tuozzo, MD, of Yale School of Medicine in New Haven, Connecticut, during the American Stroke Association’s International Stroke Conference.

Suboptimal sleep was also linked with a significantly worse fractional anisotropy score (P<0.001), but not a mean diffusivity score (P=0.5).

Looking at 48 neuroanatomical tracts, the left and right cerebral peduncles and the left and right superior cerebellar peduncles were the most affected areas of the brain, Clocchiatti-Tuozzo noted.

“We were actually really interested when we saw the results,” he told MedPage Today during a Q&A. “Because they were in the cerebral peduncles and superior cerebellar peduncles, there may be a lot of associations regarding the conglomeration of a lot of axes across the brain, that conglomerate in these pillars, basically, of white matter.”

In two separate models adjusted for age, sex, and race/ethnicity plus cardiovascular risk factors or history of myocardial infarction, results remained similar for the two groups.

This study followed the 2022 decision by the American Heart Association to include sleep duration as part of their cardiovascular health checklist. Their “Life’s Essential 8” is an updated version of their “Life’s Simple 7,” which also includes blood pressure, cholesterol, blood glucose, smoking, exercise, diet, and body mass index (BMI).

For this study, the researchers included 28,899 participants in the optimal sleep group (mean age 55, 46.7% men) and 10,860 participants in the suboptimal sleep group (<7 or>9 hours per night; mean age 55.3, 47.6% men). Across both groups, the majority were never smokers, and mean BMI was 26 to 27. Similar proportions of participants had hyperlipidemia, diabetes, hypertension, and myocardial infarction.

Participants were categorized by sleep duration, with the “best” length of sleep at 7 to <9 hours, followed by 9 to <10 hours, 6 to <7 hours, 5 to <6 or ≥10 hours, 4 to <5 hours, and <4 hours.

Due to the observational nature of the study, a direct causality between length of sleep and markers of brain injury cannot be determined, Clocchiatti-Tuozzo noted. He also pointed out that the study was lacking in racial and ethnic diversity, which is one aspect that should be addressed by further research.

“Two things have to be taken into consideration. The first is validation across other populations, with more diversity in racial and ethnic groups,” he said. “And, of course, that future research is needed to understand if the modification of sleep duration during middle age can actually change, not subclinical, but clinical outcomes in older ages.”