Sleep Fragmentation Linked to Worse Cognition in Midlife

WEDNESDAY, Jan. 3, 2024 (HealthDay News) -- High sleep fragmentation among younger adults is associated with worse cognition among middle-aged Black and White men and women, according to a study published online Jan. 3 in Neurology.

Yue Leng, Ph.D., from the University of California in San Francisco, and colleagues examined the association between sleep duration and quality among adults in their mid-30s to late 40s and midlife cognition assessed 11 years later. Sleep duration and quality were assessed objectively and subjectively in 2003 to 2005; midlife cognition was evaluated during 2015 to 2016.

Data were included for 526 participants (58 percent women; 44 percent Black), with a mean age of 40.1 ± 3.6 years at baseline. Overall, 45.6 percent of the participants reported poor sleep, defined as a Pittsburgh Sleep Quality Index global score >5. The researchers found that those in the highest versus the lowest tertile of the sleep fragmentation index had significantly increased odds of poor cognitive performance on the Digit Symbol Substitution Test, fluency, and Montreal Cognitive Assessment test (odds ratios, 2.97, 2.42, and 2.29, respectively) after adjustment for demographics, education, smoking, body mass index, depression, physical activity, hypertension, and diabetes. No difference was seen in the association between sleep fragmentation and cognitive performance by race or sex. No association was seen for objective sleep duration or subjective sleep quality with cognition in midlife.

"Our findings indicate that the quality rather than the quantity of sleep matters most for cognitive health in midlife and that the measures of sleep should go beyond self-report," the authors write.

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