Black Older Adults’ Poorer Sleep Quality Linked to Executive Function Decline

Ruijia Chen, ScD

Credit: Boston University, School of Public Health

Sleep quality and sleep medication’s effect on cognitive aging differs by race and ethnicity—a new study showed Black older adults’ poor global sleep quality and sleep medication were linked to greater executive function declines compared to White participants.¹

“Our findings that the associations between sleep medication use and cognitive function were stronger among Black older adults are in contrast to a recent study, which showed that sleep medication use was associated with a higher risk of dementia among White compared to Black older adults,” wrote investigators, led by Ruijia Chen, ScD, from the department of epidemiology at Boston University. “These differences in findings may be attributable to variations in the populations, the prevalence of sleep medication use, or the outcomes assessed (e.g., dementia vs. cognitive decline).”

Copious research explored the cognitive health of older adults by race and ethnicity status, finding African American and Hispanic older adults have a 2-fold greater risk of Alzheimer’s disease and related dementias, compared to other races and ethnicities.² Although health-related inequalities including education, psychosocial stressors, and cardiovascular diseases drive the disparities, proximal mechanisms for the inequities were not explored enough.¹

Thus, Chen and colleagues assessed the prevalence of poor sleep quality and sleep apnea—2 factors that could be modified in old age—based on race and ethnicity to see if sleep affects cognitive aging differently for specific racial groups. Leveraging data from the prospective study, Kaiser Healthy Aging and Diverse Life Experiences, participants (n = 1690) had a mean age of 75.7 years and were Asian, Black, Latino, and White. Participants were eligible if they were ≥ 65 years old on January 1, 2017, spoke English or Spanish, and previously participated in the Kaiser Permanente multiphasic health checkup exams between 1964 and 1985.

More than half (59.4%) of participants were female, 59.2% had central adiposity, and 48.2% had a college degree or higher. Black participants reported worse sleep quality and sleep apnea than Asian, Latino, or White participants. Moreover, despite White participants reporting better sleep quality than Black, Latino, or Asian participants, they were most likely to use sleep medication.

Participants completed a modified Pittsburgh Sleep Quality Index to evaluate subjective sleep quality, latency, duration, disturbances, sleep medication use, and daytime dysfunction. To measure sleep apnea risk, participants answered questions about snoring, tiredness, and whether sleep apnea was observed. Executive function and verbal episodic memory were assessed 3 times over a mean of 2.7 years with the Spanish and English Neuropsychological Assessment Scale.

They found shorter sleep duration, frequent difficulty falling asleep, and frequent medication use were linked to worse executive function. Additionally, more difficulty falling asleep and frequent sleep medication use was linked to worse verbal episodic memory. Participants had the greatest cognitive scores when they received roughly 7 hours of sleep.

Investigators found a greater sleep apnea risk was linked to quicker declines in verbal episodic memory (sleep apnea = − 0.02; 95% confidence interval [CI], −0.04 to −0.001) but not executive function. In contrast, worse sleep quality was linked with reduced levels—and quicker decline—in executive function (95% CI, -0.03 to -0.005) but not with verbal episodic memory.

However, race and ethnicity modified the associations. After adjusting for race/ethnicity, Black participants’ poorer global sleep quality (sleep time = -0.02; 95% CI, = 0.02 to -0.01) was linked to a greater effect on executive function decline than White participants.

Additionally, sleep medication use was linked with quicker executive function declines (sleep time = -0.05; 95% CI, -0.07 to -0.03) and verbal episodic memory (sleep time = -0.04; 95% CI, --0.07 to -0.02) for Black participants compared to White participants.

As for specific aspects of sleep quality, investigators noted differences in executive function in Black participants vs. White participants (-0.03; 95% CI, -0.06 to -0.001) and sleep medication use ( -0.06; 95% CI, -0.09 to -0.02). They also observed differences in verbal episodic memory (-0.05; 95% CI, -0.08 to -0.005) and subjective sleep quality (-0.07; 95% CI, -0.12 to -0.02).

Limitations highlighted by the investigators included self-reported sleep quality and sleep apnea data, the longitudinal design, not having information on the type, dosage, and duration of sleep medication use, no data on the use of sleep treatment such as continuous positive airway pressure, and the study did not allow them to identify associations between subgroups of the Hispanic/Latino or Asian populations.

“Our study represents an important step toward unraveling the heterogeneity in the associations of sleep quality and sleep apnea risk with cognitive functioning,” investigators concluded. “If our findings are supported by other studies, sleep quality may emerge as an important modifiable factor for improving cognitive functioning among Black older adults, potentially narrowing racial disparities in cognitive decline.”

^References

1. ^{Chen R, Wang J, Pederson AM, et al. Evaluation of racial and ethnic heterogeneity in the associations of sleep quality and sleep apnea risk with cognitive function and cognitive decline. Alzheimers Dement (N Y). 2024;10(1):e12441. Published 2024 Feb 11. doi:10.1002/trc2.12441}
2. ^{Daniel EV, Kleiman MJ, Galvin JE. Exploring Reasons for Differential Vulnerability and Alzheimer's Disease Risk in Racial and Ethnic Minorities. J Alzheimers Dis. 2023;91(1):495-506. doi:10.3233/JAD-220959}