Evaluation of racial and ethnic heterogeneity in the associations of sleep quality and sleep apnea risk with cognitive function and cognitive decline.

INTRODUCTION: The prevalence of poor sleep quality and sleep apnea differs by race and ethnicity and may contribute to racial disparities in cognitive aging. We investigated whether sleep quality and sleep apnea risk were associated with cognitive function and decline and whether the associations differed by race/ethnicity. METHODS: Participants from the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE; N = 1690; mean age: 75.7 years) study, a cohort of Asian, Black, Latino, and White participants, completed a modified Pittsburgh Sleep Quality Index assessing subjective sleep quality, latency, duration, disturbances, sleep medication use, and daytime dysfunction. Sleep apnea risk was measured by questions about snoring, tiredness, and whether apnea was observed. Executive function and verbal episodic memory were assessed at three time points over an average of 2.7 years with the Spanish and English Neuropsychological Assessment Scale. We fit linear mixed-effect models and stratified analyses by race/ethnicity. RESULTS: Higher sleep apnea risk was associated with faster declines in verbal episodic memory (ß^ sleep apnea = -0.02, 95% confidence interval [CI], -0.04, -0.001) but not in executive function. Poorer sleep quality was associated with lower levels of and faster decline in executive function but not in verbal episodic memory. Race/ethnicity modified these associations: compared to estimated effects among White participants, poorer global sleep quality (ß^ sleep*time = -0.02, 95% CI, -0.02, -0.01) was associated with larger effects on decline in executive function among Black participants. Estimated effects of some individual sleep quality components were also modified by race/ethnicity; for example, sleep medication use was associated with faster declines in executive function (ß^ sleep*time = -0.05, 95% CI, -0.07, -0.03) and verbal episodic memory ß^ sleep*time = -0.04, 95% CI, -0.07, -0.02) among Black participants compared to White participants. DISCUSSION: Observational evidence indicates sleep quality is a promising target for addressing racial/ethnic disparities in cognitive aging, especially among Black older adults. Highlights: Sleep apnea risk was associated with faster declines in verbal episodic memory but not executive function among all participants.Global sleep quality was associated with lower levels of and faster decline in executive function but not verbal episodic memory among all participants.Black older adults were particularly susceptible to the estimated adverse cognitive impacts of global sleep quality, particularly the use of sleep medication.

Greater sleep variance related to decrements in memory performance and event-specific neural similarity: a racially/ethnically diverse lifespan sample.

Successful memory performance depends on overlap between neural representations at encoding and retrieval. With older age, neural similarity, memory performance, and sleep quality decline. Regardless of age, racial/ethnic minorities tend to experience poor sleep, which may contribute to poor memory. Previous studies have not investigated memory performance, neural similarity, sleep quality, and age in diverse participants. Here, we recruited racially/ethnically diverse adults across the lifespan and examined night-to-night sleep quality in relation to memory performance and encoding-retrieval similarity. We employed item-specific, representational similarity analysis (not confounded by effort, word perception, or differences in electroencephalography signal amplitude) to assess neural similarity for intact and recombined paired associates. Greater sleep variance and poorer memory performance were more strongly associated with older age. Interestingly, sleep variance was positively associated with neural similarity for intact pairs. This relationship was stronger with younger age and for racial/ethnic minorities. For recombined pairs, greater sleep variance was associated with reduced neural similarity. Thus, varied sleep may induce greater reliance on familiarity, while consistent sleep may support recollection.

Factors that protect against poor sleep quality in an adult lifespan sample of non-Hispanic Black and non-Hispanic White adults during COVID-19: A cross-sectional study.

Introduction: Stress in relation to the Coronavirus disease 19 pandemic (i.e., COVID-19, COVID stress) may be linked with poor sleep quality. The association between stress that is specific to the COVID-19 pandemic and sleep quality has been understudied, particularly in racially diverse people across the adult lifespan. Here, we investigated self-reported sleep quality in relation to COVID stress and factors that may protect against experiencing poor sleep quality from high COVID stress, including social support and religiosity. Method: We recruited non-Hispanic Black (n = 73) and non-Hispanic White (n = 178) participants across the adult lifespan (18-76 years) using an online, cross-sectional design during the COVID-19 pandemic (March 2021-June 2021). We asked participants to report information regarding demographics (age, race/ethnicity, years of education), sleep (sleep quality, sleep habits), and positive (social support, religious activities) and negative (events of discrimination, depression, general stress, COVID stress) psychosocial factors. Results: Across age and racial groups, better sleep habits were associated with better sleep quality, and higher COVID stress was linked to poorer sleep quality. Black participants reported higher quality sleep than White participants (p = 0.006). They also endorsed greater private and internal religiosity (p's < 0.001). Across racial groups, moderation analyses revealed a protective effect of religiosity against poor sleep (p's < 0.006). Specifically, individuals with high religious activity and high COVID stress did not experience poor sleep quality, but individuals with low religious activity and high COVID stress demonstrated poor sleep quality. These results remained significant when controlling for general stress. Discussion: Protective factors, such as religiosity, may mitigate the negative associations between high COVID stress and poor sleep quality.

Cardio-Dance Exercise to Improve Cognition and Mood in Older African Americans: A Propensity-Matched Cohort Study.

The current study sought to determine the influence of initial sleep quality and body mass index on the cognitive and mood outcomes of a community-based cardio-dance exercise program. Thirty-two older African Americans who participated in a 5-month cardio-dance exercise program were propensity-matched to 32 no-contact controls. Participants completed neuropsychological tests of attention, executive function, and memory and a self-reported depression measure at baseline and post-test. Among exercise participants, we observed significant improvements in depression (baseline = 6.16 ± 5.54, post-test = 4.66 ± 4.89, ηp2=.12, p = .009) and attention (baseline = 40.53 ± 14.01, post-test = 36.63 ± 13.29, ηp2=.12, p = .009) relative to controls. Improvements in executive function and attention were most pronounced among exercise participants with poor sleep quality (baseline = 7.71 ± 1.25, post-test = 8.29 ± 2.06, ηp2=.41, p = .04) and with obesity (baseline = 38.05 ± 12.78, post-test = 35.67 ± 13.82, ηp2=.30, p = .001), respectively. This study provides novel evidence that exercise has the potential to improve depression in older African Americans. For those with poor sleep quality or obesity, exercise can also improve some cognitive outcomes.

A systematic review and meta-analysis of individual differences in naturalistic sleep quality and episodic memory performance in young and older adults.

Better sleep quality has been associated with better episodic memory performance in young adults. However, the strength of sleep-memory associations in aging has not been well characterized. It is also unknown whether factors such as sleep measurement method (e.g., polysomnography, actigraphy, self-report), sleep parameters (e.g., slow wave sleep, sleep duration), or memory task characteristics (e.g., verbal, pictorial) impact the strength of sleep-memory associations. Here, we assessed if the aforementioned factors modulate sleep-memory relationships. Across age groups, sleep-memory associations were similar for sleep measurement methods, however, associations were stronger for PSG than self-report. Age group moderated sleep-memory associations for certain sleep parameters. Specifically, young adults demonstrated stronger positive sleep-memory associations for slow wave sleep than the old, while older adults demonstrated stronger negative associations between greater wake after sleep onset and poorer memory performance than the young. Collectively, these data show that young and older adults maintain similar strength in sleep-memory relationships, but age impacts the specific sleep correlates that contribute to these relationships.

Age and Race-Related Differences in Sleep Discontinuity Linked to Associative Memory Performance and Its Neural Underpinnings.

There is a strong relationship between sleep and memory for the details of past events. In old age, both episodic memory performance and related neural activity decline. These changes occur in parallel to age-related decreases in sleep quality. Thus, poor sleep quality may be an explanatory factor for poor memory in older adulthood. Furthermore, Black adults tend to sleep more poorly than White adults, and this could be explained by differences in health and psychosocial factors (e.g., socioeconomic status, race-related stress). However, there have been no studies investigating the effect of race on sleep quality, episodic memory, and memory-related neural function. In the current pilot study, we recruited a diverse sample of older and younger adults and measured their habitual sleep using a wrist-worn accelerometer for 1 week. We recorded their electroencephalography (EEG) as they performed an episodic memory task to assess the impact of habitual sleep on memory-related neural oscillations. We found that more variable sleep quality was associated with worse memory performance, particularly for older adults. Additionally, Black participants demonstrated greater intraindividual sleep variance than White participants, and greater sleep variance was strongly linked to reduced memory-related neural activity in Black participants. Taken together, maintaining good sleep quality is especially important for memory performance in older adulthood, and greater sleep variation, that is evident in Black adults, may hamper memory-related neural function.