Associations of Late-Life Sleep Medication Use With Incident Dementia in the Atherosclerosis Risk in Communities Study

Association Between Hypnotics and Dementia: A Mini Narrative Review

OBJECTIVE

This narrative review aims to provide a comprehensive assessment of the existing literature on the relationship between hypnotics and dementia, considering both potential link and inconclusive or lack of association.

METHODS

Data from studies that investigate the association between hypnotic medications and dementia were reviewed. Studies included both cohort studies and systematic reviews, participants with various type of dementia and hypnotics including benzodiazepines (BZDs) and Z-drugs (ZDs).

RESULTS

The existing literatures presents conflicting evidence regarding the association between hypnotics, including BZDs and ZDs, and the risk of dementia. Some studies suggest a potential link between prolonged use of hypnotics and an increased risk of dementia. However, other studies indicate inconclusive or lacking evidence regarding this association. Factors such as study design, sample characteristics, and control of confounding variables contribute to the variability in findings.

CONCLUSION

The relationship between hypnotics and dementia remains complex and controversial. While some studies suggest a potential association, others find inconclusive or conflicting evidence. Future research should focus on addressing methodological limitations, considering classifying dementia subtypes, and try to adjust medication lag time.

Recent advances in understanding of sleep disorders and disturbances for dementia risk and prevention

PURPOSE OF REVIEW

To synthesise the recent work examining the relationship between sleep disturbances and dementia, emphasising studies involving individuals with mild cognitive impairment (MCI) or Alzheimer's disease (AD) and/or those investigating AD biomarkers. Additionally, we provide an update on recent interventions targeting sleep-related issues in older adults with MCI or AD.

RECENT FINDINGS

Various studies have examined obstructive sleep apnoea, sleep duration, and circadian alterations in relation to Alzheimer's pathology and dementia risk, with an emerging body of evidence suggesting that cardiovascular disease, hypertension, glymphatic function, and inflammation might serve as plausible pathophysiological mechanisms contributing to dementia during critical brain periods. Conversely, recent studies investigating insomnia have produced disparate results. Regarding intervention studies, the scarcity of prospective randomised control trials poses a challenge in establishing the benefits of addressing sleep disorders and disturbances.

SUMMARY

Recent work examining the pathophysiological links between sleep and dementia is strongest for obstructive sleep apnoea and sleep duration, while findings in insomnia studies exhibit inconsistency, possibly due to varied associations with dementia among different insomnia subtypes. It is apparent that more longitudinal studies examining the underlying pathophysiological mechanisms are necessary, alongside more rigorous clinical trials. Although some trials are underway in this field, there is still scarcity in trials examining interventions for circadian disturbances.

Impact of Sleep Disorders and Disturbed Sleep on Brain Health: A Scientific Statement From the American Heart Association

Accumulating evidence supports a link between sleep disorders, disturbed sleep, and adverse brain health, ranging from stroke to subclinical cerebrovascular disease to cognitive outcomes, including the development of Alzheimer disease and Alzheimer disease-related dementias. Sleep disorders such as sleep-disordered breathing (eg, obstructive sleep apnea), and other sleep disturbances, as well, some of which are also considered sleep disorders (eg, insomnia, sleep fragmentation, circadian rhythm disorders, and extreme sleep duration), have been associated with adverse brain health. Understanding the causal role of sleep disorders and disturbances in the development of adverse brain health is complicated by the common development of sleep disorders among individuals with neurodegenerative disease. In addition to the role of sleep disorders in stroke and cerebrovascular injury, mechanistic hypotheses linking sleep with brain health and biomarker data (blood-based, cerebrospinal fluid-based, and imaging) suggest direct links to Alzheimer disease-specific pathology. These potential mechanisms and the increasing understanding of the "glymphatic system," and the recognition of the importance of sleep in poststroke recovery, as well, support a biological basis for the indirect (through the worsening of vascular disease) and direct (through specific effects on neuropathology) connections between sleep disorders and brain health. Given promising evidence for the benefits of treatment and prevention, sleep disorders and disturbances represent potential targets for early treatment that may improve brain health more broadly. In this scientific statement, we discuss the evidence supporting an association between sleep disorders and disturbances and poor brain health ranging from stroke to dementia and opportunities for prevention and early treatment.

Sleep Disturbances and Dementia Risk in Older Adults: Findings From 10 Years of National U.S. Prospective Data

INTRODUCTION

Previous research has identified a link between sleep disturbances and cognitive impairment; however, no study has examined this relationship using a national United States sample. This study examines how multiple longitudinal measures of sleep disturbances (sleep-initiation insomnia, sleep-maintenance insomnia, sleep-medication usage) are associated with dementia risk.

METHODS

Ten annual waves (2011-2020) of prospective cohort data from a nationally representative U.S. sample of adults aged ≥65 years were analyzed from the National Health and Aging Trends Study. Sleep disturbances were converted into a longitudinal score and measured as sleep-initiation insomnia (trouble falling asleep in 30 minutes), sleep-maintenance insomnia (trouble falling asleep after waking up early), and sleep-medication usage (taking medication to help sleep). Cox regression models analyzed time to dementia diagnosis for a sample of 6,284 respondents.

RESULTS

In the unadjusted model, sleep-initiation insomnia was significantly associated with a 51% increased dementia risk (hazard ratio=1.51, 95% CI=1.19, 1.90). Adjusted for sociodemographics, sleep-medication usage was significantly associated with a 30% increased dementia risk (adjusted hazard ratio=1.30, 95% CI=1.08-1.56). Adjusted for sociodemographics and health, sleep-maintenance insomnia was significantly associated with a 40% decreased dementia risk (adjusted hazard ratio=0.60, 95% CI=0.46, 0.77).

CONCLUSIONS

These findings suggest that sleep-initiation insomnia and sleep-medication usage may elevate dementia risk. On the basis of the current evidence, sleep disturbances should be considered when assessing the risk profile for dementia. Future research is needed to examine other sleep disturbance measures and to explore the mechanisms for decreased dementia risk among older adults with sleep-maintenance insomnia.

Associations Between Objectively Measured Sleep and Cognition: Main Effects and Interactions With Race in Adults Aged ≥50 Years

BACKGROUND

This study examined associations of actigraphy-estimated sleep parameters with concurrent and future cognitive performance in adults aged ≥ 50 years and explored interactions with race.

METHODS

Participants were 435 cognitively normal adults in the Baltimore Longitudinal Study of Aging who completed wrist actigraphy at baseline (mean = 6.6 nights) and underwent longitudinal testing of memory, attention, executive function, language, and visuospatial ability. On average, participants with follow-up data were followed for 3.1 years. Primary predictors were baseline mean total sleep time, sleep onset latency, sleep efficiency (SE), and wake after sleep onset (WASO). Fully adjusted linear mixed-effects models included demographics, baseline health-related characteristics, smoking status, sleep medication use, APOE e4 carrier status, and interactions of each covariate with time.

RESULTS

In adjusted models, higher SE (per 10%; B = 0.11, p = .012) and lower WASO (per 30 minutes; B = -0.12, p = .007) were associated with better memory cross-sectionally. In contrast, higher SE was associated with greater visuospatial ability decline longitudinally (B = -0.02, p = .004). Greater WASO was associated with poorer visuospatial ability cross-sectionally (B = -0.09, p = .019) but slower declines in visuospatial abilities longitudinally (B = 0.02, p = .002). Several sleep-cognition cross-sectional and longitudinal associations were stronger in, or limited to, Black participants (compared to White participants).

CONCLUSIONS

This study suggests cross-sectional sleep-cognition associations differ across distinct objective sleep parameters and cognitive domains. This study also provides preliminary evidence for racial differences across some sleep-cognition relationships. Unexpected directions of associations between baseline sleep and cognitive performance over time may be attributable to the significant proportion of participants without follow-up data and require further investigation.