Increased Risk of Dementia Among Sleep-Related Movement Disorders: A Population-Based Longitudinal Study in Taiwan

Sleep characteristics and risk of Alzheimer's disease: a systematic review and meta-analysis of longitudinal studies

BACKGROUND

Alzheimer's disease (AD) is on the rise in our aging society, making it crucial to identify additional risk factors to mitigate its increasing incidence. This systematic review and meta-analysis aimed to provide updated evidence regarding the association between sleep and AD.

METHODS

We conducted a comprehensive search of MEDLINE, EMBASE, and Web of Science databases from inception to July 2023 to identify longitudinal studies. Adjusted relative risks were pooled for each sleep characteristic, and a dose-response analysis was performed specifically for sleep duration.

RESULTS

A total of 15,278 records were initially retrieved, and after screening, 35 records were ultimately included in the final analysis. The results showed that insomnia (RR, 1.43; 95%CI, 1.17-1.74), sleep-disordered breathing (RR, 1.22; 95%CI, 1.07-1.39), as well as other sleep problems, including sleep fragmentation and sleep-related movement disorders, were associated with a higher risk of developing AD, while daytime napping or excessive daytime sleepiness (RR, 1.18; 95%CI, 1.00-1.40) only exhibited a trend toward a higher risk of AD development. Furthermore, our analysis revealed a significant association between self-reported sleep problems (RR, 1.34; 95%CI, 1.26-1.42) and the incidence of AD, whereas this association was not observed with sleep problems detected by objective measurements (RR, 1.14; 95%CI, 0.99-1.31). Moreover, both quite short sleep duration (< 4 h) and long duration (> 8 h) were identified as potential risk factors for AD.

CONCLUSIONS

Our study found the association between various types of sleep problems and an increased risk of AD development. However, these findings should be further validated through additional objective device-based assessments. Additional investigation is required to establish a definitive causal connection between sleep problems and AD.

Sleep Disorders and Dementia Risk in Older Patients with Kidney Failure: A Retrospective Cohort Study

Key Points

Background

Community-dwelling older adults with sleep disorders are at higher risk of developing dementia. Greater than 50% of older patients with kidney failure experience sleep disorders, which may explain their high burden of dementia.

Methods

Among 216,158 patients (aged 66 years and older) with kidney failure (United States Renal Data System; 2008–2019), we estimated the risk of dementia (including subtypes) associated with sleep disorders using Cox proportional hazards models with propensity score weighting. We tested whether positive airway pressure (PAP) therapy was associated with reduced dementia risk among patients with obstructive sleep apnea (OSA).

Results

26.3% of patients were diagnosed with sleep disorders; these patients had a higher 5-year unadjusted cumulative incidence for any type of dementia (36.2% versus 32.3%; P < 0.001), vascular dementia (4.4% versus 3.7%; P < 0.001), and other/mixed dementia (29.3% versus 25.8%; P < 0.001). Higher risk of any type of dementia was identified in patients with insomnia (adjusted hazard ratio [aHR], 1.42; 95% confidence interval [CI], 1.34 to 1.51), sleep-related breathing disorders (SRBDs) (aHR, 1.20, 95% CI, 1.17 to 1.23), and other sleep disorders (aHR, 1.24; 95% CI, 1.11 to 1.39). Higher vascular dementia risk was observed in patients with insomnia (aHR, 1.43; 95% CI, 1.19 to 1.73) and SRBDs (aHR, 1.15; 95% CI, 1.07 to 1.24). Patients with SRBDs (aHR, 1.07; 95% CI, 1.00 to 1.15) were at higher risk of Alzheimer disease. Among patients with OSA, PAP therapy was associated with lower risk of any type of dementia (aHR, 0.82; 95% CI, 0.76 to 0.90) and vascular dementia (aHR, 0.65; 95% CI, 0.50 to 0.85).

Conclusions

Older patients with kidney failure and sleep disorders are at a higher risk of dementia. Sleep is an important modifiable factor that should be considered for targeted interventions to mitigate dementia risk in patients with kidney failure. For patients with OSA, PAP therapy is associated with lower dementia risk.

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.

The effect of sleep disorders on dementia risk in patients with traumatic brain injury: A large-scale cohort study

Introduction

We investigated the association between sleep disorders (SDs) and incident dementia in adults with traumatic brain injury (TBI).

Methods

Adults with a TBI between 2003 and 2013 were followed until incident dementia. Sleep disorders at TBI were predictors in Cox regression models, controlling for other dementia risks.

Results

Over 52 months, 4.6% of the 712,708 adults (59% male, median age 44, <1% with SD) developed dementia. An SD was associated with a 26% and a 23% of increased risk of dementia in male and female participants (hazard ratio [HR] 1.26, 95% confidence interval [CI] 1.11-1.42 and HR 1.23, 95% CI 1.09-1.40, respectively). In male participants, SD was associated with a 93% increased risk of early-onset dementia (HR 1.93, 95% CI 1.29-2.87); this did not hold in female participants (HR 1.38, 95% CI 0.78-2.44).

Discussion

In a province-wide cohort, SDs at TBI were independently associated with incident dementia. Clinical trials testing sex-specific SD care after TBI for dementia prevention are timely.

Highlights

TBI and sleep disorders are linked to each other, and to dementia.It is unclear if sleep disorders pose a sex-specific dementia risk in brain injury.In this study, presence of a sleep disorder increased dementia risk in both sexes.The risk differed by type of sleep disorder, which differed between the sexes.Sleep disorder awareness and care in persons with brain injury is vital for dementia prevention.

Circadian disruption and sleep disorders in neurodegeneration

Disruptions of circadian rhythms and sleep cycles are common among neurodegenerative diseases and can occur at multiple levels. Accumulating evidence reveals a bidirectional relationship between disruptions of circadian rhythms and sleep cycles and neurodegenerative diseases. Circadian disruption and sleep disorders aggravate neurodegeneration and neurodegenerative diseases can in turn disrupt circadian rhythms and sleep. Importantly, circadian disruption and various sleep disorders can increase the risk of neurodegenerative diseases. Thus, harnessing the circadian biology findings from preclinical and translational research in neurodegenerative diseases is of importance for reducing risk of neurodegeneration and improving symptoms and quality of life of individuals with neurodegenerative disorders via approaches that normalize circadian in the context of precision medicine. In this review, we discuss the implications of circadian disruption and sleep disorders in neurodegenerative diseases by summarizing evidence from both human and animal studies, focusing on the bidirectional links of sleep and circadian rhythms with prevalent forms of neurodegeneration. These findings provide valuable insights into the pathogenesis of neurodegenerative diseases and suggest a promising role of circadian-based interventions.

Periodic limb movements during sleep: a narrative review

Objective

Using narrative review techniques, this paper evaluates the evidence for separable underlying patho-mechanisms of periodic limb movements (PLMs) to separable PLM motor patterns and phenotypes, in order to elucidate potential new treatment modalities.

Background

Periodic limb movement disorder (PLMD) is estimated to occur in 5–8% of the paediatric population and 4–11% of the general adult population. Due to significant sleep fragmentation, PLMD can lead to functional impairment, including hyperactivity and delayed language development in children, and poor concentration and work performance in adults. Longitudinal data demonstrate that those with PLMD are at greater risk of depression and anxiety, and a 4-fold greater risk of developing dementia. PLMD has been extensively studied over the past two decades, and several key insights into the genetic, pathophysiological, and neural correlates have been proposed. Amongst these proposals is the concept of separable PLM phenotypes, proposed on the basis of nocturnal features such as the ratio of limb movements and distribution throughout the night. PLM phenotype and presentation, however, varies significantly depending on the scoring utilized and the nocturnal features examined, across age, and co-morbid clinical conditions. Furthermore, associations between these phenotypes with major neurologic and psychiatric disorders remain controversial.

Methods

In order to elucidate potential divergent biological pathways that may help clarify important new treatment modalities, this paper utilizes narrative review and evaluates the evidence linking PLM motor patterns and phenotypes with hypothesised underlying patho-mechanisms. Distinctive, underlying patho-mechanisms include: a pure motor mechanism originating in the spinal cord, iron deficiency, dopamine system dysfunction, thalamic glutamatergic hyperactivity, and a more cortical-subcortical interplay. In support of the latter hypothesis, PLM rhythmicity appears tightly linked to the microarchitecture of sleep, not dissimilarly to the apnoeic/hypopneic events seen in obstructive sleep apnea (OSA).

Conclusions

This review closes with a proposal for greater investigation into the identification of potential, divergent biological pathways. To do so would require prospective, multimodal imaging clinical studies which may delineate differential responses to treatment in restless legs syndrome (RLS) without PLMS and PLMS without RLS. This could pave the way toward important new treatment modalities.

Sleep disorders and risk of dementia in patients with new-onset type 2 diabetes: A nationwide population-based cohort study

BACKGROUND

This study examined the relationship between sleep disorders and the risk of dementia in patients with newly diagnosed type 2 diabetes.

METHODS

This study used the Korean Health Screening Cohort data and included 39 135 subjects aged ≥40 years with new-onset type 2 diabetes between 2004 and 2007, with follow-up throughout 2013. Sleep disorders were measured by F51(sleep disorders not due to a substance or known physiological condition) or G47(sleep disorders) under International Classification of Diseases, Tenth Revision (ICD-10) codes as a primary diagnosis, and the adjusted hazard ratio (AHR) and 95% CI of all-cause dementia, Alzheimer disease, vascular dementia, and other dementia were estimated using multivariable Cox proportional hazards regression models.

RESULTS

In the patients with type 2 diabetes with an age range between 42 and 84 years (M = 57.8, SD = 9.5), this study identified 2059 events of dementia during an average follow-up time of 5.7 years. In patients with type 2 diabetes, subjects with sleep disorders were associated with an increased risk of all-cause dementia (AHR, 1.46; 95% CI, 1.19-1.80), Alzheimer disease (AHR, 1.39; 95% CI, 1.02-1.88), and other dementia (AHR, 1.69; 95% CI, 1.23-2.31) compared to those without sleep disorders. Men (AHR, 1.93; 95% CI, 1.42-2.62) and older adults (AHR, 1.70; 95% CI, 1.35-2.15) with sleep disorders were associated with an increased risk of dementia than their counterparts without sleep disorders among patients with type 2 diabetes.

CONCLUSIONS

These findings suggest that sleep disorders are significantly associated with an increased risk of dementia in patients with new-onset type 2 diabetes.

Contributions of Modifiable Risk Factors to Dementia Incidence: A Bayesian Network Analysis

OBJECTIVE

To determine and compare the contributions of modifiable risk factors (RFs) with the prevention of dementia in older adults.

DESIGN

A systematic review and Bayesian network meta-analysis (NMA). The observational group was set as a reference to collect all existing RFs and compare them with each other.

SETTING AND PARTICIPANTS

An exhaustive and comprehensive literature search strategy was used to identify relevant prospective cohort studies from several online databases from their inception to May 1, 2019. Participants without dementia were adults aged greater than 50 years.

MEASURES

The required data were extracted from the eligible studies to facilitate the Bayesian NMA.

RESULTS

Forty-three cohort studies with 277,294 participants were included in this NMA. Using the observation group as the reference, all defined RFs, except for antioxidants, were associated with lower risks of all-cause dementia [no sleep disturbances (odds ratio, OR 0.43, 95% credible interval, CrI 0.24-0.62), a high level of education (OR 0.50, 95% CrI 0.34-0.66), no history of diabetes (OR 0.57, 95% CrI 0.36-0.78), nonobese patients (OR 0.61, 95% CrI 0.39-0.83), no smoking history (OR 0.62, 95% CrI 0.45-0.79), living with family members (OR 0.67, 95% CrI 0.45-0.89), participation in physical exercise (OR 0.73, 95% CrI 0.46-0.94), abstinence from drinking (OR 0.78, 95% CrI 0.56-0.99), and no history of hypertension (OR 0.80, 95% CrI 0.65-0.96)].

CONCLUSIONS/RELEVANCE

The findings provide reliable support for the hypothesis that modifiable somatic and lifestyle factors are strong predictors of all-cause dementia.

Impact of Sleep Disorder as a Risk Factor for Dementia in Men and Women

Sleep is an essential physiological process, especially for proper brain function through the formation of new pathways and processing information and cognition. Therefore, when sleep is insufficient, this can result in pathophysiologic conditions. Sleep deficiency is a risk factor for various conditions, including dementia, diabetes, and obesity. Recent studies have shown that there are differences in the prevalence of sleep disorders between genders. Insomnia, the most common type of sleep disorder, has been reported to have a higher incidence in females than in males. However, sex/gender differences in other sleep disorder subtypes are not thoroughly understood. Currently, increasing evidence suggests that gender issues should be considered important when prescribing medicine. Therefore, an investigation of the gender-dependent differences in sleep disorders is required. In this review, we first describe sex/gender differences not only in the prevalence of sleep disorders by category but in the efficacy of sleep medications. In addition, we summarize sex/gender differences in the impact of sleep disorders on incident dementia. This may help understand gender-dependent pathogenesis of sleep disorders and develop therapeutic strategies in men and women.

Risk of Dementia in Adults With ADHD: A Nationwide, Population-Based Cohort Study in Taiwan

OBJECTIVE

This study aimed to investigate the association between adults with ADHD and the risk of developing dementia.

METHOD

Utilizing National Health Insurance Research Database of Taiwan, ADHD patients were identified and compared with age- and gender-matched controls (1:3).

RESULTS

Of the study participants, 37 (5.48%) developed dementia compared with 81 (4.0%) in the control group. Cox proportional hazards regression analysis revealed that the study participants were more likely to develop dementia. The crude hazard ratio (HR) is 3.418 (95% confidence interval [CI] = [2.289, 5.106], p < .001), and adjusted HR is 4.008 (95% CI = [2.526, 6.361], p < .001) in risk of developing dementia after adjusted for age, gender, comorbidities, geographical area of residence, urbanization level of residence, and monthly income.

CONCLUSION

Adults with ADHD have a 3.4-fold risk of developing dementia, and other large or national data sets should be explored to support the current findings.

Neurologic Diseases and Sleep

Sleep disorders and neurologic illness are common and burdensome in their own right; when combined, they can have tremendous negative impact at an individual level as well as societally. The socioeconomic burden of sleep disorders and neurologic illness can be identified, but the real cost of these conditions lies far beyond the financial realm. There is an urgent need for comprehensive care and support systems to help with the burden of disease. Further research in improving patient outcomes in those who suffer with these conditions will help patients and their families, and society in general.