Interactive association between insomnia symptoms and sleep duration for the risk of dementia-a prospective study in the Swedish National March Cohort

Sleep disturbances and disorders in the memory clinic: Self-report, actigraphy, and polysomnography

BackgroundSleep disturbances are common in dementia but rarely studied in memory clinics.ObjectiveIn a memory clinic setting we aimed to (1) identify rates of obstructive sleep apnea (OSA), abnormal sleep duration, circadian phase shift, insomnia, poor sleep quality, and REM sleep behavior disorder (RBD); (2) assess concordance between self-reported and actigraphy-derived measures; investigate associations between sleep disturbances; and (3) neuropsychological performance and (4) cognitive status.MethodsAdults over 50 at a memory clinic between 2009-2024 were included. OSA was assessed via polysomnography and prior history. Sleep duration and circadian phase were measured by self-report and actigraphy. Self-report questionnaires evaluated insomnia, sleep quality, and RBD. Global cognition, processing speed, memory, and executive function were assessed. Analysis of Covariance and multinomial logistic regression examined the impact of OSA, sleep duration, insomnia, and sleep quality on cognition and cognitive status.Results1234 participants (Mage 67.2, 46%M) were included. 75.3% had OSA, while 12.7% were previously diagnosed. Insomnia affected 12.0%, 54.3% had poor sleep quality, and 14.2% endorsed RBD symptoms. Self-reported short (30.5%) and long (10.2%) sleep exceeded actigraphy rates (8.5% and 5.1%) with poor concordance between measures. OSA was linked to impaired global cognition and memory (p < 0.05). Prolonged sleep predicted deficits in global cognition, processing speed, memory, and executive function and a higher risk of aMCI (all p < 0.05). Poor sleep quality was linked to better memory (p < 0.05).ConclusionsDespite discrepancies between self-reported and objective prevalence rates, sleep disturbances are highly prevalent in memory clinics and impact cognition, necessitating further examination.

Impact of environmental and lifestyle factors on adolescent sleep health in urban and semiurban areas

OBJECTIVES

This study examines the impact of lifestyle factors on adolescent sleep health across urban and semiurban settings.

METHODS

A cross-sectional survey was conducted among 1459 adolescents aged 14-19years from Tabriz (urban) and Hadishahr (semiurban), two cities with contrasting environmental conditions. Sleep duration and sleep deprivation were assessed using self-reported data, alongside key sociodemographic, behavioral, and health-related factors.

RESULTS

The results showed that adolescents in urban area were significantly more likely to experience shorter sleep durations (OR=0.63, 95% CI [0.48, 0.83]) and sleep deprivation (OR=0.66, 95% CI [0.51, 0.85]) compared to those in semiurban environments. Age was positively associated with short sleep (OR=1.21, 95% CI [1.07, 1.38]), while smoking (OR=1.46, 95% CI [1.02, 2.08]) and chronic cough (OR=1.35, 95% CI [1.01, 1.80]) were also linked to reduced sleep duration. In contrast, semiurban residents slept an average of 20minutes longer than urban residents (β=0.34, 95% CI [0.17, 0.51]). Sleep deprivation was strongly associated with lower Parent's income (OR=0.78, 95% CI [0.61, 0.98]) and daytime fatigue (OR=1.58, 95% CI [1.26, 2.00]).

CONCLUSIONS

The study highlights the need for public health interventions that address environmental barriers to healthy sleep, particularly in urban settings, to mitigate the long-term health risks associated with sleep deprivation.

Insomnia and risk of all-cause dementia: A systematic review and meta-analysis

BACKGROUND

The evidence on the relationship between insomnia and risk of dementia, Alzheimer's disease (AD), and Vascular dementia (VD) is not consistent. We conducted this meta-analysis to examine the evidence for the risk of developing dementia, AD, or VD in patients with all subtypes of insomnia.

METHODS

A comprehensive search of PubMed, Embase, and the Cochrane Library was conducted using the following search strings: 'Insomnia OR Sleep initiation and Maintenance disorders OR Early morning awakening' AND 'Dementia OR Alzheimer's Disease OR Vascular Dementia' AND 'Risk'. Data extraction was done independently by two researchers. Pooled odds ratio (OR) accompanied by 95% confidence interval (CI) were calculated using either a random-effects model or a fixed-effects model. Sensitivity analyses were performed to assess the robustness of the findings. The potential for publication bias was evaluated through Egger's test and Begg's test.

RESULTS

This meta-analysis included 16 studies with a combined sample size of over 9 million individuals. Pooled analyses revealed a significant association between insomnia and dementia risk (OR = 1.36; 95% CI: 1.01-1.84), with increased risks for AD (OR = 1.52; 95% CI: 1.19-1.93) and VD (OR = 2.10; 95% CI = 2.06-2.14). Subgroup analyses showed no evidence of associations between initial insomnia (OR = 1.01; 95% CI = 0.71-1.31), sleep-maintenance insomnia (OR = 0.88; 95% CI = 0.66-1.17), and early morning awakening (OR = 0.94; 95% CI = 0.83-1.07) with dementia risk. Insomnia patients from Europe (OR = 1.24; 95% CI = 1.14-1.35), Asia (OR = 2.19; 95% CI = 2.06-2.32), and the Americas (OR = 1.05; 95% CI =  1.04-1.07) had varying risks of dementia. Subgroups with less than five years of follow-up (OR = 2.16; 95% CI = 1.81-2.60) exhibited higher dementia risks in insomnia patients, while those with more than five years of follow-up (OR = 1.17; 95% CI = 1.03-1.33) showed a lower risk.

CONCLUSION

Our meta-analysis reveals that insomnia is linked to the risk of dementia, AD, and VD. These findings suggest that insomnia may significantly contribute to the risk of all-cause dementia, highlighting the importance of early intervention and management of insomnia. Despite our efforts to minimize and explore the sources of heterogeneity, it still remained, and therefore our results should be interpreted with caution.

Dose-response associations of device-measured sleep regularity and duration with incident dementia in 82391 UK adults

BACKGROUND

Sleep is a crucial lifestyle factor with impacts on mental and cognitive health. The associations between objectively measured sleep and risk of incident dementia are not yet fully understood. To evaluate the associations of device-measured sleep duration and regularity with incident dementia and explore whether sleep regularity moderates the association of sleep duration with dementia.

METHODS

Population-based prospective cohort study of 82,391 adults aged 43 to 79 years from the UK Biobank accelerometry subsample, collected between 2013 and 2015, followed up to 2022. Device-based sleep duration (h/day) and sleep regularity index (SRI), a metric ranging from 0-100 that quantifies a person's sleep regularity (with a greater value indicating higher consistency), were calculated from wrist-worn accelerometry data recorded over the course of one week. Incident all-cause dementia cases were obtained from national hospital admission, primary care and mortality data followed up to 30 November 2022. We used Cox proportional hazard models to estimate the hazard ratios (HRs) for incident dementia after adjustment for common demographic and clinical covariates.

RESULTS

Over a mean follow-up of 7.9 years, 694 incident dementia cases occurred. We observed a U-shaped association between sleep duration and incident dementia, with only short sleep (< 7 h) being significantly associated with a higher risk of dementia. The median sleep duration for short sleepers (< 7 h) of 6.5 h, compared to the reference point of 7.9 h was associated with HR of 1.19 (95%CI 1.01,1.40) for incident dementia. Sleep regularity was negatively associated with dementia risk in a near-linear fashion (linear p = 0.01, non-linear p = 0.57). When we dichotomized sleep regularity, those in the higher sleep regularity group (SRI ≥ 70) had an HR of 0.74 (95%CI 0.63, 0.87) compared to those with lower sleep regularity (SRI < 70). The beneficial associations between sleep regularity and incident dementia were present only among participants with short (< 7 h) and long (≥ 8 h) sleep duration.

CONCLUSIONS

Assuming that the associations we observed are causal, maintaining a regular sleep pattern may help offset the deleterious association of inadequate sleep duration with dementia. Interventions aimed at improving sleep regularity may be a viable option for people not able to achieve the recommended hours of sleep.

Mindfulness Meditation for Sleep Disturbances Among Individuals with Cognitive Impairment: A Scoping Review

Background: This scoping review investigates the effectiveness of mindfulness meditation in alleviating sleep disturbances among individuals with mild cognitive impairment (MCI) and Alzheimer's disease (AD). With the rising prevalence of dementia and its profound impact on cognitive function and quality of life, this review aims to synthesize existing research and identify gaps in the literature. Methods: We systematically searched six electronic databases (CINAHL, Embase, Medline, PsycINFO, PubMed, and Scopus) from 2004 to 2024, yielding 462 potentially relevant articles. Screening was conducted using ASReview, an AI ranking tool, which facilitated the selection of studies. Ultimately, seven studies that met our stringent eligibility criteria were included in the review. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines for reporting. Results: Our findings indicate that mindfulness meditation significantly improves sleep quality, reduces insomnia severity, and enhances overall well-being in this at-risk population. Notably, interventions that combine structured, face-to-face sessions with at-home practice emerged as the most effective. Conclusions: Despite these positive outcomes, methodological limitations, including small sample sizes and reliance on self-reported measures, underscore the need for more rigorous long-term studies. This review highlights the potential of mindfulness meditation as a low-cost, scalable intervention to improve sleep and cognitive health in older adults, paving the way for future research and clinical applications.

Association between sleep and gallstone disease in United States adults: A cross-sectional study

BACKGROUND

Both gallstone disease and sleep disorders are important public health problems. Few studies to date have investigated the associations between sleep and gallstone disease in humans. This study aimed to assess whether sleep factors (sleep time, sleep amounts, trouble sleeping) were associated with gallstone disease in the United States adults.

METHODS

This was a population-based cross-sectional study of US adults, which included data of participants aged over 20 years from the National Health and Nutrition Examination Survey (NHANES) gathered between 2017 and March 2020. The assessment of gallstone disease and sleep factors was based on self-reported data. We used sample-weighted logistic regression and restricted cubic spline models to explore the associations between sleep factors and gallstone disease. Subgroup analyses were conducted to assess the interaction between trouble sleeping and interacting factors.

RESULTS

The prevalence of gallstone disease was 11% among the 9,210 adult participants. Going to bed late on weekdays (OR, 1.41; 95% CI, 1.15 to 1.74) and weekends (OR, 1.43; 95% CI, 1.14 to 1.78), and short sleep duration on weekdays (OR, 1.29; 95% CI, 1.00 to 1.68) were factors associated with increased risk of gallstone disease, and we detected dose-response associations with the restricted cubic spline model (RCS) models, after adjusting for confounders. Presenting trouble sleeping was associated with increased risk of gallstone disease (OR, 1.52; 95% CI, 1.03 to 2.23) and the association was influenced by the presence of thyroid disease (P for interaction = 0.037).

CONCLUSIONS

Our study results indicate that going to bed late, short sleep duration, and trouble sleeping were associated with increased risk of gallstone disease in a nationally representative sample of adults in the US.

Association between coffee and tea consumption and the risk of dementia in individuals with hypertension: a prospective cohort study

Many studies have shown that drinking coffee and tea may be associated with the risk of hypertension and dementia. Limited research exists on their impact on dementia risk in hypertensive patients. This study aimed to determine the association between coffee and tea consumption and the risk of dementia development in hypertensive population by utilizing Cox proportional risk modeling with 453,913 participants from a UK biobank. Our findings reveal a J-shaped and U-shaped association between the risk of all-cause dementia and the consumption of coffee and tea respectively in hypertensive people. The hypertensive patients who drink 0.5-1 cup of coffee or 4-5 cups of tea per day have the lowest risk of dementia. A U-shaped relationship was observed between daily caffeine consumption and the risk of developing all-cause dementia and vascular dementia in the hypertensive population. Furthermore, the significant association between the amount of coffee and tea consumed and the risk of all-cause and vascular dementia were more likely to be found in hypertensive patients than in the non-hypertensive population.

Contribution of CNS and extra-CNS infections to neurodegeneration: a narrative review

Central nervous system infections have been suggested as a possible cause for neurodegenerative diseases, particularly sporadic cases. They trigger neuroinflammation which is considered integrally involved in neurodegenerative processes. In this review, we will look at data linking a variety of viral, bacterial, fungal, and protozoan infections to Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis and unspecified dementia. This narrative review aims to bring together a broad range of data currently supporting the involvement of central nervous system infections in the development of neurodegenerative diseases. The idea that no single pathogen or pathogen group is responsible for neurodegenerative diseases will be discussed. Instead, we suggest that a wide range of susceptibility factors may make individuals differentially vulnerable to different infectious pathogens and subsequent pathologies.

Sleep patterns, genetic predisposition, and risk of chronic liver disease: A prospective study of 408,560 UK Biobank participants

BACKGROUND

Little is known about the role that combined sleep behaviors play in the association with chronic liver disease (CLD) risk.

METHODS

We included 408,560 participants initially free of CLD from the UK Biobank. A healthy sleep pattern was defined by early chronotype, sleep duration of 7-8 h/day, no insomnia, no snoring, and no excessive daytime sleepiness. Cox regression models were used to examine the association of healthy sleep pattern with incident CLD and their interaction with PNPLA3 genetic risk.

RESULTS

During a median 12.5 years of follow-up, we documented 10,915 incident all-cause CLD cases, including 388 viral hepatitis, 4782 non-alcoholic fatty liver disease (NAFLD), 1356 cirrhosis, 973 alcoholic liver disease, and 725 liver cancer cases. Compared to participants with a healthy sleep score of 0-1, the hazard ratio (HR) (95 % confidence interval [CI]) for those with a sleep score of 5 was 0.54 (0.49, 0.60) for CLD, 0.52 (0.30, 0.90) for viral hepatitis, 0.47 (0.41, 0.55) for NAFLD, 0.57 (0.43, 0.75) for cirrhosis, 0.32 (0.23, 0.44) for alcoholic liver disease, and 0.53 (0.37, 0.77) for liver cancer. Healthy sleep pattern and PNPLA3 genetic risk exerted significant additive effects on CLD risk (relative excess risk due to the interaction: 0.05; attributable proportion due to the interaction: 13 %).

LIMITATIONS

Measurement error was unavoidable for self-reported data on sleep behaviors.

CONCLUSIONS

Our analyses provide evidence that healthy sleep pattern was inversely associated with the development of CLD, and participants with higher genetic risk were more likely to develop CLD when exposed to the unhealthy sleep pattern.

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.