The brain structure and genetic mechanisms underlying the nonlinear association between sleep duration, cognition and mental health

Lacticaseibacillus rhamnosus GG alleviates sleep deprivation-induced intestinal barrier dysfunction and neuroinflammation in mice

Consuming probiotic products is a solution that people are willing to choose to augment health. As a global health hazard, sleep deprivation (SD) can cause both physical and mental diseases. The present study investigated the protective effects of Lacticaseibacillus rhamnosus GG (LGG), a widely used probiotic, on a SD mouse model. Here, it has been shown that SD induced intestinal damage in mice, while LGG supplementation attenuated disruption of the intestinal barrier and enhanced the antioxidant capacity. Microbiome analysis revealed that SD caused dysbiosis in the gut microbiota, characterized by increased levels of Clostridium XlVa, Alistipes, and Desulfovibrio, as well as decreased levels of Ruminococcus, which were partially ameliorated by LGG. Moreover, SD resulted in elevated pro-inflammatory cytokine concentrations in both the intestine and the brain, while LGG provided protection in both organs. LGG supplementation significantly improved locomotor activity in SD mice. Although heat-killed LGG showed some protective effects in SD mice, its overall efficacy was inferior to that of live LGG. In terms of mechanism, it was found that AG1478, an inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase, could diminish the protective effects of LGG. In conclusion, LGG demonstrated the ability to alleviate SD-induced intestinal barrier dysfunction through EGFR activation and alleviate neuroinflammation.

Acute 2-phenyl-3-(phenylselanyl)benzofuran treatment reverses the neurobehavioral alterations induced by sleep deprivation in mice

Sleep is a fundamental state for maintaining the organism homeostasis. Disruptions in sleep patterns predispose to the appearance of memory impairments and mental disorders, including depression. Recent pre-clinical studies have highlighted the antidepressant-like properties of the synthetic compound 2-phenyl-3-(phenylselanyl)benzofuran (SeBZF1). To further investigate the neuromodulatory effects of SeBZF1, this study aimed to assess its therapeutic efficacy in ameliorating neurobehavioral impairments induced by sleep deprivation (SD) in mice. For this purpose, a method known as multiple platforms over water was used to induce rapid eye movement (REM) SD. Two hours after acute SD (24 h), male Swiss mice received a single treatment of SeBZF1 (5 mg/kg, intragastric route) or fluoxetine (a positive control, 20 mg/kg, intraperitoneal route). Subsequently, behavioral tests were conducted to assess spontaneous motor function (open-field test), depressive-like behavior (tail suspension test), and memory deficits (Y-maze test). Brain structures were utilized to evaluate oxidative stress markers, monoamine oxidase (MAO) and acetylcholinesterase (AChE) activities. Our findings revealed that SD animals displayed depressive-like behavior and memory impairments, which were reverted by SeBZF1 and fluoxetine treatments. SeBZF1 also reverted the increase in lipoperoxidation levels and glutathione peroxidase activity in the pre-frontal cortex in mice exposed to SD. Besides, the increase in hippocampal AChE activity induced by SD was overturned by SeBZF1. Lastly, cortical MAO-B activity was reestablished by SeBZF1 in mice that underwent SD. Based on the main findings of this study, it can be inferred that the compound SeBZF1 reverses the neurobehavioral alterations induced by sleep deprivation in male Swiss mice.

Mendelian randomization identifies causal effects of major depressive disorder on accelerated aging

BACKGROUND

Evidence links major depressive disorder (MDD) with aging, but it's unclear if MDD accelerates aging and what factors mediate this transition.

METHODS

Two-sample Mendelian randomization (MR) analyses were applied to estimate the causal association between MDD and frailty index (FI), telomere length (TL), and appendicular lean mass (ALM) from available genome-wide association studies in populations of European ancestry. Furthermore, we conducted mediation MR analyses to assess the mediating effects of 31 lifestyle factors or diseases on the causal relationship between MDD and aging.

RESULTS

MDD was significantly causally associated with increased FI (βIVW = 0.23, 95 % CI = 0.18 to 0.28, p = 1.20 × 10-17), shorter TL (βIVW = -0.04, 95 % CI = -0.07 to -0.01, p = 0.01), and decreased ALM (βIVW = -0.07, 95 % CI = -0.11 to -0.03, p = 3.54 × 10-4). The mediation analysis through two-step MR revealed smoking initiation (9.09 %), hypertension (6.67 %) and heart failure (5.36 %) mediated the causal effect of MDD on FI. Additionally, alcohol use disorders and alcohol dependence on the causal relationship between MDD and TL were found to be 17.52 % and 17.13 % respectively.

LIMITATIONS

Confounding, statistical power, and Euro-centric focus limit generalization.

CONCLUSION

Overall, individuals with MDD may be at a higher risk of experiencing premature aging, and this risk is partially influenced by the pathways involving smoking, alcohol use, and cardiovascular health. It underscores the importance of early intervention and comprehensive health management in individuals with MDD to promote healthy aging and overall well-being.

Sleep patterns and risk of chronic disease as measured by long-term monitoring with commercial wearable devices in the All of Us Research Program

Poor sleep health is associated with increased all-cause mortality and incidence of many chronic conditions. Previous studies have relied on cross-sectional and self-reported survey data or polysomnograms, which have limitations with respect to data granularity, sample size and longitudinal information. Here, using objectively measured, longitudinal sleep data from commercial wearable devices linked to electronic health record data from the All of Us Research Program, we show that sleep patterns, including sleep stages, duration and regularity, are associated with chronic disease incidence. Of the 6,785 participants included in this study, 71% were female, 84% self-identified as white and 71% had a college degree; the median age was 50.2 years (interquartile range = 35.7, 61.5) and the median sleep monitoring period was 4.5 years (2.5, 6.5). We found that rapid eye movement sleep and deep sleep were inversely associated with the odds of incident atrial fibrillation and that increased sleep irregularity was associated with increased odds of incident obesity, hyperlipidemia, hypertension, major depressive disorder and generalized anxiety disorder. Moreover, J-shaped associations were observed between average daily sleep duration and hypertension, major depressive disorder and generalized anxiety disorder. These findings show that sleep stages, duration and regularity are all important factors associated with chronic disease development and may inform evidence-based recommendations on healthy sleeping habits.

Latent profile analysis of depression and its influencing factors in older adults raising grandchildren in China

OBJECTIVE

To explore the latent profile of depression in older adults raising grandchildren in China, and to analyze the differences in the characteristics of the different profiles of the population and the factors influencing them.

METHODS

This study utilized the 2018 China Health and Retirement Longitudinal Study (CHARLS). Through a cross-sectional study, the latent profile analysis was used to analyze the potential classification of depression among older adults raising grandchildren, and using ordered multi-categorical logistic regression analyses to assess the effects of each factor on their different classifications.

RESULTS

The 1271 older adults raising grandchildren with depression symptoms were divided into three categories: low-level depression (55.4%), moderate-level depression (31.2%), and high-level depression (13.4%). Ordered multi-categorical Logistic results showed: Gender, marital status, pension insurance, physical health status, life satisfaction, and IADL were predictors of latent profile classification of depression symptoms in older adults raising grandchildren (P < 0.05).

CONCLUSIONS

In the future of primary care, it will be more meaningful to provide targeted interventions for different subgroups of depression in older adults raising grandchildren.

Nonlinear relationships between sleep duration, mental health, and quality of life: The dangers of less sleep versus more sleep

BACKGROUND

Recent research has found a non-linear relationship between sleep duration and mental health/quality of life. However, it is currently unclear which age group is more affected by sleep duration and what the optimal sleep duration is for each age group. Additionally, the underlying mechanisms of the non-linear relationship between sleep duration and quality of life are not well understood.

METHODS

Therefore, this study utilized questionnaire data from 20,962 participants in the Chinese PBICR-2022 database(Cross-sectional study) and constructed models to analyze the relationship between sleep duration and quality of life.

RESULTS

The results showed that the optimal sleep duration varied among different age groups: approximately 9 h for adolescents, 8 h for early/middle-aged adults, and 7 h for older adults. Compared to other age groups, less or more sleep duration had a greater impact on mental health and quality of life in adolescents. Furthermore, mental health was found to play a significant mediating role between sleep duration and quality of life in both the less sleep group and the more sleep group, but this mediating effect was not significant among the older adults in the less sleep group, whereas the mediating effect of mental health was not significant among the middle-aged adults in the more sleep group.

CONCLUSIONS

This suggests that different age groups have different optimal sleep duration, and age may be an important factor influencing the relationship between sleep duration and mental health/quality of life, with mental health playing a mediating role in the relationship between sleep duration and quality of life.

Association of past and current sleep duration with structural brain differences: A large population-based study from the UK Biobank

OBJECTIVE

This study aimed to examine the association between past/current sleep duration and macro-/micro-structural brain outcomes and explore whether hypertension or social activity plays a role in such association.

METHODS

Within the UK Biobank, 40 436 dementia-free participants (age 40-70 years) underwent a baseline assessment followed by a brain magnetic resonance imaging (MRI) scan 9 years later. Past (baseline) and current (MRI scans) sleep duration (hours/day) were recorded and classified as short (≤5), intermediate (6-8), and long (≥9). Brain structural volumes and diffusion markers were assessed by MRI scans.

RESULTS

Compared with past intermediate sleep, past short sleep was related to smaller cortex volumes (standardized β [95 % CI]: -0.04 [-0.07, -0.02]) and lower regional fractional anisotropy (FA) (-0.08 [-0.13, -0.03]), while past long sleep was related to smaller regional subcortical volumes (standardized β: -0.04 to -0.07 for thalamus, accumbens, and hippocampus). Compared to current intermediate sleep, current short sleep was associated with smaller cortex volumes (-0.03 [-0.05, -0.01]), greater white matter hyperintensities (WMH) volumes (0.04 [0.01, 0.08]), and lower regional FA (-0.07 [-0.11, -0.02]). However, current long sleep was related to smaller total brain (-0.03 [-0.05, -0.02]), grey matter (-0.05 [-0.07, -0.03]), cortex (-0.05 [-0.07, -0.03]), regional subcortical volumes [standardized β: -0.05 to -0.09 for putamen, thalamus, hippocampus, and accumbens]), greater WMH volumes (0.06 [0.03, 0.09]), as well as lower regional FA (-0.05 [-0.09, -0.02]). The association between current long sleep duration and poor brain health was stronger among people with hypertension or low frequency of social activity (all Pinteraction <0.05).

CONCLUSIONS

Both past and current short/long sleep are associated with smaller brain volume and poorer white matter health in the brain, especially in individuals with hypertension and low frequency of social activity. Our findings highlight the need to maintain 6-8 h' sleep duration for healthy brain aging.

Ckip-1 3'UTR alleviates prolonged sleep deprivation induced cardiac dysfunction by activating CaMKK2/AMPK/cTNI pathway

Sleep deprivation (SD) has emerged as a critical concern impacting human health, leading to significant damage to the cardiovascular system. However, the underlying mechanisms are still unclear, and the development of targeted drugs is lagging. Here, we used mice to explore the effects of prolonged SD on cardiac structure and function. Echocardiography analysis revealed that cardiac function was significantly decreased in mice after five weeks of SD. Real-time quantitative PCR (RT-q-PCR) and Masson staining analysis showed that cardiac remodeling marker gene Anp (atrial natriuretic peptide) and fibrosis were increased, Elisa assay of serum showed that the levels of creatine kinase (CK), creatine kinase-MB (CK-MB), ANP, brain natriuretic peptide (BNP) and cardiac troponin T (cTn-T) were increased after SD, suggesting that cardiac remodeling and injury occurred. Transcript sequencing analysis indicated that genes involved in the regulation of calcium signaling pathway, dilated cardiomyopathy, and cardiac muscle contraction were changed after SD. Accordingly, Western blotting analysis demonstrated that the cardiac-contraction associated CaMKK2/AMPK/cTNI pathway was inhibited. Since our preliminary research has confirmed the vital role of Casein Kinase-2 -Interacting Protein-1 (CKIP-1, also known as PLEKHO1) in cardiac remodeling regulation. Here, we found the levels of the 3' untranslated region of Ckip-1 (Ckip-1 3'UTR) decreased, while the coding sequence of Ckip-1 (Ckip-1 CDS) remained unchanged after SD. Significantly, adenovirus-mediated overexpression of Ckip-1 3'UTR alleviated SD-induced cardiac dysfunction and remodeling by activating CaMKK2/AMPK/cTNI pathway, which proposed the therapeutic potential of Ckip-1 3'UTR in treating SD-induced heart disease.

The brain structure, inflammatory, and genetic mechanisms mediate the association between physical frailty and depression

Cross-sectional studies have demonstrated strong associations between physical frailty and depression. However, the evidence from prospective studies is limited. Here, we analyze data of 352,277 participants from UK Biobank with 12.25-year follow-up. Compared with non-frail individuals, pre-frail and frail individuals have increased risk for incident depression independent of many putative confounds. Altogether, pre-frail and frail individuals account for 20.58% and 13.16% of depression cases by population attributable fraction analyses. Higher risks are observed in males and individuals younger than 65 years than their counterparts. Mendelian randomization analyses support a potential causal effect of frailty on depression. Associations are also observed between inflammatory markers, brain volumes, and incident depression. Moreover, these regional brain volumes and three inflammatory markers-C-reactive protein, neutrophils, and leukocytes-significantly mediate associations between frailty and depression. Given the scarcity of curative treatment for depression and the high disease burden, identifying potential modifiable risk factors of depression, such as frailty, is needed.

Influence of physical exercise on negative emotions in college students: chain mediating role of sleep quality and self-rated health

Background

Negative emotions in college students are a significant factor affecting mental health, with suicide behaviors caused by negative emotions showing an annual increasing trend. Existing studies suggest that physical exercise is essential to alleviate negative feelings, yet the intrinsic mechanisms by which it affects negative emotions have not been fully revealed.

Objective

Negative emotions in college students represent a significant issue affecting mental health. This study investigates the relationship between physical exercise and negative emotions among college students, incorporating sleep quality and self-rated health (SRH) as mediators to analyze the pathway mechanism of how physical exercise affects students' negative emotions.

Methods

A cross-sectional study design was utilized, employing online questionnaires for investigation. The scales included the Physical Activity Rating Scale-3 (PARS-3), the Depression Anxiety Stress Scales-21 (DASS-21), the Pittsburgh Sleep Quality Index (PSQI), and the 12-Item Short Form Health Survey (SF-12), resulting in the collection of 30,475 valid questionnaires, with a validity rate of 91%. Chain mediation tests and Bootstrap methods were applied for effect analysis.

Results

The proportions of university students engaged in low, medium, and high levels of physical exercise were 77.6, 13.1, and 9.3%, respectively. The proportions of students experiencing "very severe" levels of stress, anxiety, and depression were 4.5, 10.9, and 3.6%, respectively. Physical exercise was significantly positively correlated with self-rated health (r = 0.194, p < 0.01), significantly negatively correlated with sleep quality (r = -0.035, p < 0.01), and significantly negatively correlated with stress, anxiety, and depression (r = -0.03, p < 0.01; r = -0.058, p < 0.01; r = -0.055, p < 0.01). Sleep quality was significantly negatively correlated with self-rated health (r = -0.242, p < 0.01). Mediation effect testing indicated that sleep quality and self-rated health partially mediated the relationship between physical exercise and negative emotions, with total effect, total direct effect, and total indirect effect values of -1.702, -0.426, and - 1.277, respectively.

Conclusion

College students primarily engage in low-intensity physical activity. Sleep quality and self-rated health mediate the impact of physical exercise on students' negative emotions. A certain level of physical activity can directly affect students' emotional states and indirectly influence their negative emotions via sleep and self-rated health. Regular engagement in physical activities primarily positively impacts emotional states by enhancing mood stability and overall emotional resilience.

Associations between sleep problems and cardiometabolic risk in maintenance hemodialysis patients: A multicenter study

The incidence of cardiovascular disease is increasing around the world, and it is one of the main causes of death in chronic kidney diseases patients. It is urgent to early identify the factors of cardiometabolic risk. Sleep problems have been recognized as a risk factor for cardiometabolic risk in both healthy people and chronic patients. However, the relationship between sleep problems and cardiometabolic risk has not been clearly explored in hemodialysis patients. This study aimed to investigate the relationship between sleep problems and cardiometabolic risk in 3025 hemodialysis patients by a multicenter study. After adjusting for confounders, binary logistic regression models showed that hemodialysis patients reported sleep duration greater than 7 h were more likely to be with hypertension, hyperglycemia, hypertriglyceridemia, and hypercholesterolemia. Patients reported sleep duration less than 7 h were more likely to be with hypertriglyceridemia and hypercholesterolemia, but the risks of hyperglycemia and Low HDL-cholesterol were decreased. Poor sleep quality was negatively correlated to low HDL cholesterol and hypertriglyceridemia. Moreover, gender-based differences were explained.

The Impact of Social Media Use on Sleep and Mental Health in Youth: a Scoping Review

PURPOSE OF REVIEW

Social media use (SMU) and other internet-based technologies are ubiquitous in today's interconnected society, with young people being among the commonest users. Previous literature tends to support that SMU is associated with poor sleep and mental health issues in youth, despite some conflicting findings. In this scoping review, we summarized relevant studies published within the past 3 years, highlighted the impacts of SMU on sleep and mental health in youth, while also examined the possible underlying mechanisms involved. Future direction and intervention on rational use of SMU was discussed.

RECENT FINDINGS

Both cross-sectional and longitudinal cohort studies demonstrated the negative impacts of SMU on sleep and mental health, with preliminary evidence indicating potential benefits especially during the COVID period at which social restriction was common. However, the limited longitudinal research has hindered the establishment of directionality and causality in the association among SMU, sleep, and mental health. Recent studies have made advances with a more comprehensive understanding of the impact of SMU on sleep and mental health in youth, which is of public health importance and will contribute to improving sleep and mental health outcomes while promoting rational and beneficial SMU. Future research should include the implementation of cohort studies with representative samples to investigate the directionality and causality of the complex relationships among SMU, sleep, and mental health; the use of validated questionnaires and objective measurements; and the design of randomized controlled interventional trials to reduce overall and problematic SMU that will ultimately enhance sleep and mental health outcomes in youth.

Association of sleep duration and risk of mental disorder: a systematic review and meta-analysis

BACKGROUND

The effects of sleep duration on the development of mental illness remain controversial. Therefore, it is necessary to identify the effects of long or short sleep duration on psychological disorders, which could reveal new ways for preventing and treating mental health conditions cheaply.

METHODS

Identifying published papers was accomplished by using the following five English databases on March 16, 2022: PubMed, MEDLINE, Embase, Web of Science databases, and Scopus. Cross-sectional and cohort studies were considered if they evaluated the association of sleep duration with all kinds of mental illness in adults. We excluded case reports, editorials, narrative reviews, and studies without detailed information on sleep duration. Summary effect-size estimates were expressed as risk ratios (RRs) or odds ratios (ORs) with 95% confidence intervals and were evaluated using random-effect models. Mantel-Haenszel's random-effects model was used to estimate the inconsistency index (I2) and Tau2 index (measurement of heterogeneity).

RESULTS

A total of 52 studies were included in this analysis, consisting of 14 cohort studies and 38 cross-sectional studies. These studies involved a combined sample size of 1,407,891 participants who met the inclusion criteria. Cohort (adjusted RR = 1.42, 95% CI: 1.26-1.60, P < .001, I2 = 37.6%, Tau2 = 0.014) and cross-sectional studies (adjusted OR = 1.67, 95% CI: 1.57-1.77, P < .001, I2 = 79.7%, Tau2 = 0.060) concluded that short sleep duration increased mental disorder risks. The same conclusions were acquired in the subgroup analysis, especially for depression (adjusted RR = 1.43, 95% CI: 1.24-1.65, P < .001, I2 = 80.4%, Tau2 = 0.082), anxiety (adjusted RR = 1.30, 95% CI: 1.04-1.63, P = .002, I2 = 0.0%, Tau2 = 0.000), and PTSD (adjusted RR = 1.35, 95% CI: 1.04-1.76, P = .022, I2 = 24.1%, Tau2 = 0.013) in cohort studies. The results of subgroup analysis indicated that long sleep duration was not a risk factor for depression (adjusted RR = 1.15, 95% CI: 0.98-1.34, P = .088, I2 = 63.4%, Tau2 = 0.045) and anxiety (adjusted RR = 1.37, 95% CI: 0.93-2.03, P = .114, I2 = 0.0%, Tau2 = 0.000).

CONCLUSIONS

Short sleep duration, not long sleep duration, is an independent predictor of developing mental disorders, particularly anxiety and depression.

Sleep duration and mental health in young adults

BACKGROUND

The association between sleep duration and mental illness has been established in middle-aged and older populations, yet remains less explored in younger adults. Additionally, a common limitation to existing studies is the lack of statistical power to explore less common disorders. The purpose of this study was to examine sleep duration as a predictor for a range of mental disorders and well-being in a longitudinal sample of young adults.

METHODS

Data were derived from two waves (w1, w2) of the SHoT survey, which invited all full-time university and college students in Norway. The response rates were 34.4 % (n = 62,498) in 2021 (w1) and 35.1 % (n = 59,554) 2022 (w2). This study utilized a nested longitudinal sample from both w1 and w2, encompassing 21,289 students. Demographics, sleep duration (w1), and mental health (w2) were measured by self-report questionnaires. Sex-stratified linear regression models and log-link binomial regression analyses were employed to determine the proportion and calculate the risk ratios, respectively, for mental illness across different sleep duration categories.

RESULTS

The mean age of the sample was 24.8 years ± 4.5 years (w1). Students with shorter sleep durations, and to some degree longer sleep durations (illustrating a ᒐ-shaped association), exhibited a higher risk for all assessed mental disorders and well-being outcomes one year later, compared to students sleeping 8-9 h. The ᒐ-shaped trend was consistent for both female and male students.

CONCLUSION

Sleep duration appears to be a transdiagnostic marker for mental health in young adults.

Shorter self-reported sleep duration is associated with worse virtual spatial navigation performance in men

Sleep has been shown to impact navigation ability. However, it remains unclear how different sleep-related variables may be independently associated with spatial navigation performance, and as to whether gender may play a role in these associations. We used a mobile video game app, Sea Hero Quest (SHQ), to measure wayfinding ability in US-based participants. Wayfinding performance on SHQ has been shown to correlate with real-world wayfinding. Participants were asked to report their sleep duration, quality, daytime sleepiness and nap frequency and duration on a typical night (n = 766, 335 men, 431 women, mean age = 26.5 years, range = 18-59 years). A multiple linear regression was used to identify which self-reported sleep variables were independently associated with wayfinding performance. Shorter self-reported sleep durations were significantly associated with worse wayfinding performance in men only. Other self-reported sleep variables showed non-significant trends of association with wayfinding performance. When removing non-typical sleepers (< 6 or > 9 h of sleep on a typical night), the significant association between sleep duration and spatial navigation performance in men was no longer present. These findings from U.S.-based participants suggest that a longer self-reported sleep duration may be an important contributor to successful navigation ability in men.

[Body image perception, socioeconomic characteristics, and lifestyle in women participating in ELSA-Brasil in Bahia, Brazil]

Body image distortion is an alteration in the perception of the body that can have repercussions on health. This study aims to estimate the prevalence of body image accuracy and distortion among women participating in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) living in Bahia State, Brazil, and to investigate associations with socioeconomic characteristics, lifestyle, and gynecological care seeking. A total of 609 women aged 50 to 69 years participated in the study, who answered face-to-face questionnaires from 2012 to 2014. The Stunkard silhouette scale was used to investigate accurate or distorted perception for more or less weight. The relative risk ratio (RR) was calculated by multinomial logistic regression using Stata 13. Most participants have an accurate perception of their own bodies (53.7%). Among those with distorted perception, there is a tendency to distort towards less weight (38.1%). In the multinomial regression analysis, the variables race/skin color and education remained associated with the distortion towards underweight. The race/skin color variable was positively associated with the distortion towards underweight among Mixed-race women (RR = 1.89; 95%CI: 1.13-3.16) and black (RR = 2.10; 95%CI: 1.25-3.55), while the education variable among those with up to high school education (RR = 1.65; 95%CI: 1.18-2.33). There were no associations with the other variables or with distortion for more weight. The results contribute to explaining the relationships between body image perception and socioeconomic factors, revealing that women of different races/skin colors and varying educational levels are influenced in different ways by social discourses, impacting the perception of their body image.

Comprehensive assessment of sleep duration, insomnia, and brain structure within the UK Biobank cohort

STUDY OBJECTIVES

To assess for associations between sleeping more than or less than recommended by the National Sleep Foundation (NSF), and self-reported insomnia, with brain structure.

METHODS

Data from the UK Biobank cohort were analyzed (N between 9K and 32K, dependent on availability, aged 44 to 82 years). Sleep measures included self-reported adherence to NSF guidelines on sleep duration (sleeping between 7 and 9 hours per night), and self-reported difficulty falling or staying asleep (insomnia). Brain structural measures included global and regional cortical or subcortical morphometry (thickness, surface area, volume), global and tract-related white matter microstructure, brain age gap (difference between chronological age and age estimated from brain scan), and total volume of white matter lesions.

RESULTS

Longer-than-recommended sleep duration was associated with lower overall grey and white matter volumes, lower global and regional cortical thickness and volume measures, higher brain age gap, higher volume of white matter lesions, higher mean diffusivity globally and in thalamic and association fibers, and lower volume of the hippocampus. Shorter-than-recommended sleep duration was related to higher global and cerebellar white matter volumes, lower global and regional cortical surface areas, and lower fractional anisotropy in projection fibers. Self-reported insomnia was associated with higher global gray and white matter volumes, and with higher volumes of the amygdala, hippocampus, and putamen.

CONCLUSIONS

Sleeping longer than recommended by the NSF is associated with a wide range of differences in brain structure, potentially indicative of poorer brain health. Sleeping less than recommended is distinctly associated with lower cortical surface areas. Future studies should assess the potential mechanisms of these differences and investigate long sleep duration as a putative marker of brain health.

Linking brain structure, cognition, and sleep: insights from clinical data

STUDY OBJECTIVES

To use relatively noisy routinely collected clinical data (brain magnetic resonance imaging (MRI) data, clinical polysomnography (PSG) recordings, and neuropsychological testing), to investigate hypothesis-driven and data-driven relationships between brain physiology, structure, and cognition.

METHODS

We analyzed data from patients with clinical PSG, brain MRI, and neuropsychological evaluations. SynthSeg, a neural network-based tool, provided high-quality segmentations despite noise. A priori hypotheses explored associations between brain function (measured by PSG) and brain structure (measured by MRI). Associations with cognitive scores and dementia status were studied. An exploratory data-driven approach investigated age-structure-physiology-cognition links.

RESULTS

Six hundred and twenty-three patients with sleep PSG and brain MRI data were included in this study; 160 with cognitive evaluations. Three hundred and forty-two participants (55%) were female, and age interquartile range was 52 to 69 years. Thirty-six individuals were diagnosed with dementia, 71 with mild cognitive impairment, and 326 with major depression. One hundred and fifteen individuals were evaluated for insomnia and 138 participants had an apnea-hypopnea index equal to or greater than 15. Total PSG delta power correlated positively with frontal lobe/thalamic volumes, and sleep spindle density with thalamic volume. rapid eye movement (REM) duration and amygdala volume were positively associated with cognition. Patients with dementia showed significant differences in five brain structure volumes. REM duration, spindle, and slow-oscillation features had strong associations with cognition and brain structure volumes. PSG and MRI features in combination predicted chronological age (R2 = 0.67) and cognition (R2 = 0.40).

CONCLUSIONS

Routine clinical data holds extended value in understanding and even clinically using brain-sleep-cognition relationships.

Short sleep duration is associated with worse quality of life in Parkinson's disease: A multicenter cross-sectional study

OBJECTIVE

To characterize sleep duration and investigate its association with quality of life among Parkinson's Disease (PD) patients.

METHODS

In this multicenter cross-sectional study, 970 PD patients were divided into five groups based on self-reported sleep duration: <5, ≥5 to <6, ≥6 to <7, ≥7 to ≤8, and >8 h. The quality of life was evaluated using the 39-Item Parkinson's Disease Questionnaire (PDQ-39). Multivariable linear regression analysis, subgroup analysis, and mediation analysis were conducted to examine the association between sleep duration and quality of life.

RESULTS

In multivariable linear regression model, patients with sleep duration (<5 h) had significantly higher PDQ-39 scores (β = 8.132, 95 % CI: 3.99 to 12.266), especially in mobility, activities of daily living, emotional well-being, stigma, social support, cognition, communication, and bodily discomfort (p < 0.05). The association between sleep duration (<5 h) and worse quality of life was more pronounced in patients with higher HY stage, longer disease duration, and sleep disorders. Moreover, a significant indirect effect of sleep duration (<5 h) on quality of life was observed, with UPDRS I, UPDRS II, and UPDRS IV scores acting as mediators.

CONCLUSIONS

Short sleep duration (<5 h) is associated with worse quality of life among PD patients. This association was stronger among patients with advanced PD and sleep disorders, while non-motor symptoms and motor complications were identified as significant mediators in this association. These findings highlight the significance of adequate sleep duration and suitable interventions for sleep may help improve quality of life.

Modeling genotype-protein interaction and correlation for Alzheimer's disease: a multi-omics imaging genetics study

Integrating and analyzing multiple omics data sets, including genomics, proteomics and radiomics, can significantly advance researchers' comprehensive understanding of Alzheimer's disease (AD). However, current methodologies primarily focus on the main effects of genetic variation and protein, overlooking non-additive effects such as genotype-protein interaction (GPI) and correlation patterns in brain imaging genetics studies. Importantly, these non-additive effects could contribute to intermediate imaging phenotypes, finally leading to disease occurrence. In general, the interaction between genetic variations and proteins, and their correlations are two distinct biological effects, and thus disentangling the two effects for heritable imaging phenotypes is of great interest and need. Unfortunately, this issue has been largely unexploited. In this paper, to fill this gap, we propose $\textbf{M}$ulti-$\textbf{T}$ask $\textbf{G}$enotype-$\textbf{P}$rotein $\textbf{I}$nteraction and $\textbf{C}$orrelation disentangling method ($\textbf{MT-GPIC}$) to identify GPI and extract correlation patterns between them. To ensure stability and interpretability, we use novel and off-the-shelf penalties to identify meaningful genetic risk factors, as well as exploit the interconnectedness of different brain regions. Additionally, since computing GPI poses a high computational burden, we develop a fast optimization strategy for solving MT-GPIC, which is guaranteed to converge. Experimental results on the Alzheimer's Disease Neuroimaging Initiative data set show that MT-GPIC achieves higher correlation coefficients and classification accuracy than state-of-the-art methods. Moreover, our approach could effectively identify interpretable phenotype-related GPI and correlation patterns in high-dimensional omics data sets. These findings not only enhance the diagnostic accuracy but also contribute valuable insights into the underlying pathogenic mechanisms of AD.

Volume of the Dentate Gyrus/CA4 Hippocampal subfield mediates the interplay between sleep quality and depressive symptoms

Background

Emerging evidence increasingly suggests that poor sleep quality is associated with depressive symptoms. The hippocampus might play a crucial role in the interplay between sleep disturbance and depressive symptomatology, e.g., hippocampal atrophy is typically seen in both insomnia disorder and depression. Thus, examining the role of hippocampal volume in the interplay between poor sleep quality and depressive symptoms in large healthy populations is vital.

Methods

We investigated the association between self-reported sleep quality, depressive symptoms, and hippocampal total and subfields' volumes in 1603 healthy young adults from the Behavioral Brain Research Project. Mediation analysis explored the mediating role of hippocampal volumes between sleep quality and depressive symptoms.

Results

Self-reported sleep quality and depressive symptoms were positively correlated. In addition, it negatively related to three hippocampal subfields but not total hippocampal volume. In particular, hippocampal subfield DG and CA4 volumes mediated the interrelationship between poor sleep quality and depressive symptoms.

Conclusions

Our findings improved the current understanding of the relationship between sleep disturbance, depressive symptomatology, and hippocampal subfields in healthy populations. Considering the crucial role of DG in hippocampal neurogenesis, our results suggest that poor sleep quality may contribute to depression through a reduction of DG volume leading to impaired neurogenesis which is crucial for the regulation of mood.

A nationwide study on sleep complaints and associated factors in older adults: ELSI-Brazil

Sleep problems, such as difficulty falling asleep, staying asleep, early awakening with failure to continue sleep, and altered sleep-wake cycle, are common in the general population. This cross-sectional study with 6,929 older adults (≥ 60 years) aimed to estimate the prevalence of different types of sleep problems, their associated factors, and the population-attributable fraction of associated factors among older adults. The outcome variables consisted of self-reported sleep problems: insomnia (initial, intermediate, late, and any type of insomnia), poor sleep quality, and daytime sleepiness. The independent variables were sociodemographic and behavioral characteristics and health conditions. The prevalence proportions were initial insomnia (49.1%), intermediate insomnia (49.2%), late insomnia (45.9%), any type of insomnia (58.6%), poor sleep quality (15.6%), and daytime sleepiness (38.4%). Female sex, presence of two or more chronic diseases, not eating the recommended amount of fruits and vegetables, and regular and bad/very bad self-rated health were positively associated with the sleep problems investigated. Consuming alcohol once a month or more was inversely associated with initial insomnia. Population attributable fraction estimates ranged from 3% to 19% considering two or more chronic diseases, not eating the recommended amount of fruits and vegetables, and regular and bad/very bad self-rated health. High prevalence of self-reported sleep problems was evinced in older adults. These results can be useful to guide public health services in the creation of informational, evaluative, and screening strategies for sleep problems in older Brazilian adults.

No phenotypic or genotypic evidence for a link between sleep duration and brain atrophy

Short sleep is held to cause poorer brain health, but is short sleep associated with higher rates of brain structural decline? Analysing 8,153 longitudinal MRIs from 3,893 healthy adults, we found no evidence for an association between sleep duration and brain atrophy. In contrast, cross-sectional analyses (51,295 observations) showed inverse U-shaped relationships, where a duration of 6.5 (95% confidence interval, (5.7, 7.3)) hours was associated with the thickest cortex and largest volumes relative to intracranial volume. This fits converging evidence from research on mortality, health and cognition that points to roughly seven hours being associated with good health. Genome-wide association analyses suggested that genes associated with longer sleep for below-average sleepers were linked to shorter sleep for above-average sleepers. Mendelian randomization did not yield evidence for causal impacts of sleep on brain structure. The combined results challenge the notion that habitual short sleep causes brain atrophy, suggesting that normal brains promote adequate sleep duration-which is shorter than current recommendations.

Total sleep duration and daytime napping in relation to dementia detection risk: Results from the Million Women Study

INTRODUCTION

There is inconsistent evidence on the associations of sleep duration and daytime napping with dementia risk.

METHODS

In the Million Women Study, a total of 830,716 women (mean age, 60 years) were asked about sleep duration (<7, 7-8, >8 hours) and daytime napping (rarely/never, sometimes, usually) in median year 2001, and were followed for the first hospital record with any mention of dementia. Cox regression estimated dementia detection risk ratios (RRs) during 17-year follow-up in 5-year intervals.

RESULTS

With 34,576 dementia cases, there was strong attenuation over follow-up in the RRs related to long sleep duration (>8 vs 7-8 hours) and usually napping (vs rarely/never). Short sleep duration was modestly, positively associated with dementia in the long term (RR = 1.08, 95% confidence interval [CI] 1.04-1.12).

DISCUSSION

There was little evidence to suggest that long sleep duration and regular napping are associated with long-term dementia risk. Short sleep duration was modestly associated with dementia risk, but residual confounding cannot be excluded.

HIGHLIGHTS

Long sleep duration was not associated with long-term dementia risk. Daytime napping was not associated with long-term dementia risk. There is some evidence for a small higher risk of dementia related to short sleep.

Association between vmPFC gray matter volume and smoking initiation in adolescents

Smoking of cigarettes among young adolescents is a pressing public health issue. However, the neural mechanisms underlying smoking initiation and sustenance during adolescence, especially the potential causal interactions between altered brain development and smoking behaviour, remain elusive. Here, using large longitudinal adolescence imaging genetic cohorts, we identify associations between left ventromedial prefrontal cortex (vmPFC) gray matter volume (GMV) and subsequent self-reported smoking initiation, and between right vmPFC GMV and the maintenance of smoking behaviour. Rule-breaking behaviour mediates the association between smaller left vmPFC GMV and smoking behaviour based on longitudinal cross-lagged analysis and Mendelian randomisation. In contrast, smoking behaviour associated longitudinal covariation of right vmPFC GMV and sensation seeking (especially hedonic experience) highlights a potential reward-based mechanism for sustaining addictive behaviour. Taken together, our findings reveal vmPFC GMV as a possible biomarker for the early stages of nicotine addiction, with implications for its prevention and treatment.

Sleep condition detection and assessment with optical fiber interferometer based on machine learning

The prevalence of sleep disorders has increased because of the fast-paced and stressful modern lifestyle, negatively impacting the quality of human life and work efficiency. It is crucial to address sleep problems. However, the current practice of diagnosing sleep disorders using polysomnography (PSG) has limitations such as complexity, large equipment, and low portability, hindering its practicality for daily use. To overcome these challenges, in this article an optical fiber sensor is proposed as a viable solution for sleep monitoring. This device offers benefits like low power consumption, non-invasiveness, absence of interference, and real-time health monitoring. We introduce the sensor with an optical fiber interferometer to capture ballistocardiography (BCG) and electrocardiogram (ECG) signals from the human body. Furthermore, a new machine learning method is proposed for sleep condition detection. Experimental results demonstrate the superior performance of this architecture and the proposed model in monitoring and assessing sleep quality.

Physical Activity Levels, Eating Habits, and Well-Being Measures in Students of Healthcare Degrees in the Second Year of the COVID-19 Pandemic

BACKGROUND

When the first cases of COVID-19 (caused by SARS-CoV-2 virus infection) were discovered, exceptional norms to fight the spread of the virus were established by applying movement restrictions (lockdown) in many countries. These unprecedented norms led to sedentary behaviours and less healthy diets which could persist for much longer after lockdown. The aim of this study was to analyse the physical activity, eating habits, self-perceived well-being, and toxic habits, as well as the perceived changes of these habits with respect to the pre-pandemic period, in a population of university students in the second year of the COVID-19 pandemic.

METHODS

A single-centre, cross-sectional study was conducted in a population of university students of healthcare degrees. A total of 961 students (639 (66.5%) women and 322 (33.5%) men) signed the informed consent and completed the questionnaire. The study was conducted through an anonymous survey, which was voluntarily self-completed by the students on an online platform. The questionnaire was based on the Spanish Health Survey and it was divided into six main parts: demographic and anthropometric characteristics, physical activity, eating habits, well-being measures (sleeping habits, health state, and stress), toxic habits, and perception of the influence of the COVID-19 pandemic on the variables described.

RESULTS AND CONCLUSIONS

The results showed that, during the second year of the pandemic, statistically significant dependence was identified for those students that showed higher levels of physical activity with greater perceived physical activity (p < 0.05), healthier eating habits (p < 0.05), and a better self-perceived health state (p < 0.05), with respect to the 12 months before the COVID-19 pandemic. On the other hand, there was a negative correlation between the sedentary students and greater perceived physical activity (p < 0.05). With regard to toxic habits and physical activity, a significant correlation was only detected between sedentary behaviour and cocaine consumption (p < 0.05). Analysing eating habits, it was observed that the students who smoked, consumed alcohol, and binge drank had low adherence to the Mediterranean diet (p < 0.05). In addition, those students with high stress levels slept less than 7 h (p < 0.05).

Sleep quality and sleep duration predict brain microstructure among community-dwelling older adults

Although poor sleep quality and extreme sleep durations have been associated with brain atrophy and dementia, it is unclear whether sleep disturbances contribute to neural injury in the absence of neurodegeneration and cognitive impairment. In 146 dementia-free older adults of the Rancho Bernardo Study of Healthy Aging (76.7 ± 7.8 years at MRI), we examined associations of restriction spectrum imaging metrics of brain microstructure with self-reported sleep quality 6.3 ± 0.7 years prior, and with sleep duration reported 25, 15 and 9 years prior. Worse sleep quality predicted lower white matter restricted isotropic diffusion and neurite density and higher amygdala free water, with stronger associations between poor sleep quality and abnormal microstructure for men. Among women only, short or long sleep duration 25 and 15 years before MRI predicted lower white matter restricted isotropic diffusion and increased free water. Associations persisted after accounting for associated health and lifestyle factors. Sleep patterns were not related to brain volume or cortical thickness. Optimizing sleep behaviors throughout the life-course may help to preserve healthy brain aging.

Association of Self-Reported Sleep Characteristics and Hip Fracture: Observational and Mendelian Randomization Studies

Previous observational studies on the relationship between sleep characteristics and fracture have yielded contradictory results. The goal of this study was to replicate the findings in a large longitudinal cohort and then conduct a Mendelian randomization (MR) analysis to infer the causality between sleep behaviors and fracture risk. Based on data from the China Health and Retirement Longitudinal Study (CHARLS) including 17,708 participants, we found that individuals with short sleep duration (<5 h) (OR [odds ratio] = 1.62, 95% CI: 1.07-2.44) or restless sleep (OR = 1.55, 95% CI: 1.10-2.19) have a higher risk of hip fracture. A U-shaped relationship between nighttime sleep duration and hip fracture risk (p-nonlinear = 0.01) was observed using restricted cubic spline regression analysis. Through joint effect analysis, we found that participants with short sleep duration (<5 h) combined with midday napping could significantly decrease hip fracture incidence. We further inferred the causal relationship between self-reported sleep behaviors and hip fracture using the MR approach. Among four sleep phenotypic parameters (sleep duration, daytime napping, chronotype, and insomnia), we found a modest causal relationship between sleep duration and fracture (OR = 0.69, 95% CI: 0.48 to 0.99, p = 0.04). However, no causal relationship was observed for other sleep traits. In conclusion, our findings suggest that short sleep duration has a potential detrimental effect on hip fracture. Improving sleep patterns is of significance for developing hip fracture preventive strategies in the middle-aged and the elderly populations.

Mediating role of depressive symptoms on the relationship between sleep duration and cognitive function

Although some studies have shown the association between sleep duration and cognitive impairment is positive, the mechanism explaining how sleep duration is linked to cognition remains poor understood. The current study aims to explore it among Chinese population. A cross-sectional study of 12,589 participants aged 45 or over was conducted, cognition was assessed by three measures to capture mental intactness, episodic memory, and visuospatial abilities. The Center for Epidemiologic Studies Depression Scale 10 (CES-D₁₀) was administered during the face-to-face survey to assess depressive status. Sleep duration was reported by the participants themselves. Partial correlation and linear regression were used to explore the association between sleep duration, cognition, and depression. The Bootstrap methods PROCESS program was used to detect the mediation effect of depression. Sleep duration was positively correlated with cognition and negatively with depression (p < 0.01). The CES-D₁₀ score (r = - 0.13, p < 0.01) was negatively correlated with cognitive function. Linear regression analysis showed sleep duration was positively associated with cognition (p = 0.001). When depressive symptoms were considered, the association between sleep duration and cognition lost significance (p = 0.468). Depressive symptoms have mediated the relationship between sleep duration and cognitive function. The findings revealed that the relationship between sleep duration and cognition is mainly explained by depressive symptoms and may provide new ideas for interventions for cognitive dysfunction.

Association between daytime napping and cognitive impairment among Chinese older population: a cross-sectional study

BACKGROUND

Both napping and nighttime sleep duration have been reported to be associated with cognitive function in older adults, whereas little is known about the association between daytime napping and cognitive impairment in different nighttime sleep duration subgroups. This study aimed to explore the correlation between daytime napping and cognitive impairment across nighttime sleep duration subgroups.

METHODS

A cross-sectional study was conducted by using the fourth survey of China Health and Retirement Longitudinal Study (CHARLS). We utilized the Mini-Mental State Examination (MMSE) scale to define cognitive impairment, and the daytime napping and nighttime sleep duration was self-reported by individuals. We applied the Restricted Cubic Spline (RCS) to analysis the dose-response relationships between daytime napping and cognitive impairment. And the multivariate Logistic Regression Model (LRM) was performed to evaluate the association of daytime napping and cognitive impairment.

RESULTS

A total of 3,052 individuals were included, of which 769 were cognitive impairment. The RCS showed there were non-linear association between daytime napping and cognitive impairment in all participants group and longer nighttime sleep duration subgroup (PNon-linear < 0.05, PDaytime napping < 0.05). The LRM revealed no napping (OR = 1.62, 95%CI 1.14-2.30) and excessive napping (1.64 95%CI 1.09-2.48) were related to cognitive impairment in longer nighttime sleep duration subgroup.

CONCLUSIONS

Daytime napping had nonlinear association with cognitive impairment in Chinese elderly population. No napping and excessive daytime napping (>90 minutes) were related to cognitive impairment in participants with 7 and more hours nighttime sleep duration.

Genetic associations between sleep traits and cognitive ageing outcomes in the Hispanic Community Health Study/Study of Latinos

BACKGROUND

Sleep phenotypes have been reported to be associated with cognitive ageing outcomes. However, there is limited research using genetic variants as proxies for sleep traits to study their associations. We estimated associations between Polygenic Risk Scores (PRSs) for sleep duration, insomnia, daytime sleepiness, and obstructive sleep apnoea (OSA) and measures of cogntive ageing in Hispanic/Latino adults.

METHODS

We used summary statistics from published genome-wide association studies to construct PRSs representing the genetic basis of each sleep trait, then we studied the association of the PRSs of the sleep phenotypes with cognitive outcomes in the Hispanic Community Healthy Study/Study of Latinos. The primary model adjusted for age, sex, study centre, and measures of genetic ancestry. Associations are highlighted if their p-value <0.05.

FINDINGS

Higher PRS for insomnia was associated with lower global cognitive function and higher risk of mild cognitive impairment (MCI) (OR = 1.20, 95% CI [1.06, 1.36]). Higher PRS for daytime sleepiness was also associated with increased MCI risk (OR = 1.14, 95% CI [1.02, 1.28]). Sleep duration PRS was associated with reduced MCI risk among short and normal sleepers, while among long sleepers it was associated with reduced global cognitive function and with increased MCI risk (OR = 1.40, 95% CI [1.10, 1.78]). Furthermore, adjustment of analyses for the measured sleep phenotypes and APOE-ε4 allele had minor effects on the PRS associations with the cognitive outcomes.

INTERPRETATION

Genetic measures underlying insomnia, daytime sleepiness, and sleep duration are associated with MCI risk. Genetic and self-reported sleep duration interact in their effect on MCI.

FUNDING

Described in Acknowledgments.

Differences in Subjective and Objective Cognitive Decline Outcomes Are Associated with Modifiable Protective Factors: A 4-Year Longitudinal Study

Subjective cognitive decline (SCD) in older adults has been identified as a risk factor for dementia. However, the literature is inconsistent, and the underlying mechanisms are not well understood. We aimed to determine whether older adults with SCD had more modifiable protective factors against the risk of dementia and a lower risk of developing objective cognitive decline (OCD). We included 4363 older adults (71.7 ± 5.3 [mean ± standard deviation] years of age; 2239 women) from the National Center for Geriatrics and Gerontology Study of Geriatric Syndromes. SCD, OCD, and protective factors against dementia, such as lifestyle and activity, were assessed using interviews and objective cognitive-assessment tools. Based on initial cognitive status, participants were categorized into normal cognition, SCD-only, OCD-only, and both SCD and OCD groups. After 4 years, participants were classified as having either no impairment or mild or global cognitive impairment (i.e., OCD). Binomial logistic regression analyses were performed with the cognitive statuses of the groups at follow-up and baseline as the dependent and independent variables, respectively. After adjusting for potential confounding factors, we found that the SCD-only group had more modifiable protective factors against the risk of dementia than the OCD-only group. Community-dwelling older adults with normal cognition or those part of the SCD-only group had a lower risk of developing OCD during the 4-year follow-up, which may have been due to having more modifiable protective factors against the risk of dementia. Additionally, these factors may contribute to the inconsistencies in the literature on SCD outcomes.

Hearing impairment is associated with cognitive decline, brain atrophy and tau pathology

BACKGROUND

Hearing impairment was recently identified as the most prominent risk factor for dementia. However, the mechanisms underlying the link between hearing impairment and dementia are still unclear.

METHODS

We investigated the association of hearing performance with cognitive function, brain structure and cerebrospinal fluid (CSF) proteins in cross-sectional, longitudinal, mediation and genetic association analyses across the UK Biobank (N = 165,550), the Chinese Alzheimer's Biomarker and Lifestyle (CABLE, N = 863) study, and the Alzheimer's Disease Neuroimaging Initiative (ADNI, N = 1770) database.

FINDINGS

Poor hearing performance was associated with worse cognitive function in the UK Biobank and in the CABLE study. Hearing impairment was significantly related to lower volume of temporal cortex, hippocampus, inferior parietal lobe, precuneus, etc., and to lower integrity of white matter (WM) tracts. Furthermore, a higher polygenic risk score (PRS) for hearing impairment was strongly associated with lower cognitive function, lower volume of gray matter, and lower integrity of WM tracts. Moreover, hearing impairment was correlated with a high level of CSF tau protein in the CABLE study and in the ADNI database. Finally, mediation analyses showed that brain atrophy and tau pathology partly mediated the association between hearing impairment and cognitive decline.

INTERPRETATION

Hearing impairment is associated with cognitive decline, brain atrophy and tau pathology, and hearing impairment may reflect the risk for cognitive decline and dementia as it is related to bran atrophy and tau accumulation in brain. However, it is necessary to assess the mechanism in future animal studies.

FUNDING

A full list of funding bodies that supported this study can be found in the Acknowledgements section.

Toxic Habits and Well-Being Measures in Spanish Healthcare University Students during the COVID-19 Pandemic

BACKGROUND

Unhealthy lifestyles are strongly entrenched in healthcare universities and have sometimes been linked to stress or lack of sleep. This study investigated the prevalence of toxic habits (smoking, patterns of harmful alcohol use, and illicit drug use), stress levels, perceived health status, and sleep duration and assessed the connections between toxic habits and said well-being measures, as well as healthcare students' perception of the influence of the COVID-19 pandemic on these health-related behaviors.

METHODS

In a cross-sectional study, healthcare students from Alfonso X University (Spain) completed a health survey composed of Alcohol Use Disorders Identification Test (AUDIT-C), Perceived Stress Scale (PSS-10), self-perceived health status, and the number of hours of sleep.

RESULTS

A total of 997 healthcare students completed the survey, of which 982 were analyzed. Being a smoker (32.2%) was associated with worse health status and insufficient sleep. Risk drinkers (33.2%) were associated with being female, and the consumption of cannabinoids (6.7%), with being male. These three toxic habits were related to each other. High levels of stress (28.2%) were correlated with worse ratings in the perception of health status (29.2%) and with insufficient sleep (45.8%), and all of them were associated with the female sex. Respectively, 49.3% and 44.2% of students recognized a worsening in their perception of stress and their sleep habits during the pandemic.

CONCLUSION

Healthcare universities must carry out health promotion programs for stress management, sleep habits, and unhealthy lifestyles.

Sleep function: an evolutionary perspective

Prospective epidemiological studies in industrial societies indicate that 7 h of sleep per night in people aged 18 years or older is optimum, with higher and lower amounts of sleep predicting a shorter lifespan. Humans living a hunter-gatherer lifestyle (eg, tribal groups) sleep for 6-8 h per night, with the longest sleep durations in winter. The prevalence of insomnia in hunter-gatherer populations is low (around 2%) compared with the prevalence of insomnia in industrial societies (around 10-30%). Sleep deprivation studies, which are done to gain insights into sleep function, are often confounded by the effects of stress. Consideration of the duration of spontaneous daily sleep across species of mammals, which ranges from 2 h to 20 h, can provide important insights into sleep function without the stress of deprivation. Sleep duration is not related to brain size or cognitive ability. Rather, sleep duration across species is associated with their ecological niche and feeding requirements, indicating a role for wake-sleep balance in food acquisition and energy conservation. Brain temperature drops from waking levels during non-rapid eye movement (non-REM) sleep and rises during REM sleep. Average daily REM sleep time of homeotherm orders is negatively correlated with average body and brain temperature, with the largest amount of REM sleep in egg laying (monotreme) mammals, moderate amounts in pouched (marsupial) mammals, lower amounts in placental mammals, and the lowest amounts in birds. REM sleep might, therefore, have a key role in the regulation of temperature and metabolism of the brain during sleep and in the facilitation of alert awakening.

Association between Self-Reported Prior Night's Sleep and Single-Task Gait in Healthy, Young Adults: A Study Using Machine Learning

Failure to obtain the recommended 7−9 h of sleep has been associated with injuries in youth and adults. However, most research on the influence of prior night’s sleep and gait has been conducted on older adults and clinical populations. Therefore, the objective of this study was to identify individuals who experience partial sleep deprivation and/or sleep extension the prior night using single task gait. Participants (n = 123, age 24.3 ± 4.0 years; 65% female) agreed to participate in this study. Self-reported sleep duration of the night prior to testing was collected. Gait data was collected with inertial sensors during a 2 min walk test. Group differences (<7 h and >9 h, poor sleepers; 7−9 h, good sleepers) in gait characteristics were assessed using machine learning and a post-hoc ANCOVA. Results indicated a correlation (r = 0.79) between gait parameters and prior night’s sleep. The most accurate machine learning model was a Random Forest Classifier using the top 9 features, which had a mean accuracy of 65.03%. Our findings suggest that good sleepers had more asymmetrical gait patterns and were better at maintaining gait speed than poor sleepers. Further research with larger subject sizes is needed to develop more accurate machine learning models to identify prior night’s sleep using single-task gait.

[Neurodegenerative diseases and brain aging]

Neurodegenerative diseases such as Alzheimer's, Parkinson's or Amyotrophic Lateral Sclerosis are generally of sporadic origin, but the risk of being affected increases dramatically with age. Progress in understanding brain aging contributes to define precisely the relationships between aging associated physiological and pathological processes. Aging is induced by various stresses, which turn somatic cells to a senescent state. Senescent cells cannot divide but acquire a typical phenotype and release chemicals that trigger inflammation. In the brain, glial cells such as astrocytes or microglia as well as neurons are affected. Dendritic branching declines, resulting in a decrease of synaptic plasticity and cognitive performances, associated with brain aging. Aging alters also glymphatic washing, the process by which brain catabolites are eliminated. The neurodegenerative diseases are proteinopathies resulting from pathological conformations of physiological proteins. Normally washed by the glymphatic flux, these proteins accumulate and aggregate in its absence and then trigger neuron death.

Association between sleep and multimorbidity in Chinese elderly: Results from the Chinese Longitudinal Healthy Longevity Survey (CLHLS)

OBJECTIVE

Abnormal sleep duration and poor sleep quality were associated with multiple diseases. However, the association between sleep behavior (including sleep duration and quality) and multimorbidity among the elderly remains unclear. Thus, our study aimed to explore this association in the Chinese elderly.

METHODS

We conducted a cross-sectional study using data from the Chinese Longitudinal Healthy Longevity Survey (2014 wave). Nineteen chronic diseases were used to measure multimorbidity. Self-reported nighttime sleep duration and sleep quality were used as exposures. Multivariate logistic regression analysis and stratification were used to explore the association between sleep behavior and multimorbidity in different groups. Restrictive cubic splines were used to examine the exposure-response relationship.

RESULTS

Compared with those with nighttime sleep duration between 7 and 9 h, participants with shorter (<7 h) and longer (>9 h) sleep duration had a higher prevalence of multimorbidity (odds ratio [OR], 95% confidence interval [CI] were 1.38, 1.18-1.61 and 1.30, 1.09-1.56 respectively). Besides, poor sleep quality (OR = 2.25, 95% CI:1.82-2.72) and moderate sleep quality (OR = 1.35, 95% CI:1.16-1.58) were positively associated with multimorbidity.

CONCLUSIONS

Although the role of sleep behavior in multimorbidity has not been fully understood, this study highlighted the importance of normal nighttime sleep duration and good sleep quality in preventing multimorbidity.