Association between rest-activity rhythm and diabetic retinopathy among US middle-age and older diabetic adults.

Background: The disruption of circadian rhythm has been reported to aggravate the progression of diabetic retinopathy (DR). Rest-activity rhythm (RAR) is a widely used method for measuring individual circadian time influencing behavior. In this study, we sought to explore the potential association between RAR and the risk of DR. Methods: Diabetic participants aged over 40 from 2011-2014 National Health and Nutrition Examination Survey (NHANES) were enrolled. Data from the wearable device ActiGraph GT3X was used to generate RAR metrics, including interdaily stability (IS), intradaily variability (IV), most active 10-hour period (M10), least active 5-hour period (L5), and Relative amplitude (RA). Weighted multivariable logistic regression analysis and restricted cubic spline analysis were conducted to examine the association between RAR metrics and DR risk. Sensitivity analysis was also conducted to examine the robustness of the findings. An unsupervised K-means clustering analysis was conducted to identify patterns in IV and M10. Results: A total of 1,096 diabetic participants were enrolled, with a DR prevalence of 20.53%. The mean age of participants was 62.3 years, with 49.57% being male. After adjusting covariates, IV was positively associated with DR (ß: 3.527, 95%CI: 1.371-9.073). Compared with the lowest quintile of IV, the highest quintile of IV had 136% higher odds of DR. In contrast, M10 was negatively associated with DR (ß: 0.902, 95%CI: 0.828-0.982), with participants in the highest M10 quintile showing 48.8% lower odds of DR. Restricted cubic spline analysis confirmed that these associations were linear. Meanwhile, sensitivity analysis confirmed the robustness. K-means clustering identified three distinct clusters, with participants in Cluster C (high-IV, low-M10) had a significantly higher risk of DR comparing with Cluster A (low-IV, high-M10). Conclusion: A more fragmented rhythm and lower peak activity level might be associated with an increased risk of DR. These findings indicate that maintaining a more rhythmic sleep-activity behavior might mitigate the development of DR. Further research is necessary to establish causality and understand the underlying mechanisms, and focus on whether interventions designed to enhance daily rhythm stability and increase diurnal activity level can effectively mitigate the risk of progression of DR.

Exploration of sleep quality and rest-activity rhythms characteristics in Bilateral Vestibulopathy patients.

Sleep and circadian timing systems are constantly regulated by both photic and non-photic signals. Connections between the vestibular nuclei and the biological clock raise the question of the effect of peripheral vestibular loss on daily rhythms, such as the sleep-wake cycle and circadian rhythm. To answer this question, we compared the sleep and rest-activity rhythm parameters of 15 patients with bilateral vestibulopathy (BVP) to those of 15 healthy controls. Sleep and rest-activity cycle were recorded by a device coupling actimetry with the heart rate and actigraphy at home over 7 days. Subjective sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI). Sleep efficiency and subjective sleep quality were significantly reduced, and sleep fragmentation was increased in BVP patients compared to controls. BVP patients displayed a damped amplitude of the rest-activity rhythm and higher sleep fragmentation, reflected by a higher nocturnal activity compared to controls. These results suggest that both rest-activity and sleep cycles are impaired in BVP patients compared to healthy controls. BVP patients seem to have greater difficulty maintaining good sleep at night compared to controls. BVP pathology appears to affect the sleep-wake cycle and disturb the circadian rhythm synchronization. Nevertheless, these results need further investigation to be confirmed, particularly with larger sample sizes.

Improvement of social frailty is associated with stability of nonparametric characteristics of the rest-activity rhythm and improvement of the usual walking ability in the elderly.

Our study, conducted between April 2022 and January 2024, was aimed at clarifying components of the rest-activity rhythm (RAR) involved in improvement of social frailty state before or after a 3-month multi-component exercise intervention in the elderly. Participants were recruited from the general population in Akita prefecture, Japan. We administered a four-item social frailty screening questionnaire to classify the severity of social frailty in each participant before and after the 3-month intervention. The RAR parameters were measured on an Actiwatch Spectrum Plus device worn by the subjects for 7 continuous days. As the final sample, 65 participants classified into the improved/maintained group (n = 36) or the deteriorated group (n = 29) according to the change in the social frailty classification after the intervention were included in the analysis. The results of a binomial logistic regression analysis showed significantly higher values of interdaily stability (IS) and usual walking speed at the post-test after the intervention. Based on our findings, we propose that stability of the rest-activity rhythm related to synchronization with external stimuli (such as social effect and physical activity) might have clinical impact on improvement of social frailty state in elderly community-dwellers.

Longitudinal association between accelerometer-derived rest-activity rhythm and atherosclerotic cardiovascular disease.

OBJECTIVE: Rest-activity rhythm is an essential behavior for human health. However, the association between rest-activity rhythm and atherosclerotic cardiovascular disease (ASCVD) risk remains unclear. Therefore, this study aimed to elucidate the association. METHODS: This study included 87,039 participants from the UK Biobank who had 7-day accelerometry data and were free of ASCVD at baseline. Relative amplitude was calculated as the difference between the most active continuous 10-h period (M10) and the least active continuous 5-h period (L5) in 24 h, and lower relative amplitude indicated the disruption of rest-activity rhythm. Cox proportional hazard model was used to examine the association of relative amplitude with ASCVD. Further, the linear association between relative amplitude and arterial stiffness measurements, including arterial stiffness index (ASI) and carotid intima-media thickness (cIMT), was examined. RESULTS: During a mean follow-up period of 6.80 ± 1.10 years, 2798 ASCVD cases were identified. A dose-response relationship was observed between relative amplitude and ASCVD risk (P for trend<0.001). The adjusted hazard ratio, for the highest vs the lowest quintile of relative amplitude, was 1.54 (95 % confidence interval: 1.31, 1.79). Further, we found significant association of lower relative amplitude with ASI and cIMT. The onset timing of M10 at ≤06:00, 09:00, 10:00, or ≥11:00, as opposed to the reference time of 07:00, was associated with higher ASCVD risk. CONCLUSIONS: Low rest-activity rhythm amplitude was associated with a higher risk of ASCVD. Rest-activity rhythm amplitude may provide a method to identify individuals at risk of ASCVD in public health and clinical practice.

Factors associated with the fragmentation and stability of the rest-activity rhythm in adults and older adults.

This cross-sectional study aimed to identify factors related to the fragmentation and stability of the rest-activity rhythm (RAR) in adults and older adults. It is part of a larger research project investigating aspects concerning sleep duration, quality, and disorders in a representative subsample of the population. Sociodemographic data, lifestyle, health habits and subjective sleep variables were obtained; RAR records were collected by means of actigraphy and analyzed using non-parametric variables (IS, IV, M10, L5, RA, sL5, and sM10). Study participants were 313 individuals with complete actigraphy records. There was a prevalence of older adults (50.2%) and females (51.1%). Females, individuals with 4-8 y of education, and those who used alcohol abusively exhibited lower RAR fragmentation. Higher fragmentation was observed in individuals who napped and those reporting poor sleep quality. Greater rhythm stability was evident in females, older adults, those with 4-8 y of education, and those who had a partner. Smokers demonstrated lower RAR stability. These findings may contribute valuable insights for decision-making aimed at preventing and treating issues related to fragmentation and instability of the rhythm and its possible consequences to health.

Associations between accelerometer-measured circadian rest-activity rhythm, brain structural and genetic mechanisms, and dementia.

AIM: Knowledge of how circadian rhythm influences brain health remains limited. We aimed to investigate the associations of accelerometer-measured circadian rest-activity rhythm (CRAR) with incident dementia, cognitive dysfunction, and structural brain abnormalities in the general population and underlying biological mechanisms. METHODS: Fifty-seven thousand five hundred and two participants aged over 60 years with accelerometer data were included to investigate the association of CRAR with incidental dementia. Non-parametric CRAR parameters were utilized, including activity level during active periods of the day (M10), activity level during rest periods of the day (L5), and the relative difference between the M10 and L5 (relative amplitude, RA). Associations of CRAR with cognitive dysfunction and brain structure were studied in a subset of participants. Neuroimaging-transcriptomics analysis was utilized to identify the underlying molecular mechanisms. RESULTS: Over 6.86 (4.94-8.78) years of follow-up, 494 participants developed dementia. The risk of incident dementia was associated with decreasing M10 (hazard ratio [HR] 1.45; 95% conference interval [CI], 1.28-1.64) and RA (HR 1.37; 95% CI, 1.28-1.64), increasing L5 (HR 1.14, 95% CI 1.07-1.21) and advanced L5 onset time (HR 1.12; 95% CI, 1.02-1.23). The detrimental associations were exacerbated by APOE ε4 status and age (>65 years). Decreased RA was associated with lower processing speed (Beta -0.04; SE 0.011), predominantly mediated by abnormalities in subcortical regions and white matter microstructure. The genes underlying CRAR-related brain regional structure variation were enriched for synaptic function. CONCLUSIONS: Our study underscores the potential of intervention targeting at maintaining a healthy CRAR pattern to prevent dementia risk.

Sleep-wake behavioral characteristics associated with depression symptoms: findings from the Multi-Ethnic Study of Atherosclerosis.

STUDY OBJECTIVES: To help prioritize target/groups for experimental intervention studies, we characterized cross-sectional associations between 24-hour sleep-wake measures and depression symptoms, and evaluated if similar sleep-wake-depression relationships existed in people with and without higher insomnia severity. METHODS: Participants had ≥3 days of actigraphy data (n = 1884; mean age = 68.6/SD = 9.1; 54.1% female). We extracted 18 sleep, activity, timing, rhythmicity, and fragmentation measures from actigraphy. We used individual and multivariable regressions with the outcome of clinically significant depression symptoms (Center for Epidemiologic Studies Depression Scale ≥ 16). We conducted sensitivity analyses in people with higher insomnia severity (top quartile of the Women's Health Initiative Insomnia Rating Scale total score). RESULTS: From separate models in the overall sample, the odds of having depression symptoms were higher with: later timing (e.g. activity onset time odds ratio [OR]/1 SD = 1.32; 95% confidence interval [CI]: 1.16 to 1.50), lower rhythmicity (e.g. pseudo-F OR/1 SD = 0.75; 95% CI: 0.66 to 0.85), less activity (e.g. amplitude OR/1 SD = 0.83; 95% CI: 0.72 to 0.95), and worse insomnia (OR/1 SD = 1.48, 95% CI: 1.31 to 1.68). In multivariable models conducted among people with lower insomnia severity, later timing, lower rhythmicity, and higher insomnia severity were independent correlates of depression. In people with higher insomnia symptom severity, measures of later timing were most strongly associated with depression symptoms. CONCLUSIONS: These correlative observations suggest that experimental studies are warranted to test if: broadly promoting 24-hour sleep-wake functioning reduces depression even in people without severe insomnia, and if advancing timing leads to depression symptom reductions in people with insomnia.

Sleep and circadian rhythm disruptions in behavioral variant frontotemporal dementia.

INTRODUCTION: Sleep and rest-activity rhythm alterations are common in neurodegenerative diseases. However, their characterization in patients with behavioral variant frontotemporal dementia (bvFTD) has proven elusive. We investigated rest-activity rhythm alterations, sleep disturbances, and their neural correlates in bvFTD. METHODS: Twenty-seven bvFTD patients and 25 healthy controls completed sleep questionnaires and underwent 7 days of actigraphy while concurrently maintaining a sleep diary. Cortical complexity and thickness were calculated from T1-weighted magnetic resonance (MR) images. RESULTS: Compared to controls, bvFTD patients showed longer time in bed (95% confidence interval [CI]: 79.31, 321.83) and total sleep time (95% CI: 24.38, 321.88), lower sleep efficiency (95% CI: -12.58, -95.54), and rest-activity rhythm alterations in the morning and early afternoon. Increased sleep duration was associated with reduced cortical thickness in frontal regions. DISCUSSION: Patients with bvFTD showed longer sleep duration, lower sleep quality, and rest-activity rhythm alterations. Actigraphy could serve as a cost-effective and accessible tool for ecologically monitoring changes in sleep duration in bvFTD patients. HIGHLIGHTS: We assessed sleep and circadian rhythms in behavioral variant frontotemporal dementia (bvFTD) using actigraphy. Patients with bvFTD show increased sleep duration and reduced sleep quality. Patients with bvFTD show rest-activity alterations in the morning and early afternoon. Sleep duration is associated with reduced cortical thickness in frontal regions. These alterations may represent an early sign of neurodegeneration.

Efficacy of the Transdiagnostic Intervention for Sleep and Circadian Dysfunction for Depression Symptoms and Sleep-Wake Disruption in Older and Younger Adults: Secondary Age-Stratified Analysis of a Randomized Controlled Trial.

OBJECTIVE: Perform a secondary analysis examining the efficacy of the Transdiagnostic Intervention for Sleep and Circadian Dysfunction (TranS-C) for depression symptom responses, and explore changes in potential target mechanisms. DESIGN: Secondary analysis of a randomized controlled trial with convenience age subsamples (younger (20-49 year; n = 52) versus and older (50-71 years; n = 35)). SETTING: Community mental health clinics. PARTICIPANTS: Eighty-seven adults with serious mental illness. INTERVENTION: TranS-C versus treatment as usual (TAU). MEASUREMENTS: Outcomes were depression symptoms (Quick Inventory of Depression Symptoms), insomnia symptoms (Insomnia Severity Index), and objective sleep-wake rhythm measures (interdaily stability and relative amplitude). RESULTS: Depression response rates (≥50% symptom reductions) were higher in the TranS-C (35.0%) than the TAU (8.8%) group 6-months postintervention (χ2 = 10.3, p = 0.001). There was a medium effect of TranS-C versus TAU on depression symptoms 6-months postintervention (Cohen's d = -0.40, 95% confidence interval (CI): -0.81, 0.01). In both age groups, there were large treatment effects on insomnia symptoms post-treatment (Cohen's d >0.90). In the older subsample, there were additionally medium treatment effects on post-treatment interdaily stability (Cohen's d = 0.60, 95% CI: -0.11, 1.61). Post-treatment reductions in insomnia symptoms correlated with depression symptom reduction 6-months later in the younger subsample (Spearman rho = 0.59, n = 20, p = 0.008). In older adults, postintervention increases in interdaily stability correlated with depression symptom reductions 6-months later (Spearman rho = -0.52, n = 15, p = 0.049). CONCLUSION: Confirmatory trials are needed, given the low age-specific sample sizes here, to determine if TranS -C's produces durable depression responses by increasing sleep-wake rhythm stability in older adults and improving insomnia symptoms in younger adults. BRIEF ARTICLE SUMMARY: The authors evaluated preliminary efficacy of a behavioral intervention that targets sleep/sleep-wake rhythms, the Transdiagnostic Intervention for Sleep and Circadian Dysfunction (TranS-C), for depression symptoms in people with serious mental illness. TranS-C was associated with higher depression response rates than treatment as usual 6-months postintervention. The degree of depression symptom response 6-months later was related to the degree of treatment phase improvements in interdaily stability (in older adults) and reduction in insomnia severity (in younger adults). A pragmatic nonpharmacologic intervention, the Transdiagnostic Intervention for Sleep and Circadian Dysfunction, has preliminary efficacy for improving sleep-wake factors and depression symptoms.

Effect of Personalized Blue-Enriched White Light Intervention on Rest-Activity and Light Exposure Rhythms in Mild and Moderate Alzheimer's Disease.

OBJECTIVE: We aimed to examine the effectiveness of personalized light intervention using a blue-enriched light-emitting-diodes device on rest-activity rhythm (RAR) and light exposure rhythm (LER) in patients with mild and moderate Alzheimer's disease (AD). METHODS: AD patients with poor sleep quality and/or insomnia symptoms were assigned into either an experimental group (EG) or control group (CG) in a single-blind design. Personalized light intervention was given at 9-10 h after individual dim light melatonin onset, lasting for 1 h every day for two weeks in the EG (77.36±5.79 years, n=14) and CG (78.10±7.98 years, n=10). Each patient of CG wore blue-attenuating sunglasses during the intervention. Actigraphy recording at home for 5 days was done at baseline (T0), immediate postintervention (T1), and at four weeks after intervention (T2). The variables of RAR and LER were derived using nonparametric analysis. RESULTS: We found a significant time effect on the intradaily variability (IV) of RAR at T2 with respect to T0 (p=0.039), indicating reduced IV of RAR at four weeks after personalized light intervention regardless of blue-enriched light intervention. There was a time effect on the IV of LER at T1 with respect to T0 (p=0.052), indicating a reduced tendency in the IV of LER immediately after intervention. CONCLUSION: Our personalized light intervention, regardless of blue-enriched light source, could be useful in alleviating fragmentation of RAR and LER in AD patients.

Characteristics of 24-hour movement behaviours and their associations with mental health in children and adolescents.

Background: Time-use estimates are typically used to describe 24-hour movement behaviours. However, these behaviours can additionally be characterised by other easily measured metrics. These include sleep quality (e.g., sleep efficiency), 24-hour rest-activity rhythmicity (e.g., between-day rhythm variability), and directly measured acceleration metrics (e.g., intensity gradient). Associations between these characteristics and youth mental health are unclear. This study aimed to [1] compare 24-hour movement behaviour characteristics by sex and age groups, [2] determine which movement behaviour characteristics were most strongly associated with mental health outcomes, and [3] investigate the optimal time-use behaviour compositions for different mental health outcomes. Methods: Three-hundred-and-one children and adolescents (age 9-13 y; 60% girls) wore accelerometers for 24-hours/day over 7-days. Overall mental health, externalising, and internalising problems were self-reported using the Strengths and Difficulties Questionnaire. 24-hour movement behaviour characteristics were categorised as time-use estimates, sleep quality, 24-hour activity rhythmicity, and directly measured acceleration. Linear mixed models and compositional data analysis were used to analyse the data in alignment with the study aims. Results: Time-use estimates, directly measured accelerations, and 24-hour rest-activity rhythm metrics indicated that children were significantly more physically active (p = .01-<0.001) than adolescents. Children were also less sedentary (p < .01), slept longer (p = .02-0.01), and had lower sleep efficiency. Boys were significantly more active than girls (p < .001) who in turn accrued more time in sleep (p = .02). The timing of peak activity was significantly later among adolescents (p = .047). Overall mental health and externalising problems were significantly associated with sleep, sedentary time, sleep efficiency, amplitude, and inter-daily stability (p = .04-0.01). The optimal time-use compositions were specific to overall mental health and externalising problems and were characterised by more sleep, light and vigorous physical activity, and less sedentary time and moderate physical activity than the sample's mean time-use composition. Conclusions: Extracting and examining multiple movement behaviour characteristics from 24-hour accelerometer data can provide a more rounded picture of the interplay between different elements of movement behaviours and their relationships with mental health than single characteristics alone, such as time-use estimates. Applying multiple movement behaviour characteristics to the translation of research findings may enhance the impact of the data for research users. Supplementary Information: The online version contains supplementary material available at 10.1186/s44167-023-00021-9.

The relationship between apathy and nonparametric variables of rest activity rhythm in older adults with cerebral small vessel disease.

The goal of the current study was to demonstrate if the rest-activity rhythm (RAR) was altered in apathetic older adults with cerebral small vessel disease (CSVD) and find out the relationship between apathy/depression severity and RAR features in CSVD patients. This is a cross-sectional observational investigation including 53 CSVD cases (54.74% men), aged 70.70 ± 6.18 years old. The participants were assessed by neuropsychiatric inventory (NPI) subscale of apathy (NPI-apathy) and depression (NPI-depression) in succession, according to updated diagnostic criteria for apathy (DCA). Each subject wore an actigraph device (ActiGraph GT3X) in their nondominant hand for 7 days to collect raw data. Using a non-parametric methodological analysis, this study determined RAR variables such as interdaily stability (IS), intraday variability (IV) and relative amplitude (RA). Patients in the apathy-positive group had a higher Fazekas score than those in the apathy-negative group. IS, but not IV, RA, or objective sleep variables, differed between elderly patients with varying degrees of CSVD burden. Furthermore, apathy severity was statistically correlated with RA after adjusting for age, gender and education level, whereas depression severity was not associated with RAR variables. Finally, we discovered that the severity of apathy had no significant relationship with the severity of depression. All these findings indicated that the RAR altered in apathetic older adults with CSVD, and apathy was associated with decreased RAR amplitude.

Association between Acute Respiratory Distress Syndrome Due to COVID-19 and Long-Term Sleep and Circadian Sleep-Wake Disorders.

Current studies agree on the impact of sleep and circadian rest-activity rhythm alterations in acute respiratory distress syndrome (ARDS) survivors. However, research on the duration of this impact is scarce. In this study, we evaluate the impact of ARDS on the sleep and circadian rest-activity rhythm of COVID-19 survivors twelve months after hospital discharge. This is a prospective study including COVID-19 survivors with and without ARDS during hospitalization. Data was collected four and twelve months after hospital discharge. The interventions included one-week wrist actigraphy and a home sleep apnea test (HSAT), and evaluations were conducted according to the Pittsburgh sleep quality index (PSQI), Epworth sleepiness scale (ESS), and insomnia severity index (ISI). Fifty-two patients were evaluated (ARDS = 31 and non-ARDS = 21); they had a median age of 49.0 [39.0;57.2] years and 53.8% were male. After twelve months, 91.3% presented poor sleep quality, 58.7% presented insomnia, 50% presented daytime somnolence, and 37% presented comorbid insomnia and obstructive sleep apnea (COMISA). No significant improvement was observed in relation to sleep or the circadian rest-activity rhythm between four and twelve months. A tendency of poor sleep quality, insomnia, daytime somnolence, and COMISA was observed. Finally, there was no significant impact on the circadian rest-activity rhythm between four and twelve months or between the groups.

U.S. Adolescent Rest-Activity patterns: insights from functional principal component analysis (NHANES 2011-2014).

BACKGROUND: Suboptimal rest-activity patterns in adolescence are associated with worse health outcomes in adulthood. Understanding sociodemographic factors associated with rest-activity rhythms may help identify subgroups who may benefit from interventions. This study aimed to investigate the association of rest-activity rhythm with demographic and socioeconomic characteristics in adolescents. METHODS: Using cross-sectional data from the nationally representative National Health and Nutrition Examination Survey (NHANES) 2011-2014 adolescents (N = 1814), this study derived rest-activity profiles from 7-day 24-hour accelerometer data using functional principal component analysis. Multiple linear regression was used to assess the association between participant characteristics and rest-activity profiles. Weekday and weekend specific analyses were performed in addition to the overall analysis. RESULTS: Four rest-activity rhythm profiles were identified, which explained a total of 82.7% of variance in the study sample, including (1) High amplitude profile; (2) Early activity window profile; (3) Early activity peak profile; and (4) Prolonged activity/reduced rest window profile. The rest-activity profiles were associated with subgroups of age, sex, race/ethnicity, and household income. On average, older age was associated with a lower value for the high amplitude and early activity window profiles, but a higher value for the early activity peak and prolonged activity/reduced rest window profiles. Compared to boys, girls had a higher value for the prolonged activity/reduced rest window profiles. When compared to Non-Hispanic White adolescents, Asian showed a lower value for the high amplitude profile, Mexican American group showed a higher value for the early activity window profile, and the Non-Hispanic Black group showed a higher value for the prolonged activity/reduced rest window profiles. Adolescents reported the lowest household income had the lowest average value for the early activity window profile. CONCLUSIONS: This study characterized main rest-activity profiles among the US adolescents, and demonstrated that demographic and socioeconomic status factors may shape rest-activity behaviors in this population.

The rest-activity rhythm, genetic susceptibility and risk of type 2 diabetes: A prospective study in UK Biobank.

AIMS: This study aims to examine the association between the rest-activity rhythm (RAR) and the incidence of type 2 diabetes (T2D). MATERIALS AND METHODS: In total, 97 503 participants without diabetes in the UK Biobank cohort were recruited. Wearable accelerometry was used to monitor circadian behaviour. The parameters of RAR including inter-daily stability, intra-daily variability, relative amplitude (RA), most active continuous 10 h period (M10), and least active continuous 5 h period (L5) were calculated to evaluate the robustness and regularity of the RAR. The weighted polygenic risk score for T2D (T2D-PRS) was calculated. Cox proportion hazards models were used to evaluate the survival relationship and the joint and interaction effects of RAR parameters and T2D-PRS on the occurrence of T2D. RESULTS: During 692 257 person-years follow-ups, a total of 2434 participants were documented. After adjustment for potential confounders, compared with participants in the highest quartile of RA and M10, the participants in the lowest quartile had a greater risk of T2D (HRRA = 2.06, 95% CI: 1.76-2.41; HRM10 = 1.33, 95% CI: 1.19-1.49). Meanwhile, the highest quartile of L5 was related to a higher risk of T2D (HR = 1.78, 95% CI: 1.55-2.24). The joint analysis showed that the high T2D-PRS with the lowest quartile of RA and M10, or highest quartile of L5 jointly increased the risk of T2D (HRRA = 4.46, 95% CI: 3.36-6.42; HRM10 = 3.15, 95% CI: 2.29-4.32; HRL5 = 3.09, 95% CI: 2.40-3.99). No modification effects of T2D-PRS on the association between the RAR parameters and risk of T2D were observed (p > .05). CONCLUSION: The unbalanced RAR are associated with a greater risk of T2D, which are independent of known risk factors of T2D.

Rest-Activity Rhythm, Pain, and Motor Activity in Multiple Sclerosis.

BACKGROUND: Although the relationships among physical disability, mood disorders, and pain are well described in multiple sclerosis (MS), little is known about whether those symptoms are associated with sleep disturbances. METHODS: Forty-six patients with MS experiencing pain participated. Sleep was indirectly measured by assessing rest-activity rhythm via actigraphy: interdaily stability, intradaily variability, and relative amplitude. Pain was assessed using visual and verbal analog scales, mood by the Beck Depression Inventory and Symptom Checklist-90, and physical disability by the Expanded Disability Status Scale. RESULTS: Incorporating mood, pain, and physical disability into 1 regression model resulted in a significant association with interdaily stability. CONCLUSIONS: Compared with intradaily variability and relative amplitude, interdaily stability seems to be the most vulnerable actigraphy variable for mood disturbances, pain, and physical disabilities.

Six multidimensional sleep health facets in older adults identified with factor analysis of actigraphy: Results from the Einstein Aging Study.

OBJECTIVES: The concept of multi-dimensional sleep health, originally based on self-report, was recently extended to actigraphy in older adults, yielding five components, but without a hypothesized rhythmicity factor. The current study extends prior work using a sample of older adults with a longer period of actigraphy follow-up, which may facilitate observation of the rhythmicity factor. METHODS: Wrist actigraphy measures of participants (N = 289, Mage = 77.2 years, 67% females; 47% White, 40% Black, 13% Hispanic/Others) over 2 weeks were used in exploratory factor analysis to determine factor structures, followed by confirmatory factor analysis on a different subsample. The utility of this approach was demonstrated by associations with global cognitive performance (Montreal Cognitive Assessment). RESULTS: Exploratory factor analysis identified six factors: Regularity: standard deviations of four sleep measures: midpoint, sleep onset time, night total sleep time (TST), and 24-hour TST; Alertness/Sleepiness (daytime): amplitude, napping (mins and #/day); Timing: sleep onset, midpoint, wake-time (of nighttime sleep); up-mesor, acrophase, down-mesor; Efficiency: sleep maintenance efficiency, wake after sleep onset; Duration: night rest interval(s), night TST, 24-hour rest interval(s), 24-hour TST; Rhythmicity (pattern across days): mesor, alpha, and minimum. Greater sleep efficiency was associated with better Montreal Cognitive Assessment performance (ß [95% confidence interval] = 0.63 [0.19, 1.08]). CONCLUSIONS: Actigraphic records over 2 weeks revealed that Rhythmicity may be an independent factor in sleep health. Facets of sleep health can facilitate dimension reduction, be considered predictors of health outcomes, and be potential targets for sleep interventions.

Association between rest-activity rhythm and cognitive function in the elderly: The U.S. National Health and Nutrition Examination Survey, 2011-2014.

Background: Circadian rhythm plays an essential role in various physiological and pathological processes related to cognitive function. The rest-activity rhythm (RAR) is one of the most prominent outputs of the circadian system. However, little is known about the relationships between RAR and different domains of cognitive function in older adults. The purpose of this study was to examine the relationships between RAR and various fields of cognitive function in older Americans. Methods: This study included a total of 2090 older adults ≥ 60 years old from the National Health and Nutrition Examination Survey (NHANES) in 2011-2014. RAR parameters were derived from accelerometer recordings. Cognitive function was assessed using the word learning subtest developed by the Consortium to Establish a Registry for Alzheimer's disease (CERAD W-L), the Animal Fluency Test (AFT) and the Digital Symbol Substitution Test (DSST). Linear regression was used to determine the relationships between RAR parameters (IS, IV, RA, L5, M10) and cognitive function scores (CERAD W-L, AFT, DSST). Results: After adjusting for potential confounders, lower IS and M10 were associated with lower CERAD W-L scores (P=0.033 and P=0.002, respectively). Weaker RA and higher L5 were associated with lower AFT scores (P<0.001 and P=0.001, respectively). And lower IS, RA, and higher L5 were associated with lower DSST scores (P=0.019, P<0.001 and P<0.001, respectively). In addition, the results of sensitivity analysis were similar to those of our main analyses. The main correlation results between the RAR indicators and cognitive function were robust. Conclusions: This study suggested that the weakened and/or disrupted RAR was associated with cognitive decline in different domains in Americans over the age of 60.

The evolving role of quantitative actigraphy in clinical sleep medicine.

Actigraphy has a consolidated role in Insomnia and Circadian Rhythm Sleep-Wake Disorders (CRSWD) and recent studies have highlighted the use of actigraphy for narcolepsy and REM sleep behaviour disorder (RBD). This review aims at summarising the results of studies published over the last decade regarding the use of actigraphy. Thirty-five studies proved eligible, and results were analysed separately for insomnia, narcolepsy and RBD. Actigraphy showed to consistently differentiate insomnia patients from healthy controls. Furthermore, the application of advanced analytical techniques has been shown to provide both unique insights into the physiology of insomnia and sleep misperception and to improve the specificity of actigraphy in detecting wakefulness within sleep periods. Regarding narcolepsy, several studies showed that actigraphy can detect peculiar sleep/wake disruption and the effects of pharmacological treatments. Finally, although the number of studies in RBD patients is still limited, the available evidence indicates a reduced amplitude of the activity pattern, sleep-wake rhythm dysregulation and daytime sleepiness. Therefore, the potential use of these markers as predictors of phenoconversion should be further explored. In conclusion, quantitative actigraphy presents a renewed interest when considering the possibility of using actigraphy in clinical sleep medicine to diagnose, monitor, and follow sleep disorders other than CRSWD.

Circadian rest-activity rhythm and longitudinal brain changes underlying late-life cognitive decline.

AIM: The neurobiological substrates underlying the relationship of circadian rest-activity rhythm (RAR) alteration with accelerated late-life cognitive decline are not clearly understood. In the present study, the longitudinal relationship of objectively measured circadian RAR with in vivo Alzheimer disease (AD) pathologies and cerebrovascular injury was investigated in older adults without dementia. METHODS: The present study included 129 participants without dementia who participated in the KBASE (Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer's Disease) cohort. All participants underwent actigraphy at baseline and two consecutive [11 C] Pittsburgh compound-B positron emission tomography (PET), [18 F] fluorodeoxyglucose-PET, magnetic resonance imaging, and Mini-Mental State Examination (MMSE) at baseline and at a 2-year follow-up assessment. The associations of circadian RAR with annualized change in neuroimaging measures including global amyloid-beta retention, AD-signature region cerebral glucose metabolism (AD-CM), and white matter hyperintensity volume were examined. RESULTS: Delayed acrophase at baseline was significantly associated with greater annualized decline of AD-CM over a 2-year period, but not with that of other neuroimaging measures. In contrast, other circadian RAR parameters at baseline had no association with annualized change of any neuroimaging measures. Annualized decline of AD-CM was also significantly positively associated with the annual change in MMSE scores. Furthermore, a mediation analysis showed that greater reduction in AD-CM mediated the effect of delayed acrophase at baseline on faster decline of MMSE score. CONCLUSION: The findings indicate that delayed acrophase in late life may cause or predict hypometabolism at AD-signature brain regions, which underlies cognitive decline in the near future.