Variation in actigraphy-estimated rest-activity patterns by demographic factors

Sex Differences in the Association Between 24-hour Rest-Activity Rhythms and Frailty Among U.S. Older Adults: Findings From NHANES 2011-2014

BACKGROUND

Little is known as to how rest-activity rhythms are associated with frailty and how this relationship differs by sex. This study examined the relationship between rest-activity rhythms and frailty in a nationally representative sample of U.S. older adults, focusing on the moderating role of sex.

METHODS

2 531 participants aged ≥60 years (females: 55.2%; frail: 5.15% [4.02-6.29]; pre-frail: 33.49% [31.29-35.68]) were included using the 2011-2014 National Health and Nutrition Examination Survey. Nonparametric rest-activity rhythms parameters, including inter-daily stability, intra-daily variability, relative amplitude, most active 10-hour, and least active 5-hour, were estimated from wrist-worn actigraphy data. Frailty status was assessed using a modified version of frailty phenotype (range: 0-5): frail (≥3), pre-frail (1,2), and non-frail (0). Multinomial logistic regression models were used to examine the interest of associations, adjusting for potential confounders.

RESULTS

Frail and pre-frail older adults exhibited significantly lower relative amplitude, inter-daily stability, higher intra-daily variability, and phase delay when compared with non-frail older adults (p's < .05). Particularly, older adults with low relative amplitude had significantly greater odds of being frail and pre-frail (aOR [95% confidence intervals]; frailty: 5.60 [2.61-12.04]; pre-frailty: 1.58 [1.13-2.20]). Significant sex-interaction was observed (p < .01), with this association being greater in females than in males (aOR [95% confidence intervals]; females: 7.78 [2.98-20.30] for frailty, 2.31 [1.60-3.32] for pre-frailty; males: 4.48 [1.38-14.54] for frailty, 1.12 [0.61-2.07] for pre-frailty).

CONCLUSION

Weakened rest-activity rhythms strength is unfavorably associated with frailty, particularly in females. Rest-activity rhythms may be a useful indicator associated with frailty in older adults, but sex-specific differences should be considered. Further longitudinal research is necessary to investigate the bidirectionality of their association.

The effects of COVID-19 lockdown and reopening on rest-activity rhythms in Singaporean working adults: A longitudinal age group comparison study

STUDY OBJECTIVES

COVID-19 mobility restrictions disrupted daily rhythms worldwide, but how this rhythm disruption differs across age groups is unclear. We examined the course of age-related differences in trajectories of rest-activity rhythm during the COVID-19 pandemic lockdown and reopening in Singapore. We also evaluated the association of these patterns with mental well-being.

METHODS

24-hour step count data (Fitbit) were obtained from 617 younger (age range: 21-40) and 602 older adults (age range: 55-70) from January 2020 (baseline) through lockdown (April 2020) and reopening periods until August 2021. Nonparametric rest-activity rhythm metrics: interdaily stability, intradaily variability and most active 10-hour period (M10) were computed. Longitudinal changes in rest-activity rhythm, age-related differences in changes, and the associations between mental well-being and these changes were assessed using nonlinear latent-growth models.

RESULTS

In younger adults, mobility restrictions during lockdown caused significant decline in interdaily stability and M10, alongside significant increase in intradaily variability. However, in older adults, changes were confined to increased intradaily variability and decreased M10. Older adults also showed less change in intradaily variability and M10 compared to younger adults. Gradual recovery of rest-activity rhythm metrics during reopening was observed, with interdaily stability and M10 remaining lower after 15months post-lockdown. In younger but not older adults, a larger decline in interdaily stability was associated with poorer mental well-being 15months post-lockdown.

CONCLUSION

Younger adults appear more vulnerable than older adults to mobility restrictions as reflected in their rest-activity rhythm metrics. A significant disruption of daily routine may have long-lasting effects on younger adults' mental well-being.

STATEMENT OF SIGNIFICANCE

Although stringent mobility restrictions imposed to curb the spread of COVID-19 were imposed primarily to protect older adults, we found that younger adults were more vulnerable to rhythm disruption arising from mobility restrictions. Disrupted rhythm stability was associated with poorer mental well-being 15months after the lockdown ended in younger but not older adults. These asymmetric long-term effects on mental health on younger relative to older adults should be kept in mind when planning for large-scale catastrophes linked to mobility restrictions.

Wearables in Chronomedicine and Interpretation of Circadian Health

Wearable devices have gained increasing attention for use in multifunctional applications related to health monitoring, particularly in research of the circadian rhythms of cognitive functions and metabolic processes. In this comprehensive review, we encompass how wearables can be used to study circadian rhythms in health and disease. We highlight the importance of these rhythms as markers of health and well-being and as potential predictors for health outcomes. We focus on the use of wearable technologies in sleep research, circadian medicine, and chronomedicine beyond the circadian domain and emphasize actigraphy as a validated tool for monitoring sleep, activity, and light exposure. We discuss various mathematical methods currently used to analyze actigraphic data, such as parametric and non-parametric approaches, linear, non-linear, and neural network-based methods applied to quantify circadian and non-circadian variability. We also introduce novel actigraphy-derived markers, which can be used as personalized proxies of health status, assisting in discriminating between health and disease, offering insights into neurobehavioral and metabolic status. We discuss how lifestyle factors such as physical activity and light exposure can modulate brain functions and metabolic health. We emphasize the importance of establishing reference standards for actigraphic measures to further refine data interpretation and improve clinical and research outcomes. The review calls for further research to refine existing tools and methods, deepen our understanding of circadian health, and develop personalized healthcare strategies.

Cross-sectional relationships of circadian misalignment and rest-activity rhythms with occupational attainment in UK Biobank participants

Circadian misalignment and disrupted rest-activity rhythms have been linked to adverse health and educational outcomes, yet few studies have considered their relationships with economic outcomes. We investigate associations between multiple accelerometer-measured circadian misalignment traits (Composite Phase Deviation and the Sleep Regularity Index) and rest-activity rhythm traits (Inter-daily Stability, Intra-daily variability and relative amplitude), with occupational attainment, measured using the average wage paid to an individual's occupation. We use data from 20 356 UK Biobank participants who wore an accelerometer (2013-16), provided employment data for the year they wore the accelerometer, and supplied covariate data at recruitment (2006-10). We use linear regression, with incremental adjustments for four sets of covariates, and stratify our analysis by sex. Our findings provide mixed evidence on the relationship between circadian misalignment and occupational attainment, varying by the measure of circadian misalignment used, and sex. We find fragmented rest-activity rhythms to be associated with higher occupational attainment, which is counterintuitive. Since circadian misalignment is a modifiable trait, our results suggest potential benefits of policies aimed at reducing circadian misalignment, such as altering work schedules and reducing bright light exposure in the evening. Further research is needed to elucidate the mechanisms through which rest-activity rhythms may impact economic outcomes.

Sleep fragmentation despite intact rest-activity patterns in premanifest Huntington's disease: An actigraphy study

OBJECTIVE

Sleep research in Huntington's disease (HD) has primarily focused on manifest HD, with significantly less attention given to premanifest HD (Pre-HD). Therefore, we investigated sleep and rest-activity patterns in people with Pre-HD versus healthy controls (HC).

METHODS

We conducted a cross-sectional study including 36 Pre-HD and 48 HC participants. Pre-HD participants were stratified into three groups according to their proximity to estimated diagnosis, using a cytosine-adenine-guanine (CAG) and current age-based predictive model: NEAR (<9 years to diagnosis), MID (9-15 years to diagnosis) and FAR (>15 years to diagnosis). Sleep and rest-activity patterns were assessed using wrist-worn actigraphy, a sleep diary, and sleep questionnaires.

RESULTS

NEAR and MID groups experienced higher fragmentation index than HC and FAR groups. NEAR and MID groups also exhibited greater WASO than the FAR group. NEAR and MID groups showed lower intra-daily variability (IV) than HC and FAR groups, with the NEAR group also being more active in the most active 10 h (M10). Groups did not differ on subjective sleep measures, inter-daily stability (IS), sleep regularity index, relative amplitude, or amount of activity in the least active 5 h (L5). Considering all Pre-HD participants, fewer years to diagnosis, higher CAG-age-product (CAP) scores (a measure of cumulative exposure to the HD-causing gene mutation) and larger CAG repeat lengths correlated with higher WASO, fragmentation index, L5, IS, and lower sleep efficiency and IV. Higher CAP score correlated with higher M10.

CONCLUSIONS

Despite intact rest-activity patterns and similar subjective sleep quality to HC, greater sleep fragmentation is a prominent and early feature in Pre-HD. Therefore, reducing sleep fragmentation may be a potential target for sleep intervention in HD. Longitudinal studies using larger samples are needed to assess sleep across the disease spectrum and its impact on clinical outcomes, like cognition.

Multidimensional Sleep Health in Surrogate Decision-Makers of Critically Ill Patients

BACKGROUND

Supporting the sleep health of surrogate decision-makers of patients in the intensive care unit is a research priority. However, few studies have approached sleep health as a multidimensional construct, instead focusing on 1 or 2 dimensions in isolation.

OBJECTIVE

To holistically examine the sleep health (satisfaction, timing, efficiency, duration) of surrogate decision-makers of critically ill patients.

METHODS

This secondary analysis involved surrogate decision-makers of incapacitated intensive care unit patients at a tertiary medical center in northeastern Ohio (n = 19). Sleep-health data were captured by means of a subjective scale (satisfaction) and objectively (timing, efficiency, duration) by means of a wrist-worn accelerometer (Actiwatch Spectrum Plus; Philips Respironics). Upon enrollment, participants completed the satisfaction scale and wore the Actiwatch Spectrum Plus for 3 consecutive days. Descriptive statistics of the study variables were evaluated.

RESULTS

A minority (15%) of the sample reported poor sleep satisfaction. Sleep timing variables were comparable to those found in other adult studies. Participants averaged approximately 6 hours of sleep per day with an average sleep efficiency of 83.7%.

CONCLUSIONS

Despite adequate satisfaction scores, intensive care unit surrogate decision-makers' sleep duration is inadequate and sleep efficiency is suboptimal. Sleep-health interventions may be needed in this at-risk population. Future research should consider the impact of surrogate decision-maker sleep health on their capacity to serve in the surrogate decision-maker role.

The lifestyle of new middle-aged and older adults in Taiwan described by wearable device: age and gender differences

Studies of lifestyle through comprehensive objective and subjective measurements of health outcomes are lacking. An examination of lifestyle factors in middle-aged and older adults in terms of age, gender, and the interaction effect of age and gender from physiological and psychological perspectives are imperative. Recent advances in technology such as actigraphy have facilitated objective measurements. This exploratory study contributes to research on age and gender interactions on circadian rhythm, physical activity, sleep, and psychological variables by employing wrist accelerometers to measure behavioral circadian rhythm objectively and by using questionnaires to assess psychological status subjectively. The data were drawn from 218 participants aged 50 and older from the "Middle-aged and older adults Chinese Health and Actigraphy in Taiwan (MOCHA-T)". The results: (1) older adult group is associated with declined physical activity (MVPA time 79.9 min VS. 107.9 min, p = .002), worse sleep efficiency (78.1% VS. 81.9%, p = .008), and earlier lifestyle (Acrophase 14.19 h VS. 14.69 h, p = .01) comparing to middle-aged group. (2) Women have a more regular lifestyle (Interdaily stability 0.6 VS. 051, p < 0.001), higher physical activity (MVPA time 105.7 min VS. 79.3 min, p = .004), and better sleep efficiency (81.6% VS. 77.8%, p = .011) than men. (3) Significant age-by-gender interactions existed in life satisfaction (p = .025), relative amplitude (p = .016), and total wake time (p = .038). Furthermore, aging was associated with significant increases in life satisfaction among men as well as significant decreases in relative amplitude and reductions in the total wake time among women. In conclusion, aging exerted differential effects on life satisfaction in men as well as relative amplitude and the total wake time in women. This result highlights disparities in lifestyle arising from interconnected social and biological challenges.

How many days are enough? Sleep-wake timing regularity and fragmentation scores change with the number of days included

The duration of sleep data collection from actigraphy is often influenced by practical factors (e.g. workdays versus non-workdays), but the impact of the variation of duration on outcome measures of interest has not been well explored. This study investigates the effect of the duration of actigraphy measurement on non-parametric measures of 24-hr sleep-wake rhythms. We examined regularity inter-daily stability and fragmentation intra-daily variation over 14 days or the first 7 days in participants (n = 41) undergoing evaluation for sleep disorders. Bland-Altman plots assessed the impact of fewer than 14 or 7 days, respectively, on inter-daily stability and intra-daily variation scores. Intra-daily variation values were also calculated for each day and compared with the 14-day intra-daily variation. Compared with the entire 14-day period, using shorter durations (< 7 days) led to a higher estimated bias and increased variance in the limits of agreement for inter-daily stability. Intra-daily variation values showed increased variation in the limits of agreement with fewer days. Similar trends were observed when comparing shorter actigraphy periods 3 or 5 days-7 days. Daily intra-daily variation calculations indicate that individuals with higher daily fragmentation experienced more pronounced day-to-day fragmentation and greater variability in the degree of fragmentation, in a linear association between daily intra-daily variation standard deviation and 14-day intra-daily variation values. Our data indicate that a minimum of 7 full days of actigraphy is recommended to reduce measurement errors, and intra-daily variation and inter-daily stability derived from less than 7 days cannot be compared with those from more than 7 days without significant error.

Associations between Aircraft Noise, Sleep, and Sleep-Wake Cycle: Actimetric Data from the UK Biobank Cohort near Four Major Airports

BACKGROUND

Nighttime aircraft noise may affect people's sleep, yet large-scale evidence using objective and subjective measures remains limited.

OBJECTIVE

Our aim was to investigate associations between nighttime aircraft noise exposure and objectively measured sleep disturbance using a large UK cohort.

METHODS

We used data from 105,770 UK Biobank cohort participants exposed and unexposed to aircraft noise who lived in 44 local authority districts near 4 international airports in England. We used a generalized linear regression model to examine cross-sectional associations between aircraft noise L night (23:00 hours-07:00 hours) and 7-d actimetric measures collected 2013-2015 (n = 22,102 ). We also used Logit and generalized estimating equations models to examine associations between L night and self-reported sleep measures at enrollment (2006-2010) and follow-up (2012-2013). This approach allowed us to compare and contrast the results and support potential future meta-analyses on noise-related sleep disturbance.

RESULTS

Cross-sectional analyses of actimetric data suggested sleep disturbance associated with L night , showing higher level of movements during the least active continuous 8-h time period [β : 0.12 milligravitational units; 95% confidence interval (CI): 0.013, 0.23]. We also saw disrupted sleep-wake cycles as indicated by index scores of lower relative amplitude (β : - 0.006 ; 95% CI: - 0.007 , - 0.005 ), poorer interdaily stability (β : - 0.010 ; 95% CI: - 0.014 , - 0.006 ), and greater intradaily variability (β : 0.021; 95% CI: 0.019, 0.023), comparing L night ≥ 55 dB with < 45 dB. Repeated cross-sectional analyses found a 52% higher odds of more frequent daytime dozing [odds ratio (OR) = 1.52 ; 95% CI: 1.32, 1.75] for L night ≥ 55 dB in comparison with < 45 dB, whereas the likelihood for more frequent sleeplessness was more uncertain (OR = 1.13 ; 95% CI: 0.92, 1.39). Higher effect sizes were seen in preidentified vulnerable groups, including individuals > 65 y of age and those with diabetes or dementia.

CONCLUSION

Individuals exposed to higher levels of aircraft noise experienced objectively higher levels of sleep disturbance and changes in sleep-wake cycle. https://doi.org/10.1289/EHP14156.

Comparing Human-Smartphone Interactions and Actigraphy Measurements for Circadian Rhythm Stability and Adiposity: Algorithm Development and Validation Study

BACKGROUND

This study aimed to investigate the relationships between adiposity and circadian rhythm and compare the measurement of circadian rhythm using both actigraphy and a smartphone app that tracks human-smartphone interactions.

OBJECTIVE

We hypothesized that the app-based measurement may provide more comprehensive information, including light-sensitive melatonin secretion and social rhythm, and have stronger correlations with adiposity indicators.

METHODS

We enrolled a total of 78 participants (mean age 41.5, SD 9.9 years; 46/78, 59% women) from both an obesity outpatient clinic and a workplace health promotion program. All participants (n=29 with obesity, n=16 overweight, and n=33 controls) were required to wear a wrist actigraphy device and install the Rhythm app for a minimum of 4 weeks, contributing to a total of 2182 person-days of data collection. The Rhythm app estimates sleep and circadian rhythm indicators by tracking human-smartphone interactions, which correspond to actigraphy. We examined the correlations between adiposity indices and sleep and circadian rhythm indicators, including sleep time, chronotype, and regularity of circadian rhythm, while controlling for physical activity level, age, and gender.

RESULTS

Sleep onset and wake time measurements did not differ significantly between the app and actigraphy; however, wake after sleep onset was longer (13.5, SD 19.5 minutes) with the app, resulting in a longer actigraphy-measured total sleep time (TST) of 20.2 (SD 66.7) minutes. The obesity group had a significantly longer TST with both methods. App-measured circadian rhythm indicators were significantly lower than their actigraphy-measured counterparts. The obesity group had significantly lower interdaily stability (IS) than the control group with both methods. The multivariable-adjusted model revealed a negative correlation between BMI and app-measured IS (P=.007). Body fat percentage (BF%) and visceral adipose tissue area (VAT) showed significant correlations with both app-measured IS and actigraphy-measured IS. The app-measured midpoint of sleep showed a positive correlation with both BF% and VAT. Actigraphy-measured TST exhibited a positive correlation with BMI, VAT, and BF%, while no significant correlation was found between app-measured TST and either BMI, VAT, or BF%.

CONCLUSIONS

Our findings suggest that IS is strongly correlated with various adiposity indicators. Further exploration of the role of circadian rhythm, particularly measured through human-smartphone interactions, in obesity prevention could be warranted.

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.

Investigating Rhythmicity in App Usage to Predict Depressive Symptoms: Protocol for Personalized Framework Development and Validation Through a Countrywide Study

BACKGROUND

Understanding a student's depressive symptoms could facilitate significantly more precise diagnosis and treatment. However, few studies have focused on depressive symptom prediction through unobtrusive systems, and these studies are limited by small sample sizes, low performance, and the requirement for higher resources. In addition, research has not explored whether statistically significant rhythms based on different app usage behavioral markers (eg, app usage sessions) exist that could be useful in finding subtle differences to predict with higher accuracy like the models based on rhythms of physiological data.

OBJECTIVE

The main objective of this study is to explore whether there exist statistically significant rhythms in resource-insensitive app usage behavioral markers and predict depressive symptoms through these marker-based rhythmic features. Another objective of this study is to understand whether there is a potential link between rhythmic features and depressive symptoms.

METHODS

Through a countrywide study, we collected 2952 students' raw app usage behavioral data and responses to the 9 depressive symptoms in the 9-item Patient Health Questionnaire (PHQ-9). The behavioral data were retrieved through our developed app, which was previously used in our pilot studies in Bangladesh on different research problems. To explore whether there is a rhythm based on app usage data, we will conduct a zero-amplitude test. In addition, we will develop a cosinor model for each participant to extract rhythmic parameters (eg, acrophase). In addition, to obtain a comprehensive picture of the rhythms, we will explore nonparametric rhythmic features (eg, interdaily stability). Furthermore, we will conduct regression analysis to understand the association of rhythmic features with depressive symptoms. Finally, we will develop a personalized multitask learning (MTL) framework to predict symptoms through rhythmic features.

RESULTS

After applying inclusion criteria (eg, having app usage data of at least 2 days to explore rhythmicity), we kept the data of 2902 (98.31%) students for analysis, with 24.48 million app usage events, and 7 days' app usage of 2849 (98.17%) students. The students are from all 8 divisions of Bangladesh, both public and private universities (19 different universities and 52 different departments). We are analyzing the data and will publish the findings in a peer-reviewed publication.

CONCLUSIONS

Having an in-depth understanding of app usage rhythms and their connection with depressive symptoms through a countrywide study can significantly help health care professionals and researchers better understand depressed students and may create possibilities for using app usage-based rhythms for intervention. In addition, the MTL framework based on app usage rhythmic features may more accurately predict depressive symptoms due to the rhythms' capability to find subtle differences.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/51540.

Design and Rationale of Prolonged Nightly Fasting for Multiple Myeloma Prevention (PROFAST): Protocol for a Randomized Controlled Pilot Trial

BACKGROUND

Obesity is an established, modifiable risk factor of multiple myeloma (MM); yet, no lifestyle interventions are routinely recommended for patients with overweight or obesity with MM precursor conditions. Prolonged nightly fasting is a simple, practical dietary regimen supported by research, suggesting that the synchronization of feeding-fasting timing with sleep-wake cycles favorably affects metabolic pathways implicated in MM. We describe the design and rationale of a randomized controlled pilot trial evaluating the efficacy of a regular, prolonged nighttime fasting schedule among individuals with overweight or obesity at high risk for developing MM or a related lymphoid malignancy.

OBJECTIVE

We aim to investigate the effects of 4-month prolonged nightly fasting on body composition and tumor biomarkers among individuals with overweight or obesity with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), or smoldering Waldenström macroglobulinemia (SWM).

METHODS

Individuals with MGUS, SMM, or SWM aged ≥18 years and a BMI of ≥25 kg/m2 are randomized to either a 14-hour nighttime fasting intervention or a healthy lifestyle education control group. Participants' baseline diet and lifestyle patterns are characterized through two 24-hour dietary recalls: questionnaires querying demographic, comorbidity, lifestyle, and quality-of-life information; and wrist actigraphy measurements for 7 days. Fasting intervention participants are supported through one-on-one telephone counseling by a health coach and automated SMS text messaging to support fasting goals. Primary end points of body composition, including visceral and subcutaneous fat (by dual-energy x-ray absorptiometry); bone marrow adiposity (by bone marrow histology); and tumor biomarkers, specifically M-proteins and serum free light-chain concentrations (by gel-based and serum free light-chain assays), are assessed at baseline and after the 4-month study period; changes therein from baseline are evaluated using a repeated measures mixed-effects model that accounts for the correlation between baseline and follow-up measures and is generally robust to missing data. Feasibility is assessed as participant retention (percent dropout in each arm) and percentage of days participants achieved a ≥14-hour fast.

RESULTS

The PROlonged nightly FASTing (PROFAST) study was funded in June 2022. Participant recruitment commenced in April 2023. As of July 2023, six participants consented to the study. The study is expected to be completed by April 2024, and data analysis and results are expected to be published in the first quarter of 2025.

CONCLUSIONS

PROFAST serves as an important first step in exploring the premise that prolonged nightly fasting is a strategy to control obesity and obesity-related mechanisms of myelomagenesis. In evaluating the feasibility and impact of prolonged nightly fasting on body composition, bone marrow adipose tissue, and biomarkers of tumor burden, this pilot study may generate hypotheses regarding metabolic mechanisms underlying MM development and ultimately inform clinical and public health strategies for MM prevention.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05565638; http://clinicaltrials.gov/ct2/show/NCT05565638.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/51368.

Associations of social jetlag with physical activity and sedentary behaviour in children and adolescents: A systematic review and meta-analysis

Sleep and daytime movement behaviours occur co-dependently with each other within a finite 24 h day. Sleep parameters other than sleep duration, such as social jetlag and chronotype, have been linked to health problems and unhealthy behaviours among children and adolescents. Given the increasing number of studies examining sleep timing/chronotype and weight-related behaviours, including physical activity and sedentary behaviour, in the past decade, this systematic review and meta-analysis collated and evaluated the evidence on the relationships of social jetlag and chronotype with physical activity and sedentary behaviour among children and adolescents aged 3-17 years. Seven databases were searched on 16 March 2022, and 52 studies were identified as eligible for inclusion, 47 of which were suitable for the meta-analysis. A positive association was found between social jetlag and screen media use (r = 0.14, 95% CI: 0.04-0.24; I2  = 96%; p = 0.008). The morning chronotype was associated with a higher level of physical activity and a lower level of sedentary behaviour than the evening chronotype. No relationship was found between social jetlag and physical activity. The magnitude of heterogeneity among the included studies was high. Further experimental studies are urgently required to understand how circadian preference or misalignment affects activity behaviours. Interventions to promote an active lifestyle in young populations should consider their circadian preference, especially among individuals with the evening chronotype.

Cardiorespiratory fitness and circadian rhythms in adolescents: a pilot study

Although cardiorespiratory fitness (CRF), an important marker of youth health, is associated with earlier sleep/wake schedule, its relationship with circadian rhythms is unclear. This study examined the associations between CRF and rhythm variables in adolescents. Eighteen healthy adolescents (10 females and 8 males; Mage = 14.6 ± 2.3 yr) completed two study visits on weekdays bracketing an ambulatory assessment during summer vacation. Visit 1 included in-laboratory CRF assessment (peak V̇o2) using a ramp-type progressive cycle ergometry protocol and gas exchange measurement, which was followed by 7-14 days of actigraphy to assess sleep/wake patterns and 24-h activity rhythms. During Visit 2, chronotype, social jetlag (i.e., the difference in midsleep time between weekdays and weekends), and phase preference were assessed using a questionnaire, and hourly saliva samples were collected to determine the dim light melatonin onset (DLMO) phase. All analyses were adjusted for sex, pubertal status, and physical activity. Greater peak V̇o2 was associated with earlier sleep/wake times and circadian phase measures, including acrophase, UP time, DOWN time, last activity peak (LAP) time, and chronotype (all P < 0.05). Peak V̇o2 was negatively associated with social jetlag (P = 0.02). In addition, the mixed-model analysis revealed a significant interaction effect between peak V̇o2 and actigraphy-estimated hour-by-hour activity patterns (P < 0.001), with the strongest effects observed at around the time of waking (0600-1000). In healthy adolescents, better CRF was associated with an earlier circadian phase and increased activity levels notably during the morning. Future studies are needed to investigate the longitudinal effects of the interactions between CRF and advanced rhythms on health outcomes.NEW & NOTEWORTHY In healthy adolescents, better cardiorespiratory fitness, as assessed by the gold standard measure [laboratory-based assessment of peak oxygen consumption (V̇o2)], was associated with earlier circadian timing of sleep/wake patterns, rest-activity rhythms and chronotype, and less social jetlag. These findings highlight the close interrelationships between fitness and rhythms and raise the possibility that maintaining higher cardiorespiratory fitness levels alongside earlier sleep/wake schedule and activity rhythms may be important behavioral intervention targets to promote health in adolescents.

The middle-aged and older Chinese adults' health using actigraphy in Taiwan (MOCHA-T): protocol for a multidimensional dataset of health and lifestyle

BACKGROUND AND OBJECTIVES

Older adults keep transforming with Baby Boomers and Gen Xers being the leading older population. Their lifestyle, however, is not well understood. The middle-aged and older Chinese adults' health using actigraphy in Taiwan (MOCHA-T) collected both objective and subjective data to depict the health and lifestyle of this population. The objectives, design, and measures of the MOCHA-T study are introduced, and the caveats and future directions related to the use of the data are presented.

METHODS

People aged 50 and over were recruited from the community, with a subset of women aged 45-49 invited to supplement data on menopause and aging. Four instruments (i.e., self-reported questionnaires, diary, wrist actigraphy recorder, and GPS) were used to collect measures of sociodemographic, health, psychosocial, behavioral, temporal, and spatial data.

RESULTS

A total of 242 participants who returned the informed consent and questionnaires were recruited in the MOCHA-T study. Among them, 94.6%, 95.0%, and 25.2% also completed the diary, actigraphy, and GPS data, respectively. There was almost no difference in sociodemographic characteristics between those with and without a completed diary, actigraphy, and GPS data, except for age group and educational level for those who returned completed actigraphy data.

CONCLUSION

The MOCHA-T study is a multidimensional dataset that allows researchers to describe the health, behaviors, and lifestyle patterns, and their interactions with the environment of the newer generation of middle-aged and older adults in Taiwan. It can be compared with other countries with actigraphy and GPS-based lifestyle data of middle-aged and older adults in the future.

Rest-Activity Rhythms Are Associated With Prevalent Cardiovascular Disease, Hypertension, Obesity, and Central Adiposity in a Nationally Representative Sample of US Adults

BACKGROUND

Rest-activity rhythms (RARs), a measure of circadian rhythmicity in the free-living setting, are related to mortality risk, but evidence is limited on associations with cardiovascular disease (CVD) and its risk factors.

METHODS AND RESULTS

Participants included 4521 adults from the 2013 to 2014 National Health and Nutrition Examination Survey physical activity monitoring examination. Wrist-worn ActiGraph GT3X+ data were used to estimate RARs. Multivariable logistic models evaluated associations of RARs with prevalent CVD, hypertension, obesity, and central adiposity. Participants (mean age, 49 years) in the highest versus lowest tertile of relative amplitude (greater circadian rhythmicity) had 39% to 62% lower odds of prevalent CVD, hypertension, obesity, and central adiposity. A more active wake period was associated with 19% to 72% lower CVD, hypertension, obesity, and central adiposity odds. Higher interdaily stability (regular sleep-wake and rest-activity patterns) was related to 52% and 23% lower CVD and obesity odds, respectively. In contrast, participants in the highest versus lowest tertile of intradaily variability (fragmented RAR and inefficient sleep) had >3-fold and 24% higher CVD and obesity odds, respectively. A later and less restful sleep period was associated with 36% to 2-fold higher CVD, hypertension, obesity, and central adiposity odds. A statistically significant linear trend was observed for all associations (P-trend<0.05).

CONCLUSIONS

A robust, stable, and less fragmented RAR, an active wake period, and an earlier and more restful sleep period are associated with lower prevalent CVD, hypertension, obesity, and central adiposity, with evidence of a dose-response relationship. The magnitude, timing, and regularity of sleep-wake and rest-activity patterns may be important targets for reducing cardiovascular risk.

Role of age, menopausal status, and symptoms in midlife women: Examination of sleep patterns and rest-activity circadian rhythms

BACKGROUND

Midlife women experience menopausal transition at different ages with a variety of symptoms. This study aimed to identify the effects of age, menopausal status, and symptoms in women on their actigraphy-based sleep patterns and circadian rhythms.

METHODS

A total of 87 women aged 45-60 from the community and a gynecology clinic in Taiwan who had their sleep and circadian rhythms recorded with a 7-day actigraphy were analyzed. Multiple linear regression was used to estimate the association of age, menopausal status, and symptoms with sleep parameters and circadian rhythms.

RESULTS

A sleep efficiency below 85 % was observed in 46.0 % of women, and those with severe somatic-vegetative or psychological symptoms tended to have problems with sleep latency (β = 0.22 and β = 0.42, respectively) and efficiency (β = -0.26 and β = -0.36, respectively). Women with more severe urogenital symptoms only experienced significantly longer sleep latency (β = 0.33). There was a weak correlation between circadian rhythms and symptoms. Additionally, perimenopausal (β = 0.30 and β = 0.35, respectively) and late postmenopausal (β = 0.67 and β = 0.59, respectively) women had higher relative amplitude and stability in circadian rhythms than premenopausal women. Age had no significant effect on sleep parameters or circadian rhythms.

CONCLUSIONS

Premenopausal women had the most unstable day-to-day rhythms compared to their peri- and postmenopausal counterparts. Women with higher somatic-vegetative, psychological, and urogenital symptoms showed greater sleep problems. Psychological symptoms (e.g., depression, irritability, anxiety, exhaustion) were the strongest predictors for all sleep parameters. The mechanisms underlying these associations warrant investigation.

Sleep Variability, Sleep Irregularity, and Nighttime Blood Pressure Dipping

BACKGROUND

Circadian rhythm regulates many important biological functions in humans. The goal of this study is to explore the impact of day-to-day deviations in the sleep-wake cycle on nighttime blood pressure (BP) dipping and further examine whether the ethnic difference in day-to-day deviations in sleep patterns can explain the ethnic difference in nighttime BP dipping.

METHODS

Twenty-four-hour ambulatory BP monitoring and 7-day accelerometer data were obtained from 365 adult participants (age range, 18.7-50.1 years; 52.6% Black participants and 47.3% European Americans; 64.1% females). Systolic BP dipping level was used to represent nighttime BP dipping. The SD of sleep duration was calculated as the index of sleep variability, and the SD of sleep midpoint was calculated as the index of sleep irregularity.

RESULTS

A 1-hour increase in the SD of sleep midpoint was associated with a 1.16% decrease in nighttime BP dipping (P<0.001). A 1-hour increase in the SD of sleep duration was associated with a 1.39% decrease in nighttime BP dipping (P=0.017). The ethnic difference in the SD of sleep midpoint can explain 29.2% of the ethnicity difference in BP dipping (P=0.008).

CONCLUSIONS

Sleep variability and sleep irregularity are associated with blunted BP dipping in the general population. In addition, data from the present investigation also demonstrate that the ethnic difference in sleep irregularity could partly explain the ethnic difference in BP dipping, an important finding that may help reduce the health disparity between Black participants and European Americans.

Eurycoma longifolia (Tongkat Ali) enhances wakefulness during active periods but facilitates sleep during resting periods in C57BL/6 mice

The effects of the Eurycoma longifolia (also known as Tongkat Ali [TA]) on sleep and wakefulness was evaluated in C57BL/6 mice. While TA has been used as an aphrodisiac in males, it exhibits various pharmacological effects. The most notable effect observed with TA was wake-enhancement during the second half of the active period, accompanied by significant elevations in core body temperature (CBT). In contrast, sleep was enhanced during the resting period (i.e., increase in rapid eye movement [REM] sleep and delta electroencephalography [EEG] power in non-REM sleep) with significant declines in CBT. The transition of TA's effects between resting and active periods was rapid. The results of the experiments in constant darkness indicate that TA prolongs the circadian tau and that this transition is governed by circadian clock mechanisms rather than light exposure. TA did not demonstrate efficacy in aiding sleep in an acute stress-induced insomnia model; thus, TA may be more suitable as a wake-enhancing agent for daytime sleepiness, as sleep propensity tends to accumulate towards the end of active period. Since TA amplifies the rest-activity pattern, prolongs circadian tau and increases REM sleep, thereby reversing some common symptoms seen in elderly subjects, it may also hold promise as a rejuvenating medicine.

Rest-activity rhythms across the lifespan: cross-sectional findings from the US representative National Health and Nutrition Examination Survey

STUDY OBJECTIVES

Rest-activity rhythms (RAR) may mark development, aging, and physical and mental health. Understanding how they differ between people may inform intervention and health promotion efforts. However, RAR characteristics across the lifespan have not been well-studied. Therefore, we investigated the association between RAR measures with demographic and lifestyle factors in a US nationally representative study.

METHODS

RAR metrics of interdaily stability (IS), intradaily variability (IV), relative amplitude (RA), and mean amplitude and timing of high (M10) and low (L5) activity were derived from 2011 to 2012 and 2013 to 2014 National Health and Nutrition Examination Survey (NHANES) actigraphy data. Population-weighted linear and logistic regression models were fit to examine the associations of age, gender, smoking, alcohol, season, body mass index (BMI), income-to-poverty ratio, and race/ethnicity with RAR. Significance was based on a false-discovery rate-corrected P-value of <0.05.

RESULTS

Among n = 12 526 NHANES participants (3-≥80 years), IS (higher = greater day-to-day regularity) and RA (higher = greater rhythm strength) generally decreased with age and were lower among males, whereas IV (higher = greater rhythm fragmentation) increased with age (p < 0.05). Dynamic changes in RAR trajectories were observed during childhood and adolescence. Income, BMI, smoking, and alcohol use were associated with RAR metrics, as well as season among children and teenagers (p < 0.05). RAR also differed by race/ethnicity (p < 0.05), with trajectories initially diverging in childhood and continuing into adulthood.

CONCLUSIONS

RAR differed by demographic and health-related factors, representing possible windows for public health intervention and sleep health promotion. RAR differences by race/ethnicity begin in childhood, are evident in early adolescence, and persist throughout adulthood.

Circadian rhythm disorders in patients with advanced cancer: a scoping review

Circadian rhythms can be demonstrated in several biomarkers and behavioural activities, with rhythmical patterns occurring roughly over a 24-h period. Circadian disorders occur in patients with cancer and may be associated with poor clinical outcomes. This scoping review aimed to identify circadian rhythm research and reporting practices, circadian rhythm patterns, circadian rhythm disorders, and relevant associations of circadian rhythm disorders in patients with advanced cancer. Studies involved adult patients with locally advanced or metastatic cancer and used objective measures of circadian rhythmicity. Two independent authors completed initial screening of title and abstracts, full text reviews, data extraction, and data checking. A total of 98 articles were highlighted in the scoping review, which utilised physical activity measures (actigraphy and polysomnography), biomarkers (cortisol and melatonin), or a combination. Several circadian rhythms are commonly disordered amongst patients with advanced cancer and have significant implications for symptom burden, quality of life, and survival. It remains unclear which patients are most at risk of a circadian rhythm disorder. Significant heterogeneity exists in research and reporting practices. Standardising this approach may address discrepancies in the current literature and allow for research to focus on the most relevant parameters and approaches to improving circadian rhythmicity.

Availability of Physical Activity Tracking Data from Wearable Devices for Glaucoma Patients

Physical activity has been found to potentially modulate glaucoma risk, but the evidence remains inconclusive. The increasing use of wearable physical activity trackers may provide longitudinal and granular data suitable to address this issue, but little is known regarding the characteristics and availability of these data sources. We performed a scoping review and query of data sources on the availability of wearable physical activity data for glaucoma patients. Literature databases (PubMed and MEDLINE) were reviewed with search terms consisting of those related to physical activity trackers and those related to glaucoma, and we evaluated results at the intersection of these two groups. Biomedical databases were also reviewed, for which we completed database queries. We identified eight data sources containing physical activity tracking data for glaucoma, with two being large national databases (UK BioBank and All of Us) and six from individual journal articles providing participant-level information. The number of glaucoma patients with physical activity tracking data available, types of glaucoma-related data, fitness devices utilized, and diversity of participants varied across all sources. Overall, there were limited analyses of these data, suggesting the need for additional research to further investigate how physical activity may alter glaucoma risk.

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.

Sleep, 24-hour activity rhythms, and cardiometabolic risk factors in school-age children

STUDY OBJECTIVES

Disturbed sleep and 24-hour activity rhythms are linked to adverse cardiometabolic profiles in adults and adolescents, and these associations may originate in early life. We aimed to study associations of sleep and 24-hour rhythms with cardiometabolic risk factors in school-age children.

METHODS

This cross-sectional population-based study comprised 894 children aged 8-11 years from the Generation R Study. Sleep (duration, efficiency, number of awakenings, and time awake after sleep onset) and 24-hour activity rhythms (social jet lag, interdaily stability, and intradaily variability) were assessed using triaxial wrist actigraphy for 9 consecutive nights. Cardiometabolic risk factors included adiposity (body mass index Z-score, fat mass index using dual-energy X-ray absorptiometry, and visceral fat mass and liver fat fraction using magnetic resonance imaging), blood pressure, and blood markers (glucose, insulin, and lipids). We adjusted for season, age, sociodemographics, and lifestyle factors.

RESULTS

Each increase in interquartile range of nightly awakenings (2 times) was associated with -0.12 standard deviation (95% confidence interval: -0.21, -0.04) lower body mass index and 0.15 mmol/L (0.10, 0.21) higher glucose. Among boys, an increase in interquartile range of intradaily variability (0.12) was associated with higher fat mass index (+0.07 kg/m2; 95% confidence interval: 0.03, 0.11) and visceral FM (+0.08 g; 95% confidence interval: 0.02, 0.15). We observed no associations with blood pressure or clustering of cardiometabolic risk factors.

CONCLUSIONS

Already at school age, greater fragmentation of the 24-hour activity rhythm is associated with general and organ adiposity. In contrast, more nightly awakenings were associated with lower body mass index. Future research should bring clarity to these disparate observations in order to create potential targets for obesity prevention programs.

CITATION

Beunders VAA, Koopman-Verhoeff ME, Vermeulen MJ, et al. Sleep, 24-hour activity rhythms, and cardiometabolic risk factors in school-age children. J Clin Sleep Med. 2023;19(7):1219-1229.

Onsite versus home-office: differences in sleep patterns according to workplace

Background and objective

This study aimed to evaluate the sleep patterns of students and employees working onsite versus those working from home during the COVID-19 pandemic using actigraphy.

Methods

A total of 75 students/employees (onsite: N = 40, home-office: N = 35; age range: 19-56 years; 32% male; 42.7% students, 49.3% employees) were studied between December 2020 and January 2022 using actigraphy, a sleep diary, and an online questionnaire assessing sociodemographics and morningness-eveningness. Independent-sample t-tests, paired-sample tests, and a multivariate general linear model adjusting for age (fixed factors: sex and work environment) were applied.

Results

Overall, onsite workers had significantly earlier rise times (7:05 [SD: 1:11] versus 7:44 [1:08] hours) and midpoints of sleep (2:57 [0:58] versus 3:33 [0:58] hours) on weekdays compared to home-office workers. Sleep efficiency, sleep duration, variability of sleep timing, and social jetlag did not differ between the groups.

Discussion

Home-office workers showed a delay in sleep timing that did not affect any other sleep parameters such as sleep efficiency or nighttime sleep duration. The work environment had only marginal impact on sleep patterns and thus sleep health in this sample. Sleep timing variability did not differ between groups.

Supplementary Information

The online version of this article (10.1007/s11818-023-00408-5) contains supplementary material 1 and 2, which is available to authorized users.

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.

Characterizing rest-activity rhythms and sleep for children with and without tactile sensitivities: An observational study

STUDY OBJECTIVES

This cross-sectional, observational study aimed to characterize and compare movement-based rest-activity rhythms (RARs) and sleep period variables of children with tactile hypersensitivities (SS) and non-sensitive peers (NSS) to expand the understanding of experienced differences in sleep.

METHODS

Children (ages 6-10) wore Actigraph GT9X watches for 2 weeks and caregivers completed daily sleep diaries. RARs and sleep period variables (e.g., sleep efficiency, duration, wake after sleep onset) were analyzed and localized means were plotted to visualize average rhythms for each group. Groups were compared using Student's t tests, or non-parametric alternatives, and Hedge's g effect sizes.

RESULTS

Fifty-three children and their families participated in this study (nSS = 21 nNSS = 32). The groups had similar RARs and sleep period variables. In both groups, sleep efficiency was low (SESS = 78%, SENSS = 77%) and total sleep time was short (TSTSS = 7 hrs 26 mins, TSTNSS- 7 h, 33 min) compared to national recommendations. Despite these similarities, children with SS took noticeably longer to settle down and fall asleep (53 min) than children with NSS (26 min, p = .075, g = 0.95).

CONCLUSION

This study provides preliminary data describing RAR and sleep period variables in children with and without tactile hypersensitivities. While overall RAR and sleep variables were similar between groups, there is evidence that children with SS spend a longer time transitioning to sleep. Evidence is provided that wrist-worn actigraphy is tolerable and acceptable for children with tactile sensitivities. Actigraphy provides important, movement-based data that should be used in tandem with other measures of sleep health for future studies.

Circadian rhythm biomarker from wearable device data is related to concurrent antidepressant treatment response

Major depressive disorder (MDD) is associated with circadian rhythm disruption. Yet, no circadian rhythm biomarkers have been clinically validated for assessing antidepressant response. In this study, 40 participants with MDD provided actigraphy data using wearable devices for one week after initiating antidepressant treatment in a randomized, double-blind, placebo-controlled trial. Their depression severity was calculated pretreatment, after one week and eight weeks of treatment. This study assesses the relationship between parametric and nonparametric measures of circadian rhythm and change in depression. Results show significant association between a lower circadian quotient (reflecting less robust rhythmicity) and improvement in depression from baseline following first week of treatment (estimate = 0.11, F = 7.01, P = 0.01). There is insufficient evidence of an association between circadian rhythm measures acquired during the first week of treatment and outcomes after eight weeks of treatment. Despite this lack of association with future treatment outcome, this scalable, cost-effective biomarker may be useful for timely mental health care through remote monitoring of real-time changes in current depression.

Sleep and 24-hour rhythm characteristics in preschool children born very preterm and full term

STUDY OBJECTIVES

Sleep impacts the quality of life and is associated with cardiometabolic and neurocognitive outcomes. Little is known about the sleep of preterm-born children at preschool age. We, therefore, studied sleep and 24-hour rhythms of preschool children born very preterm compared with full-term children.

METHODS

This was a prospective cohort study comparing sleep quality and quantity of children born very preterm (gestational age [GA] < 30 weeks) with full-term children at the (corrected) age of 3 years, using (1) 2 parent-reported questionnaires (Brief Infant Sleep Questionnaire and The Munich Chronotype Questionnaire) and (2) at least 3 days of triaxial wrist actigraphy combined with sleep diary. We performed regression analyses with adjustment for sex (corrected), age, and birth weight standard deviation (SD) score.

RESULTS

Ninety-seven very-preterm-born (median GA 27+5; interquartile range 26 + 3;29 + 0 weeks) and 92 full-term children (GA 39 + 3; 38 + 4;40 + 4 weeks) were included. Sleep problems and other reported sleep parameters were not different between groups. As measured with actigraphy, sleep and 24-hour rhythm were similar between groups, except for very-preterm born children waking up 21 minutes (4;38) minutes later than full-term children (adjusted P = .001).

CONCLUSIONS

Based on parent reports and actigraphy, very-preterm-born children sleep quite similar to full-term controls at the corrected age of 3 years. Reported sleep problems were not different between groups. Actigraphy data suggest that preterm-born children may wake up later than children born full term. Further studies are needed to explore how sleep relates to cardiometabolic and neurodevelopmental outcomes after preterm birth and whether early interventions are useful to optimize 24-hour rhythm and sleep.

CITATION

Bijlsma A, Beunders VAA, Dorrepaal DJ, et al. Sleep and 24-hour rhythm characteristics in preschool children born very preterm and full term. J Clin Sleep Med. 2023;19(4):685-693.

Chronobiological parameters as predictors of early treatment response in major depression

BACKGROUND

Alterations in circadian system organization have been related to major depressive disorder manifestations. This study aimed to evaluate chronobiological parameters, such as sleep, levels of 6-sulfatoxymelatonin, and others derived from actimetry as potential predictors of adequate treatment response in MDD.

METHODS

98 adult women with confirmed diagnosis of MDD were included. Participants completed standard questionnaires (Hamilton Depression Rating Scale - HAM-D; Munich Chronotype Questionnaire - MCTQ) at baseline and after 4 weeks of treatment. Urinary samples for assessing 6-sulfatoxymelatonin were collected on the day before and immediately after pharmacological treatment administration, and 28 continuous days of actigraphy data were collected during the protocol. Participants were classified into Responder (R) or Non-responder (NR) to antidepressant treatment in 4 weeks (early responder), which was characterized by a ≥50 % decrease in the HAM-D score.

RESULTS

The following biological rhythms variables significantly predicted a better treatment response in a model controlling for age, sex, and previous treatments: higher levels of activity (M10 - average activity in the 10 most active hours within the 24 h-day) and an earlier center of the 10 most active hours (M10c), as well as lower intradaily variability (IV) of light exposure. Sleep parameters and 6-sulfatoxymelatonin levels did not associate with treatment response prediction.

LIMITATION

Actimetry data were not assessed before changing in the treatment plan.

CONCLUSION

Different patterns in activity and light exposure might be linked to early antidepressant response.

Fetal and infant growth patterns, sleep, and 24-h activity rhythms: a population-based prospective cohort study in school-age children

The study objective was to explore associations of fetal and infant weight patterns and preterm birth with sleep and 24-h activity rhythm parameters at school-age. In our prospective population-based study, 1327 children were followed from birth to age 10-15 years. Fetal weight was estimated using ultrasound in the second and third trimester of pregnancy. Birth weight and gestational age were available from midwife registries. Infant weight was measured at 6, 12 and 24 months. Fetal and infant weight acceleration or deceleration were defined as a change of >0.67 standard deviation between the corresponding age intervals. At school-age, sleep duration, sleep efficiency, wake after sleep onset, social jetlag, inter-daily stability, and intra-daily variability were assessed using tri-axial wrist actigraphy for 9 consecutive nights. We observed that low birth weight (<2500 g) was associated with 0.24 standard deviation (95% confidence interval [CI] 0.04; 0.43) longer sleep duration compared to normal weight. Compared to normal growth, growth deceleration in fetal life and infancy was associated with 0.40 standard deviation (95% CI 0.07; 0.73) longer sleep duration, 0.44 standard deviation (95% CI 0.14; 0.73) higher sleep efficiency, and -0.41 standard deviation (95% CI -0.76; -0.07) shorter wake after sleep onset. A pattern of normal fetal growth followed by infant growth acceleration was associated with -0.40 standard deviation (95% CI -0.61; -0.19) lower inter-daily stability. Preterm birth was not associated with any sleep or 24-h rhythm parameters. Our findings showed that children with fetal and infant growth restriction had longer and more efficient sleep at school-age, which may be indicative of an increased need for sleep for maturational processes and development after a difficult start in life.

Sleep and Rest-Activity Rhythms in Recovering Patients with Severe Concurrent Mental and Substance Use Disorder: A Pilot Study

Objective: Mental health and substance use disorders are commonly associated with disrupted sleep and circadian rest-activity rhythms. How these disorders in combination relate to sleep and circadian organization is not well studied. We provide here the first quantitative assessment of sleep and rest-activity rhythms in inpatients with complex concurrent disorders, taking into account categories of substance use (stimulant vs. stimulant and opioid use) and psychiatric diagnosis (psychotic disorder and mood disorder). We also explore how sleep and rest-activity rhythms relate to psychiatric functioning. Methods: A total of 44 participants (10 female) between the age of 20-60 years (median = 29 years) wore wrist accelerometers over 5-70 days and completed standardized questionnaires assessing chronotype and psychiatric functioning (fatigue, psychiatric symptom severity, and impulsiveness). To examine potential influences from treatment, we computed (1) length of stay; (2) days of abstinence from stimulants and opioids as a measure of withdrawal; and (3) a sedative load based on prescribed medications. Results: Participants exhibited a sustained excessive sleep duration, frequent nighttime awakenings, and advanced rest-activity phase related to sedative load. Sleep disruptions were elevated in participants with a history of opioid use. Patients with a psychotic disorder showed the longest sleep and most fragmented and irregular rest-activity patterns. Non-parametric circadian rhythm analysis revealed a high rhythm amplitude by comparison with population norms, and this was associated with greater psychiatric symptom severity. Psychiatric symptom severity was also associated with greater fatigue and later MCTQ chronotype. Conclusions: This pilot study provides initial information on the prevalence and severity of sleep and circadian rhythm disturbances in individuals with severe concurrent disorders. The results underline the need for further studies to start to understand the role of sleep in the disease and recovery process in this understudied population.

Association of circadian rhythms with brain disorder incidents: a prospective cohort study of 72242 participants

Circadian rhythm disruption (CRD) is a shared characteristic of various brain disorders, such as Alzheimer's disease (AD), Parkinson's disease (PD), and major depression disorder (MDD). Disruption of circadian rhythm might be a risk factor for brain disorder incidents. From 7-day accelerometry data of 72,242 participants in UK Biobank, we derived a circadian relative amplitude variable, which to some extent reflected the degree of circadian rhythm disruption. Records of brain disorder incidents were obtained from a wide range of health outcomes across self-report, primary care, hospital inpatient data, and death data. Using multivariate Cox proportional hazard ratio regression, we created two models adjusting for different covariates. Then, linear correlations between relative amplitude and several brain morphometric measures were examined in participants with brain MRI data. After a median follow-up of around 6.1 years, 72,242 participants were included in the current study (female 54.9%; mean age 62.1 years). Individuals with reduced relative amplitude had increasing risk of all-cause dementia (Hazard ratio 1.23 [95% CI 1.15 to 1.31]), PD (1.33 [1.25 to 1.41]), stroke (1.13 [1.06 to 1.22]), MDD (1.18 [1.13 to 1.23]), and anxiety disorder (1.14 [1.09 to 1.20]) in fully adjusted models. Additionally, significant correlations were found between several cortical regions and white matter tracts and relative amplitude that have been linked to dementia and psychiatric disorders. We confirm CRD to be a risk factor for various brain disorders. Interventions for regulating circadian rhythm may have clinical relevance to reducing the risk of various brain disorders.

Relationship of Circadian Rhythm in Behavioral Characteristics and Lipid Peroxidation of Brain Tissues in Mice

OBJECTIVE

This study aimed to explore the relationship among several indices of circadian rhythms and lipid peroxidation of brain tissue in mice.

METHODS

After entrainment of 4-week-old mice, one group was disrupted their circadian rhythms for three days and the other group for seven days (n = 10, respectively). After a recovery period, the Y-maze test, the elevated plus maze test, the tail suspension test, and the forced swimming test were conducted. To assess lipid peroxidation in brain tissue, thiobarbituric acid reactive substances were measured in the cortex, hippocampus, and cerebellum.

RESULTS

When circadian rhythms were disrupted and adapted back to their original rhythm, the recovery time of the 7-day disruption group (median 3.35 days) was significiantly faster than one of the 3-day disruption group (median 4.87 days). In the group with a 7-day disruption, mice that had recovered their rhythms early had higher malondialdehyde levels in their hippocampus compared to those with delayed recovery. The entrainment of circadian rhythms was negatively correlated with the malondialdehyde level of brain tissue. The behavioral test results showed no differences depending on the disruption durations or recovery patterns of circadian rhythms.

CONCLUSION

These results suggest that disruption types, recovery patterns, and the entrainment of circadian rhythms are likely to affect oxidative stress in adolescents or young adult mice. Future study is needed to confirm and specify these results on the effects of circadian rhythms on oxidative stress and age-dependent effects.

Associations of circadian rest/activity rhythms with cognition in middle-aged and older adults: Demographic and genetic interactions

Objectives

Wrist actigraphs (accelerometers) can record motor activity over multiple days and nights. The resulting data can be used to quantify 24-h activity profiles, known as circadian rest-activity rhythms (CRARs). Actigraphic CRARs have been tied to cognitive performance and decline in older adults; however, little is known about links between CRARs and performance or change in specific cognitive domains, or how individual differences may influence these associations. We investigated associations of actigraphic CRARs with cognitive performance and change in middle-aged and older adults, and explored whether age, sex/gender, race, and apolipoprotein E (APOE) e4 carrier status moderated these associations.

Materials and methods

Participants (N = 422; 47% male) were cognitively healthy adults (i.e., without mild cognitive impairment or dementia) at baseline aged ≥ 50 years from the Baltimore Longitudinal Study of Aging who completed 5.6 ± 0.89 nights of wrist actigraphy and tests of memory, executive function, attention, language, and visuospatial ability at the same visit the actigraph was issued; 292 participants had repeat cognitive testing 3.12 (1.58) years later. Predictors included indices of rhythm strength [i.e., amplitude; relative amplitude (RA); interdaily stability (IS); mesor], delayed timing of the rhythm peak [i.e., later acrophase; midpoint of an individual's least active 5 h (L5 time); midpoint of an individual's most active 10 h (M10 time)], and fragmentation [i.e., intradaily variability (IV)].

Results

In main effects, later L5 time was cross sectionally associated with poorer memory, and greater IS predicted slower longitudinal memory decline. Associations of CRARs with cognition differed as a function of age, sex/gender, race, and APOE e4 carrier status.

Conclusion

Among middle-aged and older adults, delayed circadian phase is associated with poorer memory performance, and greater day-to-day rhythm stability is associated with slower declines in memory. Significant interactions suggest that CRARs are generally more strongly associated with cognitive performance and rate of cognitive decline among women, Black adults, older individuals, and APOE e4 carriers. Replication in independent samples is needed.

Circadian rest-activity misalignment in critically ill medical intensive care unit patients

Circadian alignment of rest-activity rhythms is an essential biological process that may be vulnerable to misalignment in critically ill patients. We evaluated circadian rest-activity rhythms in critically ill patients and their association with baseline (e.g. age) and clinical (e.g. mechanical ventilation status) variables, along with intensive care unit light-dark cycles. Using wrist actigraphy, we collected 48-hr activity and light exposure data from critically ill patients in a tertiary care medical intensive care unit. We evaluated circadian rest-activity rhythms using COSINOR and non-parametric circadian rhythm analysis models, and stratified these data across baseline and clinical variables. We used linear regression to evaluate the association of circadian rest-activity and light-dark exposure rhythms. In COSINOR and non-parametric circadian rhythm analysis analyses, the 34 medical intensive care unit patients completing 48-hr actigraphy recordings exhibited mean MESOR (mean activity levels of a fitted curve) and amplitudes of 0.50 ± 0.32 and 0.20 ± 0.19 movements per 30-s epoch, with high interdaily variability. Patients who were older, mechanically ventilated, sedated, restrained and with higher organ failure scores tended to exhibit greater circadian rest-activity misalignment, with three of 34 (9%) patients exhibiting no circadian rhythmicity. Circadian light-dark exposure misalignment was observed as well and was associated with rest-activity misalignment (p = 0.03). Critically ill patients in our MICU experienced profound circadian rest-activity misalignment, with mostly weak or absent rhythms, along with circadian light-dark exposure misalignment. Potentially modifiable factors contributing to rest-activity misalignment (i.e. mechanical ventilation, restraints, low daytime light levels) highlight possible targets for future improvement efforts.

The Impact of Missing Data and Imputation Methods on the Analysis of 24-Hour Activity Patterns

The purpose of this study is to characterize the impact of the timing and duration of missing actigraphy data on interdaily stability (IS) and intradaily variability (IV) calculation. The performance of three missing data imputation methods (linear interpolation, mean time of day (ToD), and median ToD imputation) for estimating IV and IS was also tested. Week-long actigraphy records with no non-wear or missing timeseries data were masked with zeros or 'Not a Number' (NaN) across a range of timings and durations for single and multiple missing data bouts. IV and IS were calculated for true, masked, and imputed (i.e., linear interpolation, mean ToD and, median ToD imputation) timeseries data and used to generate Bland-Alman plots for each condition. Heatmaps were used to analyze the impact of timings and durations of and between bouts. Simulated missing data produced deviations in IV and IS for longer durations, midday crossings, and during similar timing on consecutive days. Median ToD imputation produced the least deviation among the imputation methods. Median ToD imputation is recommended to recapitulate IV and IS under missing data conditions for less than 24 h.

Characterisation of the genetic relationship between the domains of sleep and circadian-related behaviours with substance use phenotypes

Sleep problems and substance use frequently co-occur. While substance use can result in specific sleep deficits, genetic pleiotropy could explain part of the relationship between sleep and substance use and use disorders. Here we use the largest publicly available genome-wide summary statistics of substance use behaviours (N = 79,729-632,802) and sleep/activity phenotypes to date (N = 85,502-449,734) to (1) assess the genetic overlap between substance use behaviours and both sleep and circadian-related activity measures, (2) estimate clusters from genetic correlations and (3) test processes of causality versus genetic pleiotropy. We found 31 genetic correlations between substance use and sleep/activity after Bonferroni correction. These patterns of overlap were represented by two genetic clusters: (1) tobacco use severity (age of first regular tobacco use and smoking cessation) and sleep health (sleep duration, sleep efficiency and chronotype) and (2) substance consumption/problematic use (drinks per day and cigarettes per day, cannabis use disorder, opioid use disorder and problematic alcohol use) and sleep problems (insomnia, self-reported short sleep duration, increased number of sleep episodes, increased sleep duration variability and diurnal inactivity) and measures of circadian-related activity (L5, M10 and sleep midpoint). Latent causal variable analyses determined that horizontal pleiotropy (rather than genetic causality) underlies a majority of the associations between substance use and sleep/circadian related measures, except one plausible genetically causal relationship for opioid use disorder on self-reported long sleep duration. Results show that shared genetics are likely a mechanism that is at least partly responsible for the overlap between sleep and substance use traits.

Evaluation of environmental, social, and behavioral modulations of the circadian phase of dancers trained in shifts

The interplay of environmental, social, and behavioral factors influencing human circadian phase in ecological conditions remains elusive. The Uruguayan national dance school END-SODRE operating in two shifts (morning: 8:30–12:30 and night: 20:00–24:00) allowed us to evaluate how social demands, chronotype, environmental light, physical activity, and sleep patterns affected individual circadian phase measured by the onset of the nocturnal increase of melatonin (DLMO) in a single study. The DLMO was 1.5 h earlier in morning-shift dancers (n = 7) compared to night-shift dancers (n = 11). Sleep time and chronotype (only in night-shift dancers) were associated with the circadian phase. In training days, during each participant’s phase-advance and phase-delay time windows, light exposure was similar between morning and night-shift dancers and did not correlate with DLMO. In contrast, the time spent in moderate-vigorous physical activity during each participant’s phase-lag time window was higher in night-shift dancers than in morning-shift dancers and positively correlated with DLMO.

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Circadian phase was earlier in morning than in night dancers in real-life conditions

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Sleep time (and night-shift chronotypes) correlated with the circadian phase

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In the phase-advance and phase-lag windows, light was not associated with DLMO

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In the phase-lag time window, the longer the intense exercise the later the phase

Cross-sectional study of intraocular cataract lens replacement, circadian rest–activity rhythms, and sleep quality in older adults

Study Objectives

Age-related cataract decreases light transmission at the most sensitive spectrum for circadian photoentrainment, with negative ramifications for human health. Here, we assessed whether intraocular lens replacement (IOL) in older patients with previous cataract was associated with increased stability and amplitude of circadian rest–activity rhythms, and improved sleep quality.

Methods

Our cross-sectional study included sixteen healthy older individuals without ocular diseases (controls; 55–80 years; 63.6 ± 5.6y; 8 women) and 13 patients with previous cataract and bilateral IOL (eight with blue-blocking [BB] lens and five with ultraviolet-only [UV] blocking lens; 55–80 years; 69.9 ± 5.2y; 9 women). The study comprised three weeks of at home rest–activity assessments using wrist-worn actigraphs, and each week preceded a laboratory protocol. Primary outcomes were actigraphy-derived interdaily stability, intradaily variability, and relative amplitude of circadian rest–activity rhythms. Secondary outcomes were actigraphy-assessed sleep quality (i.e. time in bed, sleep duration, sleep efficiency, mean wake bout time and fragmentation index).

Results

Patients with IOL had significantly higher interdaily stability (“Group” effect: pFDR =.001), but not intradaily variability (“Group” effect: pFDR = n.s.), and significantly higher relative amplitude of rest–activity rhythms (“Group” effect: pFDR &lt; .001). Moreover, patients with IOL had significantly higher activity levels during the day and lower levels during the evening, as compared to healthy older controls (“Group” effect: pFDR = .03). Analyses of actigraphy-derived sleep parameters yielded no significant differences across groups (“Group” effect: all pFDR &gt; .1).

Conclusions

Our cross-sectional study suggests that enhancing spectral lens transmission in patients with cataract may benefit their circadian health.

Glucose and unstructured physical activity coupling during sleep and wake in young adults with type 1 diabetes

Glucose variations have a bidirectional relationship with the sleep/wake and circadian systems in type 1 diabetes (T1D); however, the mechanisms remain unclear. The aim of this study was to describe the coupling between glucose and unstructured physical activity over 168 h in young adults with T1D. We hypothesized that there would be differences in sleep and wake characteristics and circadian variations. Glucose was measured with a continuous glucose monitoring device every 5 min and activity with a non-dominant wrist-worn actigraph in 30-s epochs over 6–14 days. There was substantial glucose and unstructured physical activity coupling during sleep and wake, along with circadian variation based on the wavelet coherence analysis. The extent to which glucose fluctuations result in disrupted sleep over longer than one week should be examined considering the harmful effects on achieving glycemic targets. Further studies are needed to delineate the respective roles of glucose production and utilization and the potential for improved meal and insulin timing to optimize glucose and sleep in this population reliant on exogenous insulin.

Rest-activity profiles among U.S. adults in a nationally representative sample: a functional principal component analysis

Background

The 24-h rest and activity behaviors (i.e., physical activity, sedentary behaviors and sleep) are fundamental human behaviors essential to health and well-being. Functional principal component analysis (fPCA) is a flexible approach for characterizing rest-activity rhythms and does not rely on a priori assumptions about the activity shape. The objective of our study is to apply fPCA to a nationally representative sample of American adults to characterize variations in the 24-h rest-activity pattern, determine how the pattern differs according to demographic, socioeconomic and work characteristics, and examine its associations with general health status.

Methods

The current analysis used data from adults 25 or older in the National Health and Nutrition Examination Survey (NHANES, 2011–2014). Using 7-day 24-h actigraphy recordings, we applied fPCA to derive profiles for overall, weekday and weekend rest-activity patterns. We examined the association between each rest-activity profile in relation to age, gender, race/ethnicity, education, income and working status using multiple linear regression. We also used multiple logistic regression to determine the relationship between each rest-activity profile and the likelihood of reporting poor or fair health.

Results

We identified four distinct profiles (i.e., high amplitude, early rise, prolonged activity window, biphasic pattern) that together accounted for 86.8% of total variation in the study sample. We identified numerous associations between each rest-activity profile and multiple sociodemographic characteristics. We also found evidence suggesting the associations differed between weekdays and weekends. Finally, we reported that the rest-activity profiles were associated with self-rated health.

Conclusions

Our study provided evidence suggesting that rest-activity patterns in human populations are shaped by multiple demographic, socioeconomic and work factors, and are correlated with health status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-022-01274-4.

Validity of chronotype questionnaires in adolescents: Correlations with actigraphy

There are only a few validated chronotype and morningness-eveningness questionnaires for adolescents. We evaluated three such questionnaires, namely Morningness-Eveningness Stability Scale improved; reduced Morningness-Eveningness Questionnaire for Children and Adolescents; and Composite Scale of Morningness in adolescents against actigraphy. Fifty-five healthy 13- to 16-year-old adolescents completed the Morningness-Eveningness Stability Scale improved, reduced Morningness-Eveningness Questionnaire for Children and Adolescents, Composite Scale of Morningness, and Pediatric Daytime Sleepiness Scale, and provided a 7-day actigraphy and sleep diary recording about their sleep-wake patterns. We examined the correlations between sleep-wake and activity parameters, and the questionnaires. The influence of age and sex on chronotype classification was studied using uni- and multivariate analyses. All three chronotype questionnaires showed good internal consistency and convergent validity. Spearman correlations reflected less daytime sleepiness, earlier sleep times, midpoints of sleep, and acrophase in morning-oriented participants. Evening-oriented participants had more sleepiness and later respective sleep-wake times. Chronotype classification differed significantly between questionnaires. The Composite Scale of Morningness classified more participants as morning types when compared with the reduced Morningness-Eveningness Questionnaire for Children and Adolescents (12 versus 7, respectively), and fewer adolescents as evening types (5 versus 9, respectively). Age and sex had no significant influence on questionnaire scores. The Morningness-Eveningness Stability Scale improved, reduced Morningness-Eveningness Questionnaire for Children and Adolescents, and Composite Scale of Morningness are valid instruments to determine circadian preference in adolescents; however, chronotype classification from the Composite Scale of Morningness and reduced Morningness-Eveningness Questionnaire for Children and Adolescents cannot be used interchangeably.

Sleep and mental health in childhood: a multi-method study in the general pediatric population

BACKGROUND

Sleep problems, altered sleep patterns and mental health difficulties often co-occur in the pediatric population. Different assessment methods for sleep exist, however, many studies only use one measure of sleep or focus on one specific mental health problem. In this population-based study, we assessed different aspects of sleep and mother-reported mental health to provide a broad overview of the associations between reported and actigraphic sleep characteristics and mental health.

METHODS

This cross-sectional study included 788 children 10-11-year-old children (52.5% girls) and 344 13-14-year-old children (55.2% girls). Mothers and children reported on the sleep of the child and wrist actigraphy was used to assess the child's sleep patterns and 24 h activity rhythm. Mental health was assessed via mother-report and covered internalizing, externalizing and a combined phenotype of internalizing and externalizing symptoms, the dysregulation profile.

RESULTS

Higher reported sleep problems were related to more symptoms of mental health problems in 10-11- and 13-14-year-old adolescents, with standardized ß-estimates ranging between 0.11 and 0.35. There was no association between actigraphy-estimated sleep and most mental health problems, but earlier sleep onset was associated with more internalizing problems (ß = - 0.09, SE = 0.03, p-value = 0.002), and higher intra-daily variability of the 24 h activity rhythm was associated with more dysregulation profile symptoms at age 10-11 (ß = 0.11, SE = 0.04, p-value = 0.002).

DISCUSSION

Reported sleep problems across informants were related to all domains of mental health problems, providing evidence that sleep can be an important topic to discuss for clinicians seeing children with mental health problems. Actigraphy-estimated sleep characteristics were not associated with most mental health problems. The discrepancy between reported and actigraphic sleep measures strengthens the idea that these two measures tap into distinct constructs of sleep.

Effect of Equine-Assisted Activities and Therapies on Cardiorespiratory Fitness in Children with Cerebral Palsy: A Randomized Controlled Trial

Abstract Objectives: To determine the effects of an equine-assisted activities and therapies (EAAT) program on cardiorespiratory fitness (CRF) in children with cerebral palsy (CP). Design: An evaluator-blinded, parallel, two-arm, randomized controlled clinical trial with 1:1 randomization. Settings/Location: A tertiary university hospital and a local arena. Subjects: Forty-six children with CP (24 boys and 22 girls) classified as Gross Motor Function Classification System levels I, II, or III were included. Interventions: The EAAT program was conducted for 40 min twice a week for 16 weeks (32 lessons). Outcome measures: Clinical global impression scales, motor capacity, cardiopulmonary fitness, and habitual physical activity was measured on both groups before and after the 16-week period. Results: Changes in the Clinical Global Impression-Severity scale and Clinical Global Impression-Improvement scale scores were not different between the groups after the intervention. Analysis of covariance revealed statistically significant differences in Gross Motor Function Measure 66 (GMFM 66) (p < 0.05) and Pediatric Balance Scale (p < 0.001) in motor capacity and resting heart rate (HRrest) (p < 0.001) in CRF, between the EAAT group and the control group. Subgroup analysis using multiple linear regression analysis revealed that the GMFM 66 changes had a statistically significant effect on the HRrest changes in the EAAT group (p < 0.05). Conclusions: The present study showed decreased HRrest in children with CP after completing the 16-week EAAT program. This improvement was explained by the improvement of GMFM 66 in the EAAT group. Thus, EAAT may be among the endurance training programs that could be offered to children with CP to improve their CRF. Clinical Trial Registration number: NCT03870893.

The effect of the transdiagnostic sleep and circadian intervention (TranS-C) on actigraphic estimates of sleep and rest-activity rhythms in adolescents with an evening circadian preference

BACKGROUND

This study evaluates whether the Transdiagnostic Sleep and Circadian Intervention for Youth (TranS-C) improves objective sleep and rest-activity rhythms in a sample of youth with an evening circadian preference (ECP).

METHODS

Youth with an ECP aged 10-18 years were randomized to receive 6 sessions of TranS-C (n = 60) or Psychoeducation (PE; n = 58). For one week prior to beginning treatment and within 2 weeks of completing treatment, participants wore an actiwatch to assess objective sleep and rest-activity rhythms.

RESULTS

Among TranS-C participants, there were significant pre-post improvements in weeknight total sleep time (TST), weekend TST, and weeknight-weekend discrepancy in TST and sleep offset time. These changes were not significant in PE. There was no significant treatment by time interactions for the sleep or rest-activity outcomes.

CONCLUSIONS

For youth with an ECP, TranS-C improves select objective sleep but not rest-activity outcomes, though compared to PE, these benefits did not reach statistical significance.

Predicting circadian phase across populations: a comparison of mathematical models and wearable devices

From smart work scheduling to optimal drug timing, there is enormous potential in translating circadian rhythms research results for precision medicine in the real world. However, the pursuit of such effort requires the ability to accurately estimate circadian phase outside of the laboratory. One approach is to predict circadian phase noninvasively using light and activity measurements and mathematical models of the human circadian clock. Most mathematical models take light as an input and predict the effect of light on the human circadian system. However, consumer-grade wearables that are already owned by millions of individuals record activity instead of light, which prompts an evaluation of the accuracy of predicting circadian phase using motion alone. Here, we evaluate the ability of four different models of the human circadian clock to estimate circadian phase from data acquired by wrist-worn wearable devices. Multiple datasets across populations with varying degrees of circadian disruption were used for generalizability. Though the models we test yield similar predictions, analysis of data from 27 shift workers with high levels of circadian disruption shows that activity, which is recorded in almost every wearable device, is better at predicting circadian phase than measured light levels from wrist-worn devices when processed by mathematical models. In those living under normal living conditions, circadian phase can typically be predicted to within 1 h, even with data from a widely available commercial device (the Apple Watch). These results show that circadian phase can be predicted using existing data passively collected by millions of individuals with comparable accuracy to much more invasive and expensive methods.

Social zeitgebers and circadian dysrhythmia are associated with severity of symptoms of PTSD and depression in trauma-affected refugees

The relation of aspects of rest-activity patterns, i.e., social zeitgebers, physical activity and circadian rhythm, to the severity of PTSD and depressive symptoms has not previously been studied. Doing so could provide valuable insight into possible targets for treatment. Our study explored these links in a population of 219 trauma-affected refugees diagnosed with PTSD who were seeking treatment. Data regarding social zeitgebers, such as affiliation with the labor market and contact with social network, and symptoms of PTSD and depression were collected from them. Furthermore, their levels of physical activity and circadian rest-activity parameters were calculated from actigraphy data. Bivariate correlation analyses and multiple linear regression analyses were performed to examine various aspects of rest-activity regarding relation to severity of PTSD and depressive symptoms. Several social zeitgebers were associated with severity of PTSD and depressive symptoms. The level of physical activity was unrelated to symptom severity, whereas a rest-activity pattern, with early onset of the most active 10 h, was associated with severity of PTSD, and a circadian rhythm with a large difference between periods of rest and activity was associated with severity of depression. Social zeitgebers, levels of physical activity and circadian rhythm parameters were all associated with each other. Social zeitgebers and circadian rhythm parameters were significantly related to the severity of PTSD and depressive symptoms-a relationship indicating that interventions targeting regularity of daily routines have a potential role in treating PTSD and depression in trauma-affected refugees.Trial registration: ClinicalTrials.gov, ID: NCT02761161, April 27, 2016.

The circadian rest-activity pattern predicts cognitive decline among mild-moderate Alzheimer's disease patients

BACKGROUND

Alterations in circadian rhythms are present in the presymptomatic stage of Alzheimer's disease (AD), possibly contributing to its pathogenesis. However, it is unknown whether such alterations are associated with worse outcomes once individuals are diagnosed with symptomatic disease. We aimed to evaluate the association between the circadian rest-activity pattern and AD-related features in patients with mild-moderate AD.

METHODS

We assessed the circadian rest-activity pattern of consecutive patients with mild-moderate AD through actigraphy for 14 days. Cerebrospinal fluid was obtained to determine the levels of important pathological markers including amyloid-beta protein (Aβ42), phosphorylated tau (P-tau), total tau (T-tau), and neurofilament light (NF-L). Neuropsychological evaluation was conducted at the beginning of the study and after 12 months of follow-up. Linear regression models were performed considering the global population and Aβ42+ patients only.

RESULTS

The cohort included 100 patients with mild-moderate AD. The median age [p25;p75] was 76.0 [73.0;80.0] years and 63.0% were female. Older age (effect size [SE] of 0.324 [0.096]; p = 0.001) and male sex (0.780 [0.193]; p = 0.001) were associated with increased fragmentation and decreased synchronization of the rhythm, respectively. After adjusting for age, sex, and season of the year, increased levels of T-tau (effect size [95% CI] of 0.343 [0.139 to 0.547]; p = 0.001) and NF-L (0.444 [0.212 to 0.676]; p = 0.001) were associated with a higher amplitude of the rest-activity rhythm. Increased fragmentation of the rhythm at baseline was associated with greater cognitive decline after one year of follow-up independent of age, sex, T-tau/Aβ42 ratio, educational level, and season of the year (- 0.715 [- 1.272 to - 0.157]; p = 0.013). Similar findings were obtained considering only the Aβ42+ patients.

CONCLUSIONS

Our results suggest a potential role of the circadian rest-activity pattern in predicting the cognitive decline of patients with mild-moderate AD. Further studies are warranted to confirm these findings and to elucidate whether there is causality among the observed associations.