Blunted rest-activity circadian rhythm increases the risk of all-cause, cardiovascular disease and cancer mortality in US adults

Exploring person-centred sleep and rest-activity cycle dynamics over 6 months

Sleep and circadian characteristics are associated with health outcomes, but are often examined cross-sectionally or using variable-centred analyses. Person-centred longitudinal research is needed to identify combined effects of sleep and circadian characteristics while allowing for change over time. We aimed to classify individuals into sleep-circadian statuses (aim 1), determine whether they transitioned between statuses over time (aim 2), and explore associated covariates and health outcomes (aim 3). Young adults (N = 151) wore smartwatches continuously for 6 months. Sleep (total sleep time, wake after sleep onset) and circadian rest-activity cycle indicators (interdaily stability, intradaily variability, relative amplitude) were derived from acceleration data and aggregated into person-means for months 1, 3, and 6. These values were entered into a latent transition model for aims 1 and 2. Multinomial logistic regressions, ANOVA, and ANCOVA addressed aim 3. Four statuses were extracted (entropy = 0.88): optimal sleepers, restless sleepers, short sleepers, and nappers. 10%-13% of optimal sleepers and 21% of restless sleepers became nappers, 7%-18% of nappers transitioned to other statuses, and 94%-100% of short sleepers remained unchanged. Males were more likely than females to be short versus optimal sleepers (p < 0.001). Restless sleepers had more physical dysfunction than nappers and short sleepers (p = 0.014, 0.022), while short sleepers reported more excessive sleepiness than optimal sleepers and nappers (p = 0.006, 0.060). This study identified four sleep-circadian statuses and found evidence for change over time. Our longitudinal person-centred approach could help inform the development of tailored diagnostic guidelines for sleep and circadian-related disorders that fluctuate within-individuals.

Rest-activity rhythm and cognitive function in older adults: A scoping review and integrative framework

Rest-activity rhythm (RAR) encompasses sleep, activity, and rest across a 24-hour cycle and over time (i.e., peak activity timing, mean activity level, activity amplitude, and rhythmicity). While the link between sleep, exercise, and cognitive function is established, the specific relationship between RAR and cognitive function in older adults remains unclear. This review synthesizes the literature on RAR and cognition, identifying 26 eligible studies from databases including PubMed, CINAHL, PsycINFO, and Web of Science. Although it was difficult to draw definitive conclusions due to the limited number of available studies focusing on each of cognitive domain and methodological heterogeneity among them, the collective findings broadly indicate that later peak activity timing, higher mean activity levels, higher activity amplitude, and more stable rhythmicity were associated with better global cognition. Future research with larger, diverse samples, more accurate RAR and cognition measurements, and incorporating biomarkers will provide deeper insights into these relationships.

Higher vulnerability to poor circadian light hygiene in individuals with a history of COVID-19

Seven-day actigraphy was performed within 1 month in 122 community-dwelling adults (mean age 24.40 y, 31 (25.4%) men) in the same city of Tyumen, Russia. Groups with different COVID-19 status (present, COVID-19(+), n = 79 vs absent, COVID-19(-), n = 43) did not differ in mean age, gender distribution, or body mass index. Vaccination status was equally represented in the COVID groups. We found that COVID-19 status, a history of SARS-CoV-2 infection, was differentially associated with daylight susceptibility. Daylight exposure was estimated using parametric and non-parametric indices: 24-h Amplitude, MESOR or M10 of white and blue light exposure (BLE) and compared between the groups. Distinctively in COVID-19(+) individuals, a smaller normalized 24-h amplitude of BLE (NAbl) was associated with lower circadian robustness, assessed by a smaller relative non-parametric amplitude (RA), a lower circadian function index (CFI), later bedtime, later onset of least active 5 h (L5), shorter total sleep duration, later phase and smaller circadian amplitude of physical motor activity. Such associations were absent in the overall COVID-19(-) population or in the vaccinated COVID(-) group. Considering COVID-status and light hygiene, defined as NAbl ≥ 1 versus NAbl < 1, only those with COVID(+) and NAbl < 1 (poorer light hygiene) had a statistically significantly delayed phase of activity and sleep, reduced circadian amplitude of physical activity, and lower circadian robustness. Accounting for gender and BMI, participants diagnosed with COVID-19 at an earlier date were older and had poorer circadian light hygiene. Altogether, our data suggest that those with COVID-19 were more vulnerable to circadian disruption due to poor circadian light hygiene, manifested as phase delay, small amplitude, a less robust circadian pattern of activity, and as delayed sleep. Our data suggest that the need for optimal circadian light hygiene is greater in individuals with a history of SARS-CoV-2 infection.

Circadian Disruption in Glaucoma: Causes, Consequences, and Countermeasures

This review explores the intricate relationship between glaucoma and circadian rhythm disturbances. As a principal organ for photic signal reception and transduction, the eye plays a pivotal role in coordinating the body's circadian rhythms through specialized retinal ganglion cells (RGCs), particularly intrinsically photosensitive RGCs (ipRGCs). These cells are critical in transmitting light signals to the suprachiasmatic nucleus (SCN), the central circadian clock that synchronizes physiological processes to the 24-hour light-dark cycle. The review delves into the central circadian body clock, highlighting the importance of the retino-hypothalamic tract in conveying light information from the eyes to the SCN. It underscores the role of melanopsin in ipRGCs in absorbing light and initiating biochemical reactions that culminate in the synchronization of the SCN's firing patterns with the external environment. Furthermore, the review discusses local circadian rhythms within the eye, such as those affecting photoreceptor sensitivity, corneal thickness, and intraocular fluid outflow. It emphasizes the potential of optical coherence tomography (OCT) in studying structural losses of RGCs in glaucoma and the associated circadian rhythm disruption. Glaucomatous retinal damage is identified as a cause of circadian disruption, with mechanisms including oxidative stress, neuroinflammation, and direct damage to RGCs. The consequences of such disruption are complex, affecting systemic and local circadian rhythms, sleep patterns, mood, and metabolism. Countermeasures, with implications for glaucoma management, are proposed that focus on strategies to improve circadian health through balanced melatonin timing, daylight exposure, and potential chronotherapeutic approaches. The review calls for further research to elucidate the mechanisms linking glaucoma and circadian disruption and to develop effective interventions to address this critical aspect of the disease.

Effects of caffeine on accelerometer measured sleep and physical activity among older adults under free-living conditions

BACKGROUND

Adequate sleep and physical activity promote longevity among older adults. Caffeine supplementation could be used to increase activity levels, but its effects have not been examined in real-world settings where potential trade-offs regarding sleep quality are also considered. This study sought to examine associations between caffeine intake and accelerometer-derived sleep and activity among older adults under free-living conditions.

METHODS

Cross-sectional data were gathered from older adults aged 65 + in the 2011-14 National Health and Nutrition Examination Surveys (NHANES). Sleep parameters were derived from accelerometer data using a data-driven machine learning approach. Caffeine consumption was categorized based on weight (in mg/kg: 0, > 0 to 1, > 1 to 2, > 2 to 3, > 3) and absolute consumption (in mg: 0, > 0 to 100, > 100 to 200, > 200 to 300, > 300). Multivariable survey weighted regression models were used to examine associations between caffeine with average total daytime activity, highly active minutes, sleep duration, and sleep efficiency. Covariate adjustments included demographics, body mass index, smoking, alcohol, sleep disorders, sleep parameters (for activity outcomes), and daytime activity (for sleep outcomes).

RESULTS

N = 1,629 NHANES participants were included. Caffeine consumption was highest in the morning. In adjusted models, older adults who consumed > 3 mg/kg were 16.5% more active during the day (95% CI: 9.0, 24.4) and were highly active for 42.8 additional minutes (95% CI: 20.3, 65.4) compared to non-consumers. Similar results were observed for absolute consumption (mg), and significant but lower magnitude effects were observed for lower levels of consumption. Caffeine showed no association with sleep efficiency, while low levels of consumption (≤ 1 mg/kg, ≤ 200 mg) were associated with longer sleep duration.

CONCLUSIONS

Under free-living dietary, sleep, and activity patterns, this study found older adults who consumed caffeine were more active than non-consumers. Overall consumption was not associated with sleep efficiency but was associated with longer sleep duration at ≤ 1 mg/kg and ≤ 200 mg. Future causal studies should determine the effectiveness of caffeine for promoting higher activity in older adult populations.

The association of 24-hour behavior rhythms with stroke among American adults with prediabetes/diabetes: evidence from NHANES 2011-2014

BACKGROUND

Emerging evidence suggests that circadian rhythms play a role in the regulation of cardiovascular diseases (CVDs). We aim to examine the relationship between the 24-hour behavior rhythms (activity-rest and feeding-fasting rhythms) and stroke.

METHODS

The study included 3201 adult participants with prediabetes/diabetes from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. The 24-hour behavior rhythm indices were calculated using data from accelerometer wearable device and dietary recall for two nonconsecutive days. Six indices were calculated including interdaily stability (IS), intradaily variability (IV), relative amplitude (RA), average activity during the least active continuous 5-hour period (L5), Average activity during the most active continuous 10-hour period (M10) which reflects the activity-rest rhythm, and feeding rhythm score which reflects the feeding-fasting rhythm. These continuous variables were divided into quintiles for logistic regression models.

RESULTS

Comparing participants in quintile 1, those in quintile 5 of IS and RA exhibited a lower odds of stroke. Conversely, participants in quintile 5 of IV, L5, and L5 start time demonstrated a higher odds of stroke. Furthermore, participants in quintile 5 of feeding rhythm score had a significantly lower odds of stroke. The associations of IV and feeding rhythm score with stroke were more pronounced in participants with diabetes compared to those with prediabetes/diabetes. No significant associations were observed between other 24-hour behavior rhythms and stroke.

CONCLUSIONS

Overall, this study highlights a significant association between 24-hour behavior rhythm and stroke in American adults with prediabetes/diabetes.

Disrupted rest-activity circadian rhythms are associated with all-cause mortality in patients with chronic kidney diseases

Circadian rhythms are important biological contributors to health. Rest activity rhythms (RAR) are emerging as biomarkers of circadian behavior that are associated with chronic disease when abnormal. RAR have not yet been characterized in chronic kidney diseases (CKD). Leveraging the National Health and Nutrition Examination Survey (2011-2014), patients with CKD (n = 1114; Mean [95% CI]: Age, 50 [58-61] y; 52% female) were compared with non-CKD individuals (n = 5885; Age, 47 [46-48] y; 52% female). Actigraphy data were processed for RAR parameters including rhythmic strength (amplitude), the rhythm adjusted mean (mesor), the timing of peak activity (acrophase), activity regularity (inter-daily stability), and activity fragmentation (intra-daily variability). Cox regression was performed to assess RAR parameters for the prediction of all-cause mortality. Compared to non-CKD adults, patients with CKD had a lower rhythmic amplitude and mesor, and exhibited greater fragmentation and less day-to-day stability in RAR (ps < 0.001). Among CKD patients, a lower rhythmic amplitude (HR [95% CI]: 0.88 [0.82-0.96]; p < 0.001), a lower rhythm adjusted mean (0.87 [0.81-0.95]; p = 0.002), and a higher daily activity fragmentation (1.87 [1.10-3.18]; p = 0.023) were associated with an increased risk of all-cause mortality. Patients with CKD showed dampened rhythmic amplitudes and greater fragmentation of activity that were associated with a higher risk of all-cause mortality. These findings demonstrate a relationship between circadian disruption and prognosis in patients with CKD.

Reliable measures of rest-activity rhythm fragmentation: how many days are needed?

BACKGROUND

A more fragmented, less stable rest-activity rhythm (RAR) is emerging as a risk factor for health. Accelerometer devices are increasingly used to measure RAR fragmentation using metrics such as inter-daily stability (IS), intradaily variability (IV), transition probabilities (TP), self-similarity parameter (α), and activity balance index (ABI). These metrics were proposed in the context of long period of wear but, in real life, non-wear might introduce measurement bias. This study aims to determine the minimum number of valid days to obtain reliable fragmentation metrics.

METHODS

Wrist-worn accelerometer data were drawn from the Whitehall accelerometer sub-study (age: 60 to 83 years) to simulate different non-wear patterns. Pseudo-simulated data with different numbers of valid days (one to seven), defined as < 1/3 of non-wear during both day and night periods, and with omission or imputation of non-wear periods were compared against complete data using intraclass correlation coefficient (ICC) and mean absolute percent error (MAPE).

RESULTS

Five days with valid data (97.8% of participants) and omission of non-wear periods allowed an ICC ≥ 0.75 and MAPE ≤ 15%, acceptable cut points for reliability, for IS and ABI; this number was lower for TPs (two-three days), α and IV (four days). Overall, imputation of data did not provide better estimates. Findings were consistent across age and sex groups.

CONCLUSIONS

The number of days of wrist accelerometer data with at least 2/3 of wear time for both day and night periods varies from two (TPs) to five (IS, ABI) days for reliable RAR measures among older adults.

Association of Rest-Activity Rhythm and Risk of Developing Dementia or Mild Cognitive Impairment in the Middle-Aged and Older Population: Prospective Cohort Study

BACKGROUND

The relationship between 24-hour rest-activity rhythms (RARs) and risk for dementia or mild cognitive impairment (MCI) remains an area of growing interest. Previous studies were often limited by small sample sizes, short follow-ups, and older participants. More studies are required to fully explore the link between disrupted RARs and dementia or MCI in middle-aged and older adults.

OBJECTIVE

We leveraged the UK Biobank data to examine how RAR disturbances correlate with the risk of developing dementia and MCI in middle-aged and older adults.

METHODS

We analyzed the data of 91,517 UK Biobank participants aged between 43 and 79 years. Wrist actigraphy recordings were used to derive nonparametric RAR metrics, including the activity level of the most active 10-hour period (M10) and its midpoint, the activity level of the least active 5-hour period (L5) and its midpoint, relative amplitude (RA) of the 24-hour cycle [RA=(M10-L5)/(M10+L5)], interdaily stability, and intradaily variability, as well as the amplitude and acrophase of 24-hour rhythms (cosinor analysis). We used Cox proportional hazards models to examine the associations between baseline RAR and subsequent incidence of dementia or MCI, adjusting for demographic characteristics, comorbidities, lifestyle factors, shiftwork status, and genetic risk for Alzheimer's disease.

RESULTS

During the follow-up of up to 7.5 years, 555 participants developed MCI or dementia. The dementia or MCI risk increased for those with lower M10 activity (hazard ratio [HR] 1.28, 95% CI 1.14-1.44, per 1-SD decrease), higher L5 activity (HR 1.15, 95% CI 1.10-1.21, per 1-SD increase), lower RA (HR 1.23, 95% CI 1.16-1.29, per 1-SD decrease), lower amplitude (HR 1.32, 95% CI 1.17-1.49, per 1-SD decrease), and higher intradaily variability (HR 1.14, 95% CI 1.05-1.24, per 1-SD increase) as well as advanced L5 midpoint (HR 0.92, 95% CI 0.85-0.99, per 1-SD advance). These associations were similar in people aged <70 and >70 years, and in non-shift workers, and they were independent of genetic and cardiovascular risk factors. No significant associations were observed for M10 midpoint, interdaily stability, or acrophase.

CONCLUSIONS

Based on findings from a large sample of middle-to-older adults with objective RAR assessment and almost 8-years of follow-up, we suggest that suppressed and fragmented daily activity rhythms precede the onset of dementia or MCI and may serve as risk biomarkers for preclinical dementia in middle-aged and older adults.

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.

The Impact of Immunotherapy on Sleep and Circadian Rhythms in Patients with Cancer

Immunotherapy has revolutionized treatments for both early and advanced cancers, and as their role evolves, their impact on sleep and circadian rhythms continues to unfold. The recognition, evaluation, and treatment of sleep and circadian rhythm disturbance leads to improved symptom management, quality of life and treatment outcomes. An intricate complex relationship exists in the microenvironment with immunity, sleep and the tumor, and these may further vary based on the cancer, addition of standard chemotherapy, and pre-existing patient factors. Sleep and circadian rhythms may offer tools to better utilize immunotherapy in the care of cancer patients, leading to better treatment outcome, reduced symptom burden, and increased quality of life.

Wearable-based accelerometer activity profile as digital biomarker of inflammation, biological age, and mortality using hierarchical clustering analysis in NHANES 2011-2014

Repeated disruptions in circadian rhythms are associated with implications for health outcomes and longevity. The utilization of wearable devices in quantifying circadian rhythm to elucidate its connection to longevity, through continuously collected data remains largely unstudied. In this work, we investigate a data-driven segmentation of the 24-h accelerometer activity profiles from wearables as a novel digital biomarker for longevity in 7,297 U.S. adults from the 2011-2014 National Health and Nutrition Examination Survey. Using hierarchical clustering, we identified five clusters and described them as follows: "High activity", "Low activity", "Mild circadian rhythm (CR) disruption", "Severe CR disruption", and "Very low activity". Young adults with extreme CR disturbance are seemingly healthy with few comorbid conditions, but in fact associated with higher white blood cell, neutrophils, and lymphocyte counts (0.05-0.07 log-unit, all p < 0.05) and accelerated biological aging (1.42 years, p < 0.001). Older adults with CR disruption are significantly associated with increased systemic inflammation indexes (0.09-0.12 log-unit, all p < 0.05), biological aging advance (1.28 years, p = 0.021), and all-cause mortality risk (HR = 1.58, p = 0.042). Our findings highlight the importance of circadian alignment on longevity across all ages and suggest that data from wearable accelerometers can help in identifying at-risk populations and personalize treatments for healthier aging.