Associations between circadian disruption and cardiometabolic disease risk: A review

Stuck in time: The slow march of circadian medicine and how to speed it up

While there is considerable enthusiasm for the translational and clinical applications of chronobiology, their actual implementation is not progressing as rapidly as might be expected. Here we discuss the possibility that this may relate to a combination of conceptual, methodological, evidentiary and training challenges. These are compounded by the remaining, profound cultural differences between basic and applied chronobiologists. We argue that all these issues can be overcome by cross-faculty teaching, time, patience and goodwill, together with a set of more formal actions, such as the establishment of a collaborative framework for evidence generation, the engagement of relevant stakeholders and public health campaigns based on already available evidence. We hope that chronobiology, and in particular the transformative power of circadian medicine, will change health outcomes, increase safety and improve quality of life for patients worldwide. Now is the time to bring "internal time" into medicine.

The Role of the Chronotype in Developing an Excessive Body Weight and Its Complications-A Narrative Review

The chronotype, the personal predisposition towards morning or evening activities, significantly influences health conditions, sleep, and eating regulations. Individuals with evening chronotypes are often at a higher risk for weight gain due to misalignment between their natural tendencies of functioning and social schedules, resulting in insufficient sleep, disruptions in eating habits, and decreased physical activity levels. Often, impaired glucose tolerance and changes in melatonin, adiponectin, and leptin secretion, along with alterations in the clock gene functions in subjects with evening preferences, may be predisposed to obesity. These disturbances contribute to metabolic dysregulation, which may lead to the subsequent onset of obesity complications, such as hypertension, type 2 diabetes, sleep apnea, and liver diseases. Targeting critical components of the circadian system and synchronizing people's chronotypes with lifestyle conditions could deliver potential strategies for preventing and treating metabolic disorders. Thus, it is recommended to take a personalized chronobiological approach to maintain a normal body weight and metabolic health. Nevertheless, future studies are needed to identify the clear mechanisms between the chronotype and human health. This article provides a narrative review and discussion of recent data to summarize studies on the circadian rhythm in the context of obesity. The manuscript represents a comprehensive overview conducted between August and November 2024 using the National Library of Medicine browser (Medline, Pub-Med, Web of Science).

Causal Effects of Air Pollution, Noise, and Shift Work on Unstable Angina and Myocardial Infarction: A Mendelian Randomization Study

Cardiovascular disease continues to be a major contributor to global morbidity and mortality, with environmental and occupational factors such as air pollution, noise, and shift work increasingly recognized as potential contributors. Using a two-sample Mendelian randomization (MR) approach, this study investigates the causal relationships of these risk factors with the risks of unstable angina (UA) and myocardial infarction (MI). Leveraging single nucleotide polymorphisms (SNPs) as genetic instruments, a comprehensive MR study was used to assess the causal influence of four major air pollutants (PM2.5, PM10, NO2, and NOx), noise, and shift work on unstable angina and myocardial infarction. Summary statistics were derived from large genome-wide association studies (GWASs) from the UK Biobank and the FinnGen consortium (Helsinki, Finland), with replication using an independent GWAS data source for myocardial infarction. The inverse-variance weighted (IVW) approach demonstrated a significant positive correlation between shift work and the increased risk of both unstable angina (OR with 95% CI: 1.62 [1.12-2.33], p = 0.010) and myocardial infarction (OR with 95% CI: 1.46 [1.00-2.14], p = 0.052). MR-PRESSO analysis identified outliers, and after correction, the association between shift work and myocardial infarction strengthened (OR with 95% CI: 1.58 [1.11-2.27], p = 0.017). No notable causal associations were identified for air pollution or noise with either outcome. The replication of myocardial infarction findings using independent data supported a possible causal link between shift work and myocardial infarction (OR with 95% CI: 1.41 [1.08-1.84], p = 0.012). These results provide novel evidence supporting shift work as a likely causal risk factor for unstable angina and myocardial infarction, underscoring the need for targeted public health strategies to mitigate its cardiovascular impact. However, further investigation is necessary to elucidate the role of air pollution and noise in cardiovascular outcomes.

Circadian disruption and its impact on the cardiovascular system

Circadian rhythms are highly conserved biorhythms of ~24 h that govern many fundamental biological processes, including cardiovascular (CV) homeostasis. Disrupting the timing of cellular oscillators promotes cellular stress, and induction of pathogenic pathways underpins the pathogenesis of many CV diseases (CVDs). Thus, shift work, late eating, sleep disturbances, and other disruptors can result in an elevated risk of heart disease and increased incidence of adverse CV events. Here, we discuss the importance of circadian rhythms for CV homeostasis, recent developments in understanding the impact of disrupted circadian rhythms on CV health and disease progression, and how understanding the interactions between circadian and CV physiology is crucial for improving interventions to mitigate CVD, especially in populations impacted by disrupted circadian rhythms.

Chrononutrition behaviors and cardiometabolic risk in adolescence: an ecological momentary assessment study

PURPOSE

To investigate the potential associations between unhealthy chrononutrition behaviors (meal timing, frequency, and regularity) and their combined impact on cardiometabolic risk in adolescence.

METHODS

Chrononutrition behaviors were assessed using a 7-day ecological momentary assessment (EMA). The unhealthy chrononutrition score (ranging from 0 to 8) was determined based on late meal timing, low meal frequency, and meal irregularity. The cardiometabolic (CM)-risk z score was calculated utilizing age- and sex-specific reference values for waist circumference (WC), mean arterial pressure (MAP), homeostatic model assessment of insulin resistance (HOMA-IR), triglycerides (TG), and high-density lipoprotein cholesterol (HDL-C). Restricted cubic splines were employed to estimate the dose-response relationships between the unhealthy chrononutrition score and outcomes.

RESULTS

Among 458 participants [mean (SD) age, 17.9 (0.7) years; 340 (74.2%) Female], 14.3% had an unhealthy chrononutrition score ≥ 6, who exhibited higher MAP (β = 3.86; 95% CI 1.24, 6.47), higher CM-risk scores (β = 1.80; 95% CI 0.70, 2.90), and lower HDL-C (β = 0.18; 95% CI - 0.30, - 0.06), as opposed to those with a healthy score ≤ 2 (n = 136, 31.4%). Moreover, late breakfast (later than 9AM compared to earlier than 8AM), low meal frequency (eating two or fewer meals versus three meals a day), and meal irregularity (score of 3-5 compared to a good score of 6-9) were associated with an increased risk of CM-risk outcomes.

CONCLUSION

The findings suggest a clustering of unhealthy chrononutrition behaviors that collectively impact cardiometabolic health in adolescence. Further prospective and interventional investigations is necessary to validate these findings and explore the underlying mechanisms.

Prevalence and Mitigation of Cardiovascular Disease Risk Factors Among the Corporate Workforce in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Cardiovascular disease (CVDs) is the leading cause of mortality worldwide. Corporate workplaces have been identified as important environmental factors that can increase the risk and severity of CVDs. Evidence indicates that the risk and severity of CVDs can be effectively reduced by mitigating modifiable behavioural and intermediate risk factors. Although the prevalence of CVDs and their associated risk factors is increasing in sub-Saharan Africa (SSA), most published data from the region are hospital-based and may not be true estimates. This study investigated the prevalence and distribution of CVD risk factors among the corporate workforce in SSA and the effects of workplace wellness programmes (WWP) on these risk factors. Accordingly, a systematic search was performed using Google Scholar, Cochrane Library, PubMed, MEDLINE, Scopus and Science Direct for articles published between January 2010 and March 2024. A total of 105 studies (n = 76,027) across nine countries met the eligibility criteria and were analysed. The pooled prevalence of the risk factors was unhealthy diet (80%), high salt intake (32%), stress (58%), poor sleep (59%), physical inactivity (PI, 59%), alcohol consumption (29%), harmful alcohol consumption (26%), tobacco smoking (7%), khat chewing (6%), overweight (36%), obesity (23%), central obesity (44%), high blood pressure (29%), high total cholesterol (33%), high low-density lipoprotein cholesterol (LDL-c) (41%), low high-density lipoprotein cholesterol (HDL-c) (45%), hypertriglyceridaemia (17%), dysglycaemia (9%), and metabolic syndrome (MS; 45%). The highest prevalence of unhealthy diet and PI was recorded in East Africa and Central Africa, respectively, whereas West Africa had the highest prevalence of high body mass index (BMI). Ethiopia had the highest prevalence of unhealthy diets, whereas Nigeria had the highest prevalence of stress and poor sleep. The healthcare sector had the highest cluster of risk factors and the highest prevalence of unhealthy diets. Only 5.7% of the studies implemented WWP, which had significant mitigating effects on most risk factors. This study concluded that the prevalence of most modifiable CVD risk factors is high among the corporate workforce in SSA, which is higher than that in the general population in most cases, and a well-designed WWP can significantly mitigate these risk factors.

Evaluating the impact of shift work on the risk of cardiometabolic disease: A Mendelian randomization study

BACKGROUND AND AIMS

Evidence is increasingly suggesting that shift work is a risk factor for cardiometabolic disease. However, the causal relationship between shift work and cardiometabolic disease is not yet fully understood. In this study, we employed two-sample Mendelian randomization (MR) to investigate the causal relationship between shift work and the risk of cardiometabolic outcomes.

METHODS AND RESULTS

Genome-wide association study (GWAS) statistics for shift work were obtained from the UK Biobank. Mendelian randomization analyses were conducted to explore the causal effects of shift work on cardiometabolic outcomes, using single-nucleotide polymorphisms (SNPs) as instrumental variables. The results suggested a causal effect between shift work and body mass index, body fat percentage, triglycerides, high-density lipoprotein, type 2 diabetes, hypertension, and cardiorespiratory fitness. After correcting for multiple tests, only body mass index and high-density lipoprotein showed significant associations. No causal effects were found between shift work and overweight, obesity, total cholesterol, low-density lipoprotein, fasting glucose, 2-h glucose, fasting insulin, coronary artery disease, myocardial infarction, heart failure, atrial fibrillation, or ischemic stroke.

CONCLUSION

This MR study provides genetic evidence for a suggestive causal link between shift work and certain cardiometabolic outcomes. Our research may have the significance of providing insight into public hygiene to improve the understanding of shift work and cardiometabolic disease risk. Further experimental studies are needed to confirm our findings.

Associations Among Cardiometabolic Risk Factors, Sleep Duration, and Obstructive Sleep Apnea in a Southeastern US Rural Community: Cross-Sectional Analysis From the SLUMBRx-PONS Study

BACKGROUND

Short sleep and obstructive sleep apnea are underrecognized strains on the public health infrastructure. In the United States, over 35% of adults report short sleep and more than 80% of individuals with obstructive sleep apnea remain undiagnosed. The associations between inadequate sleep and cardiometabolic disease risk factors have garnered increased attention. However, challenges persist in modeling sleep-associated cardiometabolic disease risk factors.

OBJECTIVE

This study aimed to report early findings from the Short Sleep Undermines Cardiometabolic Health-Public Health Observational study (SLUMBRx-PONS).

METHODS

Data for the SLUMBRx-PONS study were collected cross-sectionally and longitudinally from a nonclinical, rural community sample (n=47) in the southeast United States. Measures included 7 consecutive nights of wrist-based actigraphy (eg, mean of 7 consecutive nights of total sleep time [TST7N]), 1 night of sleep apnea home testing (eg, apnea-hypopnea index [AHI]), and a cross-sectional clinical sample of anthropometric (eg, BMI), cardiovascular (eg, blood pressure), and blood-based biomarkers (eg, triglycerides and glucose). Correlational analyses and regression models assessed the relationships between the cardiometabolic disease risk factors and the sleep indices (eg, TST7N and AHI). Linear regression models were constructed to examine associations between significant cardiometabolic indices of TST7N (model 1) and AHI (model 2).

RESULTS

Correlational assessment in model 1 identified significant associations between TST7N and AHI (r=-0.45, P=.004), BMI (r=-0.38, P=.02), systolic blood pressure (r=0.40, P=.01), and diastolic blood pressure (r=0.32, P=.049). Pertaining to model 1, composite measures of AHI, BMI, systolic blood pressure, and diastolic blood pressure accounted for 25.1% of the variance in TST7N (R2adjusted=0.25; F2,38=7.37; P=.002). Correlational analyses in model 2 revealed significant relationships between AHI and TST7N (r=-0.45, P<.001), BMI (r=0.71, P<.001), triglycerides (r=0.36, P=.03), and glucose (r=0.34, P=.04). Results from model 2 found that TST7N, triglycerides, and glucose accounted for 37.6% of the variance in the composite measure of AHI and BMI (R2adjusted=0.38; F3,38=8.63; P<.001).

CONCLUSIONS

Results from the SLUMBRx-PONS study highlight the complex interplay between sleep-associated risk factors for cardiometabolic disease. Early findings underscore the need for further investigations incorporating the collection of clinical, epidemiological, and ambulatory measures to inform public health, health promotion, and health education interventions addressing the cardiometabolic consequences of inadequate sleep.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.2196/27139.

Telomere length and chronotype among women in the California Teachers Study (CTS)

While links between certain chronotypes and poorer health outcomes have been well established in previous studies, few studies have examined the relationship between chronotype and cellular aging. Using data from the California Teachers Study (CTS), the present study evaluates the relationship between cellular aging and chronobiology through an analysis of leukocyte telomere length (LTL) and chronotype among 817 predominantly postmenopausal women with no history of cancer and occupations not associated with night-shift work. Unconditional logistic regression models were run to estimate odds ratios (ORs) for each chronotype category, adjusted for age, ethnicity, and smoking status. Analyses were then stratified by potential modifiers to assess whether results varied among specific subgroups within the sample. Women who reported being current evening types and evening types from teen years to now were significantly less likely to have short LTL compared to women who reported being current morning types or morning types from teen years to now (OR = 0.72; 95% CI = 0.53-0.98; OR = 0.57; 95% CI = 0.39-0.84). Our results suggest that women with no history of cancer who identify as evening chronotypes may undergo decreased cellular aging compared to women in the same population who identify as morning types. Further studies on populations of postmenopausal women are warranted.

Interactive correlations between artificial light at night, health risk behaviors, and cardiovascular health among patients with diabetes: A cross-sectional study

BACKGROUND

Artificial light at night (ALAN) is a common phenomenon and contributes to the severe light pollution suffered by more than 80% of the world's population. This study aimed to evaluate the relationship between outdoor ALAN exposure and cardiovascular health (CVH) in patients with diabetes and the influence of various modifiable factors.

METHODS

A survey method based on the China Diabetes and Risk Factor Monitoring System was adopted. Study data were extracted for 1765 individuals with diabetes in Anhui Province. Outdoor ALAN exposure (nW/cm2/sr) within 1000 m of each participant's residential address was obtained from satellite imagery data, with a resolution of ~1000 m. Health risk behaviors (HRBs) were measured via a standardized questionnaire. A linear regression model was employed to estimate the relationship between outdoor ALAN, HRBs, and CVH.

RESULTS

Participants' mean age was 59.10 ± 10.0 years. An association was observed between ALAN and CVH in patients with diabetes (β = 0.205) and exercise (β = -1.557), moderated by HRBs, or metabolic metrics. There was an association between ALAN, ALAN, vegetable intake, and CVH.

CONCLUSIONS

Exploring the relationship between ALAN exposure and cardiovascular and metabolic health provides policy data for improving light pollution strategies and reducing the risk of cardiovascular and metabolic disease in patients with diabetes.

Investigating the relationship between shift work schedule and blood and metabolic parameters: a 10-years retrospective cohort study

Shift work has become increasingly common in modern society. Shift work has been associated with a range of negative health outcomes. Therefore, this 10-years retrospective cohort study, aimed to investigate the relationship between shift work and blood and metabolic parameters. This retrospective cohort study was conducted in a metal parts manufacturing industry in 2023. In this study, 204 shift workers and 204 day workers were examined. All the studied blood and metabolic parameters were collected by reviewing the medical records of all participants during a 10-years period (2013-2022). Moreover, the amounts of physical, chemical, and ergonomics harmful agents in the work environment were investigated. All the collected data were analyzed using SPSS version 25.0. The values of Body Mass Index (BMI), Red Blood Cell Count (RBC), Platelets Count (PLT), Thyroid-Stimulating Hormone Level (TSH), Fasting Blood Sugar Level (FBS), Creatinine, Triglyceride (TG), Liver Enzymes level (SGOT and SGPT), and Systolic Blood Pressure (SBP) were higher among the shift work employees, and a significant difference was observed between the values of these parameters between the two groups. The results of logistic regression showed that the highest effect of shift work was observed on the parameters of FBS, TG, SGPT, TSH, Physical activity, BMI, Sleep duration, PLT, and Sleep quality with beta coefficient values of 0.49, 0.33, 0.29, 0.29, 0.20, 0.18, 0.14, 0.13 and, 0.11, respectively (p-value < 0.01). The present study contributes to a growing body of evidence that blood and metabolic factors are likely to be influenced by shift work. These findings have important implications for policy makers, highlighting the need for interventions to mitigate the negative health effects of shift work on workers.

Causal relationship between breakfast skipping and myocardial infarction: Two-sample Mendelian randomization

While observational studies suggest a connection between skipping breakfast and myocardial infarction (MI), the causal nature of this relationship is unclear. This study aims to investigate the genetic causal relationships between breakfast skipping and MI through Mendelian randomization (MR). Employing genetic data from a public genome-wide association study, this research focuses on genetic variations linked to breakfast skipping and MI. The primary analytical method was the inverse variance-weighted approach, complemented by additional methods like MR-Egger, weighted median, and mode analyses. It also includes heterogeneity and horizontal pleiotropy tests such as the Cochrane Q test, MR-Egger intercept, and MR-PRESSO tests, with a leave-one-out analysis for enhanced sensitivity assessment reliability. The study discovered a notable association between breakfast skipping and an increased risk of MI (odds ratios: 1.34, 95% confidence intervals: 1.03-1.76, P = .027). The test revealed no heterogeneity or multiplicity, and the sensitivity analysis confirmed the robustness of the results. Our MR analysis suggests that habitual breakfast skipping might elevate the likelihood of MI, underlining the importance of regular breakfast consumption in potentially mitigating heart attack risks.

Prevalence, correlates, and mental health outcomes of social jetlag in Chinese school-age adolescents: A large-scale population-based study

BACKGROUND

This cross-sectional study aimed to examine the prevalence and correlates of social jetlag (SJL) in Chinese adolescents, as well as to test the relationships between SJL and mental health problems.

METHODS

A total of 106979 students (Mage = 13.0 ± 1.8 years; Nmale = 58296 [54.5 %]) from Shenzhen, China completed an online survey from May 24th to June 5th, 2022. Information on sociodemographics, lifestyles, sleep characteristics, anxiety symptoms, and depressive symptoms was collected by a self-administered questionnaire. Multivariate and binary logistic regression were adopted for data analysis.

RESULTS

17.8 % of participants experienced SJL ≥ 2 h. To adjust the accumulated sleep debt, sleep-corrected SJL (SJLsc) was calculated and 8.3 % of individuals self-reported SJLsc ≥ 2 h. Both SJL and SJLsc show an increasing trend with age. Risk factors of SJL included females, poor parental marital status, being overweight, physically inactive, smoking, drinking, and having a late chronotype. Moreover, males, having siblings, boarding at school, short sleep duration, experiencing insomnia, and frequent nightmares were significantly associated with an increased risk of SJLsc. After adjusting for all covariates, adolescents with SJLsc ≥ 2 h were more likely to have anxiety symptoms (OR: 1.35, 95 % CI: 1.24-1.48) and depressive symptoms (OR: 1.35, 95 % CI: 1.25-1.46) than those with SJLsc < 1 h.

CONCLUSIONS

SJL is common among Chinese school-age adolescents. This study is valuable for the development of prevention and intervention strategies for SJL in adolescents at the population level. Additionally, the strong links between SJLsc and emotional problems underscore the critical significance of addressing SJL as a key aspect of adolescent well-being.

Effects of chronotype on sleep, mood and cardiovascular circadian rhythms in rotating night shift medical workers

PURPOSE

Whether chronotype affects the health outcomes of night shift work populations is unknown. This study aimed to assess the influence of different chronotypes in the rotating night shift population on sleep status, mood, blood pressure (BP), and heart rate variability (HRV), as well as the circadian rhythm of BP and HRV.

METHODS

A total of 208 rotating night shift workers were included. All participants completed structured questionnaires to assess chronotype, mood and sleep status. During their daily lives outside of the night shift, they underwent 24-hour Holter electrocardiogram monitoring and 24-hour ambulatory blood pressure monitoring. Day-time and night-time BP and BP dipping were obtained. Day-time and night-time HRV values (SDNN, RMSSD, LF, HF, LF nu, SD1, SD2 and SD2/SD1) were calculated and fitted to the cosine period curve. Three circandian parameters (mesor, amplitude and acrophase) were extracted to quantify the circadian rhythm of the HRV indices.

RESULTS

Among all three groups, E-type showed more fatigue and sleepiness. In addition, E-type showed blunted diastolic BP dipping. Notably, E-type showed association with higher RMSSD, LF, HF and SD1 in the night time, and higher mesors of RMSSD and LF and amplitude of SD2/SD1 in circadian analysis.

CONCLUSION

Chronotype is a factor affecting fatigue, sleepiness and cardiovascular circadian rhythms of rotating night shift workers. Chronotype should be taken into consideration for managing night-shift rotation to promote occupational health.

Waking Up to the Importance of Sleep in Type 2 Diabetes Management: A Narrative Review

For the first time, the latest American Diabetes Association/European Association for the Study of Diabetes (ADA/EASD) consensus guidelines have incorporated a growing body of evidence linking health outcomes associated with type 2 diabetes to the movement behavior composition over the whole 24-h day. Of particular note, the importance of sleep as a key lifestyle component in the management of type 2 diabetes is promulgated and presented using three key constructs: quantity, quality, and timing (i.e., chronotype). In this narrative review we highlight some of the key evidence justifying the inclusion of sleep in the latest consensus guidelines by examining the associations of quantity, quality, and timing of sleep with measures of glycemia, cardiovascular disease risk, and mortality. We also consider potential mechanisms implicated in the association between sleep and type 2 diabetes and provide practical advice for health care professionals about initiating conversations pertaining to sleep in clinical care. In particular, we emphasize the importance of measuring sleep in a free-living environment and provide a summary of the different methodologies and targets. In summary, although the latest ADA/EASD consensus report highlights sleep as a central component in the management of type 2 diabetes, placing it, for the first time, on a level playing field with other lifestyle behaviors (e.g., physical activity and diet), the evidence base for improving sleep (beyond sleep disorders) in those living with type 2 diabetes is limited. This review should act as a timely reminder to incorporate sleep into clinical consultations, ongoing diabetes education, and future interventions.

The association between timing of dietary macronutrient and sodium consumption and sleep duration and quality

Study Objective

The objective of this study was to examine the association between the timing of dietary macronutrients and sodium intake and sleep quantity and quality.

Methods

This was a cross-sectional study that included 34 adults between 21 and 50 years of age. The main outcome measures were objective sleep measures assessed from three nights of wrist actigraphy including sleep duration, fragmentation, and wake after sleep onset (WASO), and one night of polysomnography (PSG), including rapid eye movement (REM) sleep, non-REM stage 2 (N2), stage 3 (N3), and WASO. Multiple linear regression models and linear mixed models were used to estimate the associations between sleep measures and dietary measures (carbohydrates, fats, saturated fats, proteins, and sodium). Dietary timing was examined in two ways: (1) the average amount of each nutrient consumed within 3 hours of sleep start, and (2) the interval between the final intake of each nutrient and sleep.

Results

Average fat intake within 3 hours of sleep was associated with greater WASO from PSG (β = 4.48, p = 0.01). No other associations were found between the macronutrients or sodium intake (p > 0.05) within 3 hours of sleep and the sleep parameters from PSG or actigraphy. Similarly, no associations were found between any of the PSG or actigraphy sleep measures and the interval between final nutrient intakes and sleep with sleep duration.

Conclusions

The study suggests that greater fat but not carbohydrate, protein, saturated fat, or sodium intake close to sleep may be associated with greater sleep disruption; however, no other associations were observed.

Association of residential greenness with chronotype among children

BACKGROUND

The association between residential greenness and chronotype remains unclear, especially among children. The current study aimed to explore the associations between residential greenness and chronotype parameters in children and examine potential pathways for these associations.

METHODS

In this cross-sectional study, 16,421 children ages 3-12 were included. Two satellite-derived vegetation indices, i.e., the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI), were used to estimate residential greenness. The mid-sleep point on a workday (MSW) and the mid-sleep point on free days (MSF) were considered. And mid-sleep time on free days adjusted for sleep debt (MSFsc) was used as an indicator of chronotype. In addition to multivariable linear regression models, subgroup analyses were conducted to explore effect modifiers, and mediation analyses were used to explore possible mediating mechanisms of air pollutants underlying the associations.

RESULTS

An interquartile range (IQR) increase in both NDVI500-m and EVI500-m was significantly associated with an earlier MSFsc of -0.061 (95 % confidence interval (CI): -0.072, -0.049) and -0.054 (95 % CI: -0.066, -0.042), respectively. Non-linear dose response relationships were discovered between greenness indices and MSFsc and MSF. The results of stratified analyses showed the effect of residential greenness on MSW was stronger among primary school children and individuals with higher household income than among kindergarten children and those with lower household income. The joint mediation effects of PM2.5, PM1, PM10, NO2, and SO2 on the associations of NDVI500-m and EVI500-m with MSFsc were 89.6 % and 76.0 %, respectively.

CONCLUSIONS

Higher levels of residential greenness may have beneficial effects on an earlier chronotype in the child population, by reducing the effects of air pollutants, especially PM2.5. Our research hopes to promote the deployment of green infrastructure and healthy urban design strategies.

Alignment Between 24-h Light-Dark and Activity-Rest Rhythms Is Associated With Diabetes and Glucose Metabolism in a Nationally Representative Sample of American Adults

OBJECTIVE

The alignment between environmental stimuli (e.g., dark, light) and behavior cycles (e.g., rest, activity) is an essential feature of the circadian timing system, a key contributor to metabolic health. However, no previous studies have investigated light-activity alignment in relation to glycemic control in human populations.

RESEARCH DESIGN AND METHODS

The analysis included ∼7,000 adults (aged 20-80 years) from the National Health and Nutrition Examination Survey (NHANES) (2011-2014) with actigraphy-measured, multiday, 24-h activity and light data. We used phasor analysis to derive phasor magnitude and phasor angle, which measures coupling strength and phase difference between the activity-rest and light-dark cycles, respectively. We used multinomial logistic regression and multiple linear regression to study phasor magnitude and phasor angle in relation to diabetes (primary outcome) and multiple secondary biomarkers of glycemic control.

RESULTS

Lower alignment strength (i.e., a shorter phasor magnitude) and more delayed activity relative to the light cycle (i.e., a larger phasor angle) were both associated with diabetes. Specifically, compared with individuals in the quintiles indicating the most proper alignment (Q5 for phasor magnitude and Q1 for phasor angle), those in the quintiles with the most impaired alignment had a >70% increase in the odds of diabetes for phasor magnitude (odds ratio 1.76 [95% CI 1.39, 2.24]) and for phasor angle (1.73 [1.34, 2.25]). Similar associations were observed for biomarkers for glucose metabolism. The results were generally consistent across diverse sociodemographic and obesity groups.

CONCLUSIONS

The alignment pattern between 24-h activity-rest and light-dark cycles may be a critical factor in metabolic health.

Timing Matters: The Interplay between Early Mealtime, Circadian Rhythms, Gene Expression, Circadian Hormones, and Metabolism-A Narrative Review

Achieving synchronization between the central and peripheral body clocks is essential for ensuring optimal metabolic function. Meal timing is an emerging field of research that investigates the influence of eating patterns on our circadian rhythm, metabolism, and overall health. This narrative review examines the relationship between meal timing, circadian rhythm, clock genes, circadian hormones, and metabolic function. It analyzes the existing literature and experimental data to explore the connection between mealtime, circadian rhythms, and metabolic processes. The available evidence highlights the importance of aligning mealtime with the body's natural rhythms to promote metabolic health and prevent metabolic disorders. Specifically, studies show that consuming meals later in the day is associated with an elevated prevalence of metabolic disorders, while early time-restricted eating, such as having an early breakfast and an earlier dinner, improves levels of glucose in the blood and substrate oxidation. Circadian hormones, including cortisol and melatonin, interact with mealtimes and play vital roles in regulating metabolic processes. Cortisol, aligned with dawn in diurnal mammals, activates energy reserves, stimulates appetite, influences clock gene expression, and synchronizes peripheral clocks. Consuming meals during periods of elevated melatonin levels, specifically during the circadian night, has been correlated with potential implications for glucose tolerance. Understanding the mechanisms of central and peripheral clock synchronization, including genetics, interactions with chronotype, sleep duration, and hormonal changes, provides valuable insights for optimizing dietary strategies and timing. This knowledge contributes to improved overall health and well-being by aligning mealtime with the body's natural circadian rhythm.

Sleep disturbance and decrements in morning energy contribute to a higher symptom burden in oncology patients

OBJECTIVE/BACKGROUND

An emerging area of research is the relationship between sleep disturbance and decrements in energy. Given the paucity of research on the co-occurrence of these two symptoms, study purposes were to identify subgroups of oncology patients with distinct joint sleep disturbance AND morning energy profiles and evaluate for differences among the subgroups in demographic, clinical, and sleep disturbance characteristics, as well as the severity of other common symptoms and QOL outcomes.

PATIENTS/METHODS

Patients (n = 1336) completed measures of sleep disturbance and energy 6 times over two cycles of chemotherapy. All of the other measures were completed at enrollment. Latent profile analysis was used to identify the distinct joint sleep disturbance and morning energy profiles.

RESULTS

Three distinct profiles were identified (i.e., Low Sleep Disturbance and High Morning Energy (Normal, 20.6%), Moderate Sleep Disturbance and Low Morning Energy (Moderately Severe, 52.1%), Very High Sleep Disturbance and Very Low Morning Energy (Very Severe, 27.3%). Compared to Normal class, other two classes were more likely to be female, less likely to be employed, and had higher comorbidity burden and poorer functional status. Symptom scores and QOL outcomes exhibited a dose response effect (i.e., as the profile worsened, symptom scores increased and QOL scores decreased).

CONCLUSIONS

Given the associations between sleep disturbance and decrements in energy and a higher symptom burden, poorer QOL outcomes, and increased mortality, assessment of these two symptoms needs to be a high priority for clinicians and appropriate interventions initiated.