Shift work and chronic disease: the epidemiological evidence

BioClocks UK: driving robust cycles of discovery to impact

Chronobiology is a multidisciplinary field that extends across the tree of life, transcends all scales of biological organization, and has huge translational potential. For the UK to harness the opportunities presented within applied chronobiology, we need to build our network outwards to reach stakeholders that can directly benefit from our discoveries. In this article, we discuss the importance of biological rhythms to our health, society, economy and environment, with a particular focus on circadian rhythms. We subsequently introduce the vision and objectives of BioClocks UK, a newly formed research network, whose mission is to stimulate researcher interactions and sustain discovery-impact cycles between chronobiologists, wider research communities and multiple industry sectors.This article is part of the Theo Murphy meeting issue 'Circadian rhythms in infection and immunity'.

Dietary intake and risk assessment of nitrosamine in processed meat products among medical staff during their night shift

The study aims to evaluate the levels of nitrosamine, a known carcinogenic compound, in processed meat products and to assess its dietary intake and margin of exposure among medical staff, including physicians, pharmacists, and nurses working night shifts at Alexandria University Hospitals. Additionally, the study seeks to evaluate the participants' knowledge of dietary sources and regulatory limits of carcinogens. A cross-sectional study was conducted with 420 participants. Results showed that hotdogs contained the highest nitrosamine levels (159.24 ± 87.99 µg/g) with a consumption pattern of 0.02126 µg/kg BW/day. In contrast, sausages and burgers had the lowest nitrosamine content (2.36 µg/g and 2.37 µg/g, respectively). Luncheon meat also exhibited low nitrosamine levels and consumption patterns, at 18.53 µg/g and 0.00141 µg/kg BW/day, respectively. The Margin of Exposure (MOE) was calculated to assess risk, with a Benchmark Dose Lower Confidence Limit (BMDL)10 value of 29 µg/kg BW/day as the reference point. MOE values ≥ 17,000, derived for nitrosamine exposure in this study, indicate a low level of concern for carcinogenic risk. A statistically significant difference in dietary nitrosamine intake was observed across different professions among the medical staff (p < 0.001).

Impact of Physical and Psychological Strain on Work-Related Musculoskeletal Disorders: A Cross-Sectional Study in the Construction Industry

This study examined the interplay between physical workload, psychological stress, and the prevalence of work-related musculoskeletal disorders (WMSDs) among construction workers in Indonesia. This cross-sectional study used a purposive sampling technique to gather quantitative data from 409 respondents working in four construction companies through structured questionnaires. Data collection tools included the Copenhagen Psychosocial Questionnaire III (COPSOQ III), the K10 scale for psychosocial distress, and the Nordic Body Map for musculoskeletal symptoms. Independent variables encompassed demographic factors, physical work environment, and psychosocial aspects, while the dependent variable was the presence of work-related musculoskeletal disorders (WMSDs) symptoms over the past 7 days and 12 months. Descriptive statistics and logistic regression analyses were performed using IBM SPSS Statistics Grad Pack 29.0 PREMIUM. The study revealed a high prevalence of WMSDs among workers, with 36.2% reporting symptoms in the past 7 days and 31.5% in the past 12 months. These symptoms primarily affected the neck, shoulders, back, and waist. Both physical and psychosocial factors were found to the risk, with high levels of somatic stress and sleep disorders significantly increasing the likelihood of WMSDs. Psychological distress emerged as a particularly strong predictor to these disorders. The findings underscore the importance of implementing targeted interventions and safety policies to mitigate WMSDs risks and improve occupational health within the construction industry.

Views and Experiences of Nurses Receiving Care as Inpatients: An Empirical Qualitative Study From Ankara

AIM

To determine the views and experiences of inpatient nurses receiving care.

BACKGROUND

Switching from the care provider role to being a patient allows nurses to realise patients' real care expectations and to test their colleagues' care practices. Nurses' experience as inpatients is essential for understanding patients' care-related expectations and improving care quality by reflecting on their practices.

DESIGN

This qualitative study used a descriptive phenomenological design.

METHODS

Data were collected from nine volunteer nurses between July 2018 and June 2020 in Ankara, Türkiye, through face-to-face interviews using semi-structured questionnaires and audio recordings. The research data were analysed by following the descriptive phenomenological data analysis steps. The Consolidated Criteria for Reporting Qualitative Research [COREQ] checklist was used to report study findings.

RESULTS

Three themes emerged from the views and experiences of nurses receiving inpatient care: care-receiving experiences, components of good nursing care and change in perception of care.

CONCLUSION

It is important to reveal the opinions and experiences of hospitalised nurses regarding care to understand the expectations of the care recipients and to increase the quality of the care provided. The study revealed that the experiences of nurses receiving inpatient care improved their professional sensitivity and this was reflected in the quality of the nursing care they provided.

IMPLICATION FOR NURSING

Nurses can provide higher quality and humanistic care by combining their professional knowledge and skills with the increased awareness of the inpatient experience of nurses. No patient or public contribution.

The Impact of Poor Sleep Quality on Cardiovascular Risk Factors and Quality of Life

This review article examines the impact of poor sleep quality on cardiovascular risk factors and quality of life. Insufficient sleep and disturbances in sleep have been linked to a variety of negative health outcomes, including an increased risk of cardiovascular disease, elevated blood pressure, obesity, and a reduced quality of life. This review explores the available evidence connecting poor sleep with these health conditions, analyzing the underlying mechanisms and pathways involved. Additionally, the challenges posed by night work, which can contribute to poor sleep and subsequent health problems, are discussed. The review also discusses evidence-based strategies for improving sleep quality, encompassing sleep hygiene practices, bright light therapy, cognitive behavioral therapy for insomnia, pharmacological interventions, and emerging digital health solutions. The aim is to analyze current research and emphasize the crucial role of prioritizing sleep quality in maintaining both cardiovascular health and quality of life.

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.

Cross-sectional analysis of the association between information and communication technology and mental health among Korean workers

BACKGROUND

The adoption of information and communication technology (ICT) has been the fastest and most widespread in the South Korean workplace. While ICT has several advantages, it can also cause stress among workers. However, the relationship between the introduction of ICT in the workplace and mental health problems among Korean workers remains unclear.

METHODS

We conducted a cross-sectional analysis of data obtained from the sixth Korean Working Conditions Survey (KWCS). In total, 40,019 participants answered a question about whether ICT had been introduced in their workplace. Among these, we compared the rate of complaints of mental health disorders between those who answered "yes" (n = 3,250) and those who answered "no" (n = 36,769). We analyzed the data using the SAS statistical software and calculated the odds ratios (ORs) and 95% confidence intervals (95% CIs) for anxiety, insomnia, and depression using multiple logistic regression models. We also stratified the data on Korean workers to assess the impact of ICT on subgroups.

RESULTS

In our nationally representative cohort, on experiencing ICT incorporation at work, 384 participants (11.8%) reported anxiety, 138 (4.2%) reported insomnia, and 296 (9.1%) reported depression. In contrast, among participants who did not have access to ICT, 1,929 (5.2%) reported anxiety, 702 (1.9%) reported insomnia, and 4,404 (12.0%) reported depression. The ORs (95% CIs) for anxiety and insomnia complaint rates were 2.47 (2.19-2.79) and 2.55 (2.10-3.10), respectively, among workers who experienced new ICT adaptations in comparison with those who did not. However, no significant relationship was observed between ICT adoption and depression.

CONCLUSIONS

The causes of mental health problems in the workplace should be identified and addressed. We found that the introduction of ICT in the workplace was significantly related to anxiety and insomnia symptoms among Korean workers, after controlling for the selected covariates. This information can be used to identify subgroups in the workplace that are vulnerable to ICT changes and tailor interventions to their social and demographic profiles.

Interoceptive inference and prediction in food-related disorders

The brain's capacity to predict and anticipate changes in internal and external environments is fundamental to initiating efficient adaptive responses, behaviors, and reflexes that minimize disruptions to physiology. In the context of feeding control, the brain predicts and anticipates responses to the consumption of dietary substances, thus driving adaptive behaviors in the form of food choices, physiological preparation for meals, and engagement of defensive mechanisms. Here, we provide an integrative perspective on the multisensory computation between exteroceptive and interoceptive cues that guides feeding strategy and may result in food-related disorders.

Night shift work and myocardial infarction in the UK Biobank

BACKGROUND

Shift work has become popular along with adverse effects such as disrupted biological rhythms, metabolic changes, sleep disorders and myocardial infarction. Studies have shown a link between myocardial infarction and shift work, but evidence is still lacking.

AIMS

We aim to explore the association between present and past shift work and risk of myocardial infarction in a large population of European workers.

METHODS

We analysed data from the UK Biobank with >500 000 participants and an average 12-year follow-up duration. Cox proportional hazard models were employed to analyse the relationship between present shift work (n = 265 064), lifetime duration or frequency of shift work (n = 71 428) and the risk of myocardial infarction, as well as the association between rest day during shift work and myocardial infarction incidents in night shift workers (n = 14 588).

RESULTS

Night shift workers had a higher risk of myocardial infarction compared to day workers, including 'shift but never/rarely night shifts' (hazard ratio [HR] = 1.09, 95% confidence interval [CI] 1.00-1.20), 'some night shifts' (HR = 1.13, 95% CI 1.01-1.27) and 'usual/permanent night shifts' (HR = 1.21, 95% CI 1.07-1.37), respectively. Similarly, higher frequency and longer duration of night shift work were associated with the increased risk of myocardial infarction (<10 years: HR = 1.20, 95% CI 1.01-1.42; ≥10 years: HR = 1.51, 95% CI 1.28-1.77; or an average of more than eight nights per month: HR = 1.45, 95% CI 1.23-1.71). However, longer rest days couldn't decrease myocardial infarction risk compared to those who rest 1 day.

CONCLUSIONS

Present and lifetime exposure to night shifts were associated with a risk of myocardial infarction and did not benefit from longer rest days.

Personalized sleep and nutritional strategies to combat adverse effects of night shift work: a controlled intervention protocol

BACKGROUND

Working during the night interferes with the timing of normal daily activities and is associated with an increased risk of chronic diseases. Under controlled experimental conditions, interventions focusing on sleep and nutrition can mitigate the short-term adverse effects of shift work. However, it is unclear how these results translate to real-life, how they can be targeted to individual conditions, and how they relate to long-term health. Therefore, the current study aims to implement a personalized sleep and nutritional intervention among night shift workers in the field.

METHODS

A non-blinded controlled intervention study is used, consisting of a run-in period, an intervention of 3 months, post-intervention measurements, and a follow-up after 12 months. Three study arms are included: sleep intervention, nutritional intervention, and control group (n = 25 each). Participants are healthy 18-60-year male night shift workers, with at least one year of experience in night shift work. Information from the run-in period will be used to personalize the interventions. The main outcomes are sleep measurements and continuous interstitial glucose levels. Furthermore, general health biomarkers and parameters will be determined to further evaluate effects on long-term health.

DISCUSSION

This study aims to mitigate negative health consequences associated with night shift work by introducing two personalized preventive interventions. If proven effective, the personalized interventions may serve as practical solutions that can have a meaningful impact on the sustainable health and employability of night shift workers. This study will thereby contribute to the current need for high-quality data on preventative strategies for night shift work in a real-life context.

TRIAL REGISTRATION

This trial has been registered under ClinicalTrials.gov Identifier NCT06147089. Registered 27 November 2023.

Influence of Night Shift Work on Heart Rate Variability in an Age- and Gender-Matched Study Group

Regular and long-term shift work is associated with a number of chronic diseases. There is some evidence that shift work also has an influence on the autonomous nervous system. Studies that have examined the effect of shift work on heart rate variability (HRV) have not taken into account age and gender. Therefore, the aim of this study was to investigate the influence of night shift based on 24 h long-term analyses carried out on non-night shift days with a matched control group for age and gender. In total, 172 (128 male, 44 female) healthy shift night workers were compared with subjects from a non-night shift worker group at a ratio of 1:1, forming matched pairs based on the subjects' sex and age. HRV parameters were analyzed based on 24 h ECG recording. An analysis of the HRV parameters showed only a small difference but without statistical significance between the two groups with regard to all of the HRV parameters examined (SDNN, RMSSD, NN50, pNN50, VLF, LF, HF, LF/HF, DFA1, and DFA2). An analysis of the subgroup of subjects who had only worked night shifts for a minimum of 10 or 20 years, with the respective pairs matched by age and gender, did not reveal any significant differences between the HRV parameters of employees working night shifts and those not working night shifts. Taking into account qualitative aspects of HRV analysis, this study was thus able to show that working night shifts for many years may not have as big an influence on HRV as had been assumed so far.

Factors affecting blood sugar changes in diabetic patients using a three-level model in analysis of longitudinal data

Background

Diabetes, a currently threatening disease, has severe consequences for individuals' health conditions. The present study aimed to investigate the factors affecting the changes in the longitudinal outcome of blood sugar using a three-level analysis with the presence of missing data in diabetic patients.

Methods

A total of 526 diabetic patients were followed longitudinally selected from the annual data collected from the rural population monitored by Tonekabon health centers in the North of Iran during 2018-2019 from the Iranian Integrated Health System (SIB) database. In analyzing this longitudinal data, the three-level model (level 1: observation (time), level 2: subject, level 3: health center) was carried out with multiple imputations of possible missing values in longitudinal data.

Results

Results of fitting the three-level model indicated that every unit of change in the body mass index (BMI) significantly increased the fasting blood sugar by an average of 0.5 mg/dl (p=0.024). The impact of level 1 (observations) was insignificant in the three-level model. Still, the random effect of level 3 (healthcare centers) showed a highly significant measure for health centers (14.62, p<0.001).

Conclusion

The BMI reduction, the healthcare centers' socioeconomic status, and the health services provided have potential effects in controlling diabetes.

An atlas of the human liver diurnal transcriptome and its perturbation by hepatitis C virus infection

Chronic liver disease and cancer are global health challenges. The role of the circadian clock as a regulator of liver physiology and disease is well established in rodents, however, the identity and epigenetic regulation of rhythmically expressed genes in human disease is less well studied. Here we unravel the rhythmic transcriptome and epigenome of human hepatocytes using male human liver chimeric mice. We identify a large number of rhythmically expressed protein coding genes in human hepatocytes of male chimeric mice, which includes key transcription factors, chromatin modifiers, and critical enzymes. We show that hepatitis C virus (HCV) infection, a major cause of liver disease and cancer, perturbs the transcriptome by altering the rhythmicity of the expression of more than 1000 genes, and affects the epigenome, leading to an activation of critical pathways mediating metabolic alterations, fibrosis, and cancer. HCV-perturbed rhythmic pathways remain dysregulated in patients with advanced liver disease. Collectively, these data support a role for virus-induced perturbation of the hepatic rhythmic transcriptome and pathways in cancer development and may provide opportunities for cancer prevention and biomarkers to predict HCC risk.

The influence of night shift work and associated factors on serum uric acid in aircraft maintenance workers

BACKGROUND AND OBJECTIVE

The prevalence of 12-hour shift work is increasing in various occupations. Shift work has been linked to circadian rhythm disruption, which may lead to hormonal changes and metabolic disorders, including alterations in glucose, lipid, and purine metabolism. Despite this, there is limited research on the potential connection between work shifts and abnormal serum uric acid (SUA) levels. Furthermore, the factors that contribute to abnormal SUA levels in shift workers are not well-understood. Therefore, this study aimed to analyze the SUA levels of shift workers employed in an aircraft maintenance company, investigate the potential association between shift work and SUA levels, and explore the factors that may influence abnormal SUA levels in shift workers.

METHODS

A total of 2263 male workers from an aircraft maintenance company were included in this study using the cluster sampling method. The workers were divided into two groups based on their working shifts: night shift (N = 1047, 46.27%) and day working (N = 1216, 53.73%). A survey was conducted between April 1st and June 30th, 2022 to gather information on work, lifestyle, physical examination results, and other relevant factors. The survey included a self-designed demographic information questionnaire to collect data on workers' characteristics, medical history, years of employment, smoking and drinking habits, and main lifestyle behaviors. The workers' SUA levels were measured using uricase colorimetry. One-way ANOVA was used to compare the difference in the abnormal detection rate of SUA between the two groups, and multi-factor logistic regression analysis was used to identify the factors that influence abnormal SUA levels.

RESULTS

The study indicated that 48.9% of night shift workers and 43.8% in the regular day workers had abnormal SUA levels, with a significant difference between the two groups (χ2 = 6.125, P = 0.013). Factors such as circadian rhythm type, shift work, age, the taste of diet, type of diet, smoking, overweight or obesity based on body mass index (BMI), concentration of urine creatinine (CREA), total cholesterol, triglyceride, and low-density lipoprotein cholesterol were found to be correlated with SUA abnormalities (P < 0.05). The risk of developing SUA abnormalities was found to be higher in individuals with an intermittent (OR = 1.34, 95% CI: 0.83-2.12, P < 0.05) or evening circadian rhythm type (OR = 1.45, 95% CI: 0.86-2.43, P > 0.05) compared to those with a morning type. Additionally, factors such as night shift work, a high-sodium diet, smoking, a diet high in meat and low in vegetables, being overweight or obese, and higher levels of CREA were also found to increase the risk of developing SUA abnormalities. The study also revealed a significant dose-response relationship between BMI and abnormal uric acid levels. After controlling for other factors, the risk of developing SUA abnormalities was found to be 1.18 times higher in the night shift work group than in the day work group (OR = 1.18, 95% CI:1.02-1.34, P = 0.01).

CONCLUSION

Shift work has been linked to a higher risk of developing SUA abnormalities, and there are several factors that may contribute to this risk. To prevent diseases, it is recommended that enterprises implement better health monitoring and management practices for shift workers.

A low-calorie meal replacement improves body composition and metabolic parameters in shift workers with overweight and obesity: a randomized, controlled, parallel group trial

BACKGROUND

Shift work has been identified as a risk factor for several chronic health conditions including obesity. This study evaluated the impact of a low-calorie meal replacement (MR) as a dinner substitute on body composition and metabolic parameters in shift workers with overweight and obesity.

METHODS

An 8-week parallel, randomized controlled trial was conducted on overweight and obese shift workers in a large hospital. An intervention group (IG) (n = 25) was provided with a low-calorie MR shake (∼200 kcal) as a replacement for dinner, every day for 8 weeks, while the control group (CG) (n = 25) continued their habitual diet. Anthropometric measurements, body composition, biochemical, and lifestyle data were assessed at the first and last visits. Analyses were done per protocol (PP) and by intention to treat (ITT).

RESULTS

Over the study duration, both groups displayed moderate changes in anthropometric measurements and body composition, although these were not statistically significant according to the PP analysis. In the ITT analysis, apart from the hip circumference (HC), all other anthropometric parameters demonstrated significant group and time interactions, suggesting the advantageous effects of the meal replacement over the study period (P < 0.05). HDL and VLDL cholesterol measures showed significant main effects, influenced by both group (P = 0.031) and time (P = 0.050) respectively. The most pronounced dietary shift in the IG was a reduction in carbohydrate consumption and an increase in protein intake. Throughout the study, the meal replacement was well-tolerated, with no adverse events reported.

CONCLUSIONS

The meal replacement dietary intervention appears to offer beneficial health effects over time. Extended research is crucial to understand the broader implications of meal replacements across diverse populations.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12622000231741. Registered on 09 February 2022. https://www.anzctr.org.au/ACTRN12622000231741.aspx .

The Development and Validation of the Health Belief Model for Shift Workers (HBM-SW) Scale

OBJECTIVE

Shift work is associated with circadian misalignment, sleep loss, and suboptimal health behaviors, which may contribute to longer term negative health outcomes. To inform future interventions for shift workers, the present study aimed to develop and evaluate the Health Belief Model for Shift Workers (HBM-SW) scale.

METHODS

The HBM-SW development involved a seven-step process, including a literature review, expert panel analysis, cognitive interviews with shift workers, and a trial with a pilot sample of shift workers (n = 153). Utilizing exploratory factor analysis for factor identification and item reduction, the developed scale loaded on seven factors in line with the theoretical framework of the Health Belief Model: Perceived Threat, Perceived Severity, Perceived Benefits, Perceived Barriers, Cues to Action, Self-efficacy, and Health Motivation. Validation of the scale was conducted utilizing Pittsburgh Sleep Quality Index, International Physical Activity Questionnaire, and Food Frequency Questionnaire.

RESULTS

The pilot sample had an average age of 34.0 (18.0) years, was majority female (54.2%), with an average of 8.0 (11.0) years shift work experience. The HBM-SW showed good - excellent (α = 0.74-0.93) internal consistency and moderate - good (ICC = 0.64-0.89) test re-test reliability. Using health behavior outcome measures, the HBM-SW scale showed meaningful correlations with sleep quality, sleep duration, diet quality and leisure time physical activity, and acceptable validity and reliability. Further testing should be conducted in a larger sample to facilitate confirmatory factor analysis.

CONCLUSIONS

The developed Health Belief Model for Shift Workers scale is likely beneficial for use in future studies of interventions for shift workers.

Circadian disturbances by altering the light-dark cycle negatively affects hematopoietic function of bone marrow in mice

Circadian rhythms in metabolically active tissues are crucial for maintaining physical health. Circadian disturbance (CD) can cause various health issues, such as metabolic abnormalities and immune and cognitive dysfunctions. However, studies on the role of CD in immune cell development and differentiation, as well as the rhythmic expression of the core clock genes and their altered expression under CD, remain unclear. Therefore, we exposed C57bl/6j mice to repeated reversed light-dark cycles for 90 days to research the effects of CD on bone marrow (BM) hematopoietic function. We also researched the effects of CD on endogenous circadian rhythms, temporally dependent expression in peripheral blood and myeloid leukocytes, environmental homeostasis within BM, and circadian oscillations of hematopoietic-extrinsic cues. Our results confirmed that when the light and dark cycles around mice were frequently reversed, the circadian rhythmic expression of the two main circadian rhythm markers, the hypothalamic clock gene, and serum melatonin, was disturbed, indicating that the body was in a state of endogenous CD. Furthermore, CD altered the temporally dependent expression of peripheral blood and BM leukocytes and destroyed environmental homeostasis within the BM as well as circadian oscillations of hematopoietic-extrinsic cues, which may negatively affect BM hematopoiesis in mice. Collectively, these results demonstrate that circadian rhythms are vital for maintaining health and suggest that the association between CD and hematopoietic dysfunction warrants further investigation.

The Effect of Shift Working on Dietary Patterns of Healthcare Practitioners during the COVID-19 Pandemic: A Cross-Sectional Study

Background and Objectives: Health professionals' working schedules often do not allow them to follow a balanced way of life, and the nature of their work can affect their weight and eating habits. The aim of the present study is to shed some light on the impact of night shift working on the dietary practices of healthcare practitioners in Greece. Materials and Methods: This was a cross-sectional study. With the use of an administered questionnaire several parameters were assessed, including anthropometric characteristics, weight history, as well as nutritional habits of the same group of participants during night shifts and when at regular working hours. Moreover, nutritional beliefs of the subjects were recorded, as well as the level of adherence to the Mediterranean diet. Results: It was observed that in all food groups, including water, used to compare the nutritional patterns of the participants during night shifts and when working regular hours, statistical differences were noted (p = 0.001). Furthermore, the participants who reported a higher adherence to the Mediterranean diet and self-reported healthier nutritional habits, had a statistically lower weight compared to the participants that rarely followed the specific model or reported unhealthier eating routine (p = 0.010 and p = 0.015, respectively). Conclusions: We conclude that shift-working healthcare professionals are associated with disturbed eating behaviours leading to the high consumption of unhealthy food. The implementation of interventions that will concentrate on educating health workers on balanced nutrition and improving physical environment (i.e., food availability, healthier food choices) seems to be of great importance.

The influence of shift work: A bibliometric analysis of research progress and frontiers on health effects

Shift work has been found to disrupt the circadian system, leading to negative health effects. The objective of this study was to assess the progress and frontiers in research on the health-related influence of shift work. The study analyzed 3,696 data points from Web of Science, using the bibliometric software CiteSpace to visualize and analyze the field. The results showed a steady increase in annual publications, particularly in the last 5 years, with a rapid increase in publications from China. The United States contributed the most to the number of publications and worldwide collaborations. The most prolific institution and author were the Brigham and Women's Hospital and Professor Bjorn Bjorvatn, respectively. The Journal of Chronobiology International ranked at the top and focused primarily on shift worker research. In the first decade of study, the primary focus was on the associations between shift work and cardiovascular disease and metabolic disorders. Over time, research on the health effects of shift work has expanded to include cancer and mental health, with subsequent studies investigating molecular mechanisms. This study provides a comprehensive and intuitive analysis of the negative health impacts of shift work. It highlights existing research hotspots and provides a roadmap for future studies. Further research is needed to explore the adverse health consequences and related mechanisms of shift work exposure, as well as interventions to mitigate its health effects.

Rotating shift work time is directly associated with excess body adiposity

OBJECTIVE

To analyze the association between changes in body adiposity and length of service on a schedule of rotating shifts.

METHODS

The study was a cross-sectional investigation conducted during the years 2012, 2015, and 2018, involving individuals engaged in rotating shifts at a company involved in iron ore extraction situated within the Iron Quadrangle region of Minas Gerais and the southeastern region of Pará, Brazil. Sociodemographic and behavioral data were collected along with anthropometric parameters in order to calculate body mass index (BMI) and the waist-to-height ratio (WHtR). For data analysis, a multivariate logistic regression was employed to explore potential associations between indicators of body adiposity and the duration of shift work, employing a hierarchical determination model.

RESULTS

The findings showed that in the multivariate model, controlling for confounding factors, workers with 5 to 10, 10 to 15, and more than 15 years of shift work had 41 to 96% greater odds of being overweight (BMI > 25.0 kg/m2), 71 to 82% of having altered neck circumference (> 40 cm), 33 to 120% of altered WC (>102 cm), and 57 to 214% of having altered WHtR (> 0.5 cm).

CONCLUSION

The findings suggest that time spent in work has a significant effect on anthropometric indicators of body adiposity, especially if the worker has a previously established comorbidity such as dyslipidemia or hypertension and is frequently exposed to night work.

A systematic review of associations between day-to-day variability in meal pattern and body weight, components of the metabolic syndrome and cognitive function

BACKGROUND

Meal pattern is a potential health determinant. Previously, mean values for properties of meal pattern, such as daily meal frequency, have been considered. Means, however, obscure variability between-day (irregular or chaotic eating). This systematic review aimed to identify and critique published methods used to characterise between-day variability in meal pattern, and to explore relationships between this and obesity, as well as associated health outcomes.

METHODS

Using relevant databases, a systematic search was undertaken for studies with adults and children in which between-day variability in meal pattern was measured, and related to body weight, metabolic syndrome components and cognitive function.

RESULTS

In 34 papers identified (28 observational and six intervention studies), between-day variability in meal pattern was characterised by a variety of methods. These ranged from single questions about intake regularity to more complex methods quantifying the degree of variability. Assumptions were made, such as there being three main meals, resulting in dissociation from the "clock time" of eating. In 24 of the papers, between-day variability in meal pattern was associated with negative weight and health outcomes including higher weight, reduced thermogenic response to meals and poorer academic achievement.

CONCLUSIONS

Between-day variability in meal pattern is a promising research area that might inform low-cost public health interventions. However, current methods of characterising between-day variability tend to make assumptions and be inconsistent in the meal pattern properties considered. Well controlled dietary intervention studies are required to confirm causation.

Association between Shift Work and Health Outcomes in the General Population in China: A Cross-Sectional Study

Shift work may adversely affect individuals' health, thus, the current study aimed to investigate the association between shift work and health outcomes in the general population. A total of 41,061 participants were included in this online cross-sectional survey, among which 9612 (23.4%) individuals engaged in shift work and 31,449 (76.6%) individuals engaged in non-shift work. Multiple logistic regression analyses were conducted to explore the association between shift work and health outcomes (psychiatric disorders, mental health symptoms, and physical disorders). In addition, associations between the duration (≤1 year, 1-3 years, 3-5 years, 5-10 years, ≥10 years) and frequency of shift work (<1 or ≥1 night/week) and health outcomes were also explored. The results showed that compared to non-shift workers, shift workers had a higher likelihood of any psychiatric disorders (odds ratios [OR] = 1.80, 95% CI = 1.56-2.09, p < 0.001), mental health symptoms (OR = 1.76, 95% CI = 1.68-1.85, p < 0.001), and physical disorders (OR = 1.48, 95% CI = 1.39-1.57, p < 0.001). In addition, inverted U-shaped associations were observed between the duration of shift work and health outcomes. These results indicated that shift work was closely related to potential links with poor health outcomes. The findings highlighted the importance of paying attention to the health conditions of shift workers and the necessity of implementing comprehensive protective measures for shift workers to reduce the impact of shift work.

Sleep quality and shift work among Moroccan nurses: A cross-sectional study

BACKGROUND

Sleep is vital for physical and mental health. The nursing profession is often associated with unique challenges when it comes to sleep quality. Nurses are often faced with irregular work schedules, including night shifts and rotations, high-stress levels, and significant job demands that can contribute to sleep problems and hinder their productivity at work. This study aimed to assess sleep quality in Moroccan nurses and to investigate the relationship between sleep quality and shift work.

MATERIALS AND METHODS

This was a cross-sectional study carried out between August 8, 2022 and September 30, 2022 among 260 nurses working day or night shifts in the province of Tétouan, northern Morocco. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality in day and night shift nurses. Data on sociodemographic characteristics and shift work were also collected. Descriptive and inferential statistical analyses were performed. Regression models were used to study the association between participant characteristics and sleep quality.

RESULTS

Among all participants, 60.4% had poor sleep quality. The results of the study revealed that there was no significant association between shift work and sleep quality among nurses in Morocco.

CONCLUSION

Given that the majority of nurses suffer from sleep disorders, an action plan to raise awareness and promote good sleep in this population should be implemented.

Cardiovascular risk in young healthcare professionals: A cross-sectional study

BACKGROUND

In the last years cardiovascular risk has decreased in grown adults and elderly while it seems to be rising among young adults.

OBJECTIVE

to assess the 10-year cardiovascular risk (CVR) in young healthcare professionals at the teaching hospital in Rome, using two scores, and identify possible determinants in order to design and implement preventive strategies.

METHODS

A cross-sectional study was carried out between January 2019 and July 2020. Participants underwent medical history collection, physical examination, and blood tests. CVR was calculated using CUORE and Framingham Risk Scores. A multiple linear regression analysis was conducted having the scores as dependent variables. Diagnostic tests were used for checking model assumptions.

RESULTS

The study was carried out including 525 participants, 58.5% physicians and 32.1% nurses. Multivariate analysis was carried out only for men, since the pp plot for the whole population and for females for the dependent variables showed some evidence of non-normality, and the residual plot shows variance of the residuals was not constant across the range of fitted values. CVR, using the Framingham equation, directly correlated with age (β = 0.260; p < 0.001). Using the CUORE score, qualification as a physician (p < 0.001) is associated with a lower risk of having a CVR, while age (p < 0.001) is directly proportional to this risk.

CONCLUSIONS

Increasing age consistently emerges as a prominent factor, positively influencing both the Framingham risk score and CUORE score, but this association was found only for men. Being a doctor is a protective factor for the CUORE score.

Prevalence of and factors associated with symptoms consistent with a diagnosis of irritable bowel syndrome among resident physicians in standardised training in China: a cross-sectional study

OBJECTIVES

This study aims to investigate the incidence of and factors associated with irritable bowel syndrome (IBS) among resident physicians in standardised training at eight traditional Chinese medicine (TCM) hospitals in China.

DESIGN

A cross-sectional survey was administered to resident physicians in their first to third years of standardised training at eight TCM hospitals.

PARTICIPANTS AND SETTING

A total of 514 resident physicians in standardised training were included.

MEASURES

The questionnaire consisted of two sections, namely: section A collected basic information, and section B included the four-item Perceived Stress Scale (PSS-4), the Patient Health Questionnaire-4 (PHQ-4), the Pittsburgh Sleep Quality Index (PSQI) and the Rome IV criteria for IBS. Univariate and multivariate logistic regression models were constructed to assess the associations of age, sex, body mass index, stress, depression, anxiety, sleep quality and IBS.

RESULTS

Of the included resident doctors, 77.2% were female, 20.4% were obese or underweight and 8.6% had symptoms consistent with a diagnosis of IBS. There were no statistically significant differences in lifestyle factors (night shift work, overtime work or working efficiency during the COVID-19 pandemic) between patients with IBS and participants without IBS (hereafter, non-IBS participants) (p=0.429, p=0.572 or p=0.464, respectively). Notably, compared with non-IBS participants, patients with IBS had significantly higher mean scores on the PSS-4 and PHQ-4 (p=0.028 and p=0.012, respectively); however, there was not a significant difference in PSQI scores between these two groups (p=0.079). Depression symptoms were significantly associated with IBS (unadjusted OR 0.498, 95% CI 0.265 to 0.935, p=0.030).

CONCLUSION

These findings suggest that IBS is common among resident physicians in standardised training. Future studies should investigate emotional distress, especially stress and depression, in the development of prevention or treatment of IBS.

The Cardiac Circadian Clock: Implications for Cardiovascular Disease and its Treatment

Virtually all aspects of physiology fluctuate with respect to the time of day. This is beautifully exemplified by cardiovascular physiology, for which blood pressure and electrophysiology exhibit robust diurnal oscillations. At molecular/biochemical levels (eg, transcription, translation, signaling, metabolism), cardiovascular-relevant tissues (such as the heart) are profoundly different during the day vs the night. Unfortunately, this in turn contributes toward 24-hour rhythms in both risk of adverse event onset (eg, arrhythmias, myocardial infarction) and pathogenesis severity (eg, extent of ischemic damage). Accumulating evidence indicates that cell-autonomous timekeeping mechanisms, termed circadian clocks, temporally govern biological processes known to play critical roles in cardiovascular function/dysfunction. In this paper, a comprehensive review of our current understanding of the cardiomyocyte circadian clock during both health and disease is detailed. Unprecedented basic, translational, and epidemiologic studies support a need to implement chronobiological considerations in strategies designed for both prevention and treatment of cardiovascular disease.

Exploration of genome-wide DNA methylation profiles in night shift workers

The past decades, studies indicated that night shift work is associated with adverse health effects, however, molecular mechanisms underlying these effects are poorly understood. A few previous studies have hypothesized a role for DNA-methylation (DNAm) in this relationship. We performed a cross-sectional epigenome-wide association study, to investigate if night shift work is associated with genome-wide DNAm changes and DNAm-based biological age acceleration, based on previously developed so-called 'epigenetic clocks.' Short term (2-6 years) and intermediate term (10-16 years) night shift workers, along with age and sex matched dayworkers (non-shift workers) were selected from the Lifelines Cohort Study. For genome-wide methylation analysis the Infinium Methylation EPIC array (Ilumina) was used. Linear regression analyses were used to detect differences in methylation at individual CpG-sites associated with night shift work. Pathway analysis was performed based on KEGG pathways and predictions of age acceleration in night shift workers were performed based on four previously developed epigenetic age calculators. Only in women, differences in methylation at individual CpG-sites were observed between night shift workers and non-shift workers. Most of these differentially methylated positions (DMPs) were observed in intermediate term night shift workers. Pathway analysis shows involvement of pathways related to circadian rhythm and cellular senescence. Increased age acceleration was observed only in short-term night shift workers (men and women). This might be indicative of adaptation to night shift work or a so-called healthy worker effect. In conclusion, these results show that DNA methylation changes are associated with night shift work, specifically in women.

Relationship between night shift and sleep problems, risk of metabolic abnormalities of nurses: a 2 years follow-up retrospective analysis in the National Nurse Health Study (NNHS)

BACKGROUND AND PURPOSE

Efforts to improve nurses' physical and mental health are critical to ensuring the safety and quality of the healthcare system. Long-term studies targeting the relevancy of nurses' occupation characteristics with health conditions remain insufficient. This study aimed to examine the relationship between nurses' night shift and sleep problems and metabolic abnormalities risk.

METHODS

This study was a part of the National Nurse Health Study, an ambispective cohort study in China, in 2021. Based on an integration physical examination data system, this study carried out a retrospective analysis of 730 nurses from 2018 to 2020 and combined with a questionnaire survey in 2021. The STROBE guidelines were adopted for reporting.

RESULTS

In the 23 (23.0, 24.0) months follow-up, higher night shift load was associated with more sleep problems such as shortened sleep duration, sleep disorders, poor sleep quality, and sleep deprivation. Moreover, night shift load was associated with chronic diseases risk factors, increasing body mass index and body fat, with more night shift density, increasing the occurrence of low levels of high-density lipoprotein cholesterol, high triglyceride, triglyceride/high-density lipoprotein cholesterol ratio, and serum uric acid.

CONCLUSION

The night shift load has become an occupational health concern, contributing to chronic diseases relevant metabolic risk factors and negative influence on sleep health. Focus on the strategies to improve the sleep quality of nurses undergoing night shift work, optimize work scheduling and ongoing monitor the relevant risk factors are essential to enhance the stability and well-being of the nursing workforce.

CLINICAL TRIALS REGISTRATION INFORMATION

NCT04572347, on October 1, 2020. https://www.

CLINICALTRIALS

gov/ct2/show/NCT04572347.

Circadian Rhythms in Cardiovascular Function: Implications for Cardiac Diseases and Therapeutic Opportunities

Circadian rhythms are internal 24-h intrinsic oscillations that are present in essentially all mammalian cells and can influence numerous biological processes. Cardiac function is known to exhibit a circadian rhythm and is strongly affected by the day/night cycle. Many cardiovascular variables, including heart rate, heart rate variability (HRV), electrocardiogram (ECG) waveforms, endothelial cell function, and blood pressure, demonstrate robust circadian rhythms. Many experiential and clinical studies have highlighted that disruptions in circadian rhythms can ultimately lead to maladaptive cardiac function. Factors that disrupt the circadian rhythm, including shift work, global travel, and sleep disorders, may consequently enhance the risk of cardiovascular diseases. Some cardiac diseases appear to occur at particular times of the day or night; therefore, targeting the disease at particular times of day may improve the clinical outcome. The objective of this review is to unravel the relationship between circadian rhythms and cardiovascular health. By understanding this intricate interplay, we aim to reveal the potential risks of circadian disruption and discuss the emerging therapeutic strategies, specifically those targeting circadian rhythms. In this review, we explore the important role of circadian rhythms in cardiovascular physiology and highlight the role they play in cardiac dysfunction such as ventricular hypertrophy, arrhythmia, diabetes, and myocardial infarction. Finally, we review potential translational treatments aimed at circadian rhythms. These treatments offer an innovative approach to enhancing the existing approaches for managing and treating heart-related conditions, while also opening new avenues for therapeutic development.

Synergistic interaction between long shifts and short rest periods on depression in shift workers: A cross-sectional study from Korea

BACKGROUND

Long shifts and short rest periods (SRP) between shifts are important factors that greatly affect shift workers' health. However, reports on the psychological effects of shift work, such as depression, have been inconsistent. Therefore, this study aimed to investigate the combined effect of long shifts and SRP on depression in shift workers.

METHODS

This cross-sectional study included 3295 shift workers in the sixth Korean Working Conditions Survey. The relative excess risk due to interaction (RERI) was computed to estimate the combined effect of long shifts and SRP on depression.

RESULTS

Depression in shift workers was not significantly associated with long shifts or SRP after adjustment, but the risk was significantly increased when exposed to both factors simultaneously (odds ratio 1.36, 95% confidence interval 1.03-1.79). The RERI between the two factors was statistically significant (p = 0.020), indicating a synergistic interaction with depression. Sensitivity analysis by occupation showed a significant interaction in the combined group of office and service workers (p = 0.034).

CONCLUSIONS

Simultaneous exposure to SRP and long shifts should be avoided when planning shift work schedules or devising health policies for shift workers. Special consideration is needed for healthcare and service workers, who may be particularly vulnerable to negative health impacts due to shift work.

Circadian Disruption in Night Shift Work and Its Association with Chronic Pulmonary Diseases

Globalization and the expansion of essential services over continuous 24 h cycles have necessitated the adaptation of the human workforce to shift-based schedules. Night shift work (NSW) causes a state of desynchrony between the internal circadian machinery and external environmental cues, which can impact inflammatory and metabolic pathways. The discovery of clock genes in the lung has shed light on potential mechanisms of circadian misalignment in chronic pulmonary disease. Here, the current knowledge of circadian clock disruption caused by NSW and its impact on lung inflammation and associated pathophysiology in chronic lung diseases, such as asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and COVID-19, is reviewed. Furthermore, the limitations of the current understanding of circadian disruption and potential future chronotherapeutic advances are discussed.

Nonionizing Electromagnetic Irradiations; Biological Interactions, Human Safety

Human is usually exposed to environmental radiation from natural and man-made sources. Therefore, it is important to investigate the effects of exposure to environmental radiation, partly related to understanding and protecting against the risk of exposure to environmental radiation with beneficial and adverse impacts on human life. The rapid development of technologies causes a dramatic enhancement of radiation in the human environment. In this study, we address the biological effects caused by different fractions of non-ionizing electromagnetic irradiation to humans and describe possible approaches for minimizing adverse health effects initiated by radiation. The main focus was on biological mechanisms initiated by irradiation and represented protection, and safety approaches to prevent health disorders.

The effect of shift work on different hematological parameters among healthcare workers

Shift workers frequently experience alterations in their circadian rhythms, which are correlated with variations in hematological parameters. Changes in blood cells may be related to an individual's health status. Therefore, this study aimed to compare the relationship between shift work and changes in blood cells among a group of healthcare workers in Sri Lanka. A comparative cross-sectional study was conducted among healthcare workers, recruited by a stratified random sampling technique. Socio-demographic data were collected using a structured questionnaire. Venous blood samples were obtained and analyzed for the determination of total and differential blood cell counts. Descriptive statistics were used for the analysis of sociodemographic and hematological parameters. A sample of 37-day workers and 39 shift workers were included in the analysis. The mean ages (years) were not significantly different between the groups (36.8 ± 10.8 vs 39.1 ± 12.0; P = 0.371). Shift employees showed a significantly higher total mean white blood cell count (WBC) of 7548.75 mm-3 compared to day workers' 6869.19 mm-3 (P = 0.027). They also had higher mean absolute counts for all different WBC types (Neutrophils: 3949.2 vs 3557.7  , Lymphocyte: 2756.5 vs 2614.2  , Eosinophil: 317.6 vs 233.4  , Monocytes: 491.63 vs 432.51  , Basophils: 31.68 vs 29.22  ). Shift employees exhibited higher WBC counts than day workers at the same level of work experience. The length of shift work exposure revealed a positive link with neutrophil (r = 0.225  ) and eosinophil counts (r = 0.262  ), whereas these correlations were negative for day workers. Shift workers were associated with higher WBC counts in healthcare workers compared to their day-working counterparts.

The circadian clock and extracellular matrix homeostasis in aging and age-related diseases

The extracellular matrix (ECM) is the noncellular scaffolding component present within all tissues and organs. It provides crucial biochemical and biomechanical cues to instruct cellular behavior and has been shown to be under circadian clock regulation, a highly conserved cell-intrinsic timekeeping mechanism that has evolved with the 24-hour rhythmic environment. Aging is a major risk factor for many diseases, including cancer, fibrosis, and neurodegenerative disorders. Both aging and our modern 24/7 society disrupt circadian rhythms, which could contribute to altered ECM homeostasis. Understanding the daily dynamics of ECM and how this mechanism changes with age will have a profound impact on tissue health, disease prevention, and improving treatments. Maintaining rhythmic oscillations has been proposed as a hallmark of health. On the other hand, many hallmarks of aging turn out to be key regulators of circadian timekeeping mechanisms. In this review, we summarize new work linking the ECM with circadian clocks and tissue aging. We discuss how the changes in the biomechanical and biochemical properties of ECM during aging may contribute to circadian clock dysregulation. We also consider how the dampening of clocks with age could compromise the daily dynamic regulation of ECM homeostasis in matrix-rich tissues. This review aims to encourage new concepts and testable hypotheses about the two-way interactions between circadian clocks and ECM in the context of aging.

Burnout syndrome among nurses at a military medical academy in Serbia

OBJECTIVES

Healthcare workers are the professional group at higher risk of burnout than others. It is the underlying reason for medical errors and the general decrease in quality of patient care and is related to poor patient-healthcare worker relationships. Healthcare workers who work with military personnel have specificities compared to healthcare workers who work only with civilians.

METHODS

A cross-sectional study among 171 nurses at the Military Medical Academy was conducted. The questionnaire consisted of items regarding socio-demographic and socioeconomic characteristics, lifestyle characteristics, workplace environment, workplace stress, strategies of stress management, symptoms and signs of workplace-related stress, and the Serbian version of the Maslach Burnout Inventory.

RESULTS

The prevalence of burnout was 46.2%. The multivariate logistic regression analysis showed that the burnout was associated with stating that they would not choose the same profession again (OR = 4.54, 95% CI: 1.53-14.50) and with not being interested in the work (OR = 4.86, 95% CI: 1.58-14.92).

CONCLUSION

The prevalence of burnout is relatively high among nurses at the Medical Military Academy in Belgrade and is associated with factors in the work environment.

Shift Work and Metabolic Syndrome Updates: A Systematic Review

Shift work can cause circadian cycles disturbances and misaligns the endogenous rhythms. The physiological variables are driven by the circadian system and, its misalignment, can impair the metabolic functions. Thus, the main objective of this study was to evaluate the metabolic alterations as a result of shift work and night work reported in articles published in the last 5 years, using the eligibility criteria both gender and indexed articles in English language. In order to execute this work, we perform a systematic review according to PRISMA guidelines and searched about Chronobiology Disorders and Night Work, both related to metabolism, in Medline, Lilacs, ScienceDirect and Cochrane. Cross-sectional, cohort and experimental studies with low risk of bias were included. We found a total of 132 articles, and, after the selection process, 16 articles remained to be analyzed. It was observed that shift work can cause circadian misalignment and, consequently, some metabolic parameters alterations such as an impaired glycemic control and insulin functioning, cortisol phase release, cholesterol fractions imbalance, changes in morphological indexes and melatonin secretion. There are some limitations, such as heterogenicity in used databases and the 5 years restriction period, because the effects of sleep disturbance may have been reported earlier. In conclusion, we suggest that shift work interferes with the sleep-wake cycle and eating patterns, which cause crucial physiological alterations that, together, can lead to metabolic syndrome.

Association of rotating night shift work, CLOCK, MTNR1A, MTNR1B genes polymorphisms and their interactions with type 2 diabetes among steelworkers: a case-control study

BACKGROUND

The purpose of this study is to investigate the association of rotating night shift work, CLOCK, MTNR1A, MTNR1B genes polymorphisms and their interactions with type 2 diabetes among steelworkers.

METHODS

A case-control study was conducted in the Tangsteel company in Tangshan, China. The sample sizes of the case group and control group were 251 and 451, respectively. The logistic regression, log-linear model and generalized multifactor dimensionality (GMDR) method were used to investigate the interaction between circadian clock gene, melatonin receptor genes and rotating night shift work on type 2 diabetes among steelworkers. Relative excess risk due to interaction (RERI) and attributable proportions (AP) were used to evaluate additive interactions.

RESULTS

Rotating night shift work, current shift status, duration of night shifts, and average frequency of night shifts were associated with an increased risk of type 2 diabetes after adjustment for confounders. Rs1387153 variants in MTNR1B was found to be associated with an increased risk of type 2 diabetes, which was not found between MTNR1A gene rs2119882 locus, CLOCK gene rs1801260 locus and the risk of type 2 diabetes. The association between rotating night shift work and risk of type 2 diabetes appeared to be modified by MTNR1B gene rs1387153 locus (RERI = 0.98, (95% CI, 0.40-1.55); AP = 0.60, (95% CI, 0.07-1.12)). The interaction between MTNR1A gene rs2119882 locus and CLOCK gene rs1801260 locus was associated with the risk of type 2 diabetes (RERI = 1.07, (95% CI, 0.23-1.91); AP = 0.77, (95% CI, 0.36-1.17)). The complex interaction of the MTNR1A-MTNR1B-CLOCK-rotating night shift work model based on the GMDR methods may increase the risk of type 2 diabetes (P = 0.011).

CONCLUSIONS

Rotating night shift work and rs1387153 variants in MTNR1B were associated with an increased risk of type 2 diabetes among steelworkers. The complex interaction of MTNR1A-MTNR1B-CLOCK-rotating night shift work may increase the risk of type 2 diabetes.

The Complex Effects of Light on Metabolism in Humans

Light is an essential part of many life forms. The natural light–dark cycle has been the dominant stimulus for circadian rhythms throughout human evolution. Artificial light has restructured human activity and provided opportunities to extend the day without reliance on natural day–night cycles. The increase in light exposure at unwanted times or a reduced dynamic range of light between the daytime and nighttime has introduced negative consequences for human health. Light exposure is closely linked to sleep–wake regulation, activity and eating patterns, body temperature, and energy metabolism. Disruptions to these areas due to light are linked to metabolic abnormalities such as an increased risk of obesity and diabetes. Research has revealed that various properties of light influence metabolism. This review will highlight the complex role of light in human physiology, with a specific emphasis on metabolic regulation from the perspective of four main properties of light (intensity, duration, timing of exposure, and wavelength). We also discuss the potential influence of the key circadian hormone melatonin on sleep and metabolic physiology. We explore the relationship between light and metabolism through circadian physiology in various populations to understand the optimal use of light to mitigate short and long-term health consequences.

The Effects of Workplace Stressors on Dietary Patterns among Workers at a Private Hospital in Recôncavo of Bahia, Brazil: A Longitudinal Study before and during the COVID-19 Pandemic

Working in a hospital environment is known for presenting unhealthy features that affect the workers' health-features which have currently been intensified due to the COVID-19 pandemic. Hence, this longitudinal study aimed to ascertain the level of job stress before and during the COVID-19 pandemic, how this changed, and its association with the dietary patterns of hospital workers. Data on sociodemographic, occupational, lifestyle, health, anthropometric, dietetic, and occupational stress were collected before and during the pandemic from 218 workers at a private hospital in the Recôncavo of Bahia, Brazil. McNemar's chi-square test was used for comparison purposes, Exploratory Factor Analysis to identify dietary patterns, and Generalized Estimating Equations to evaluate the interested associations. During the pandemic, participants reported increased occupational stress, shift work, and weekly workloads, compared with before the pandemic. Additionally, three dietary patterns were identified before and during the pandemic. No association was observed between changes in occupational stress and dietary pattens. However, COVID-19 infection was related to changes in pattern A (0.647, IC95%0.044;1.241, p = 0.036) and the amount of shift work related to changes in pattern B, (0.612, IC95%0.016;1.207, p = 0.044). These findings support calls to strengthen labour policies to ensure adequate working conditions for hospital workers in the pandemic context.

Prediction of risk of coronary artery disease based on the Framingham risk score in association with shift work among nurses

Objectives. This study aimed to determine the prediction of risk of coronary artery disease (CAD) based on the Framingham risk score (FRS) in association with shift work among nurses.Methods. This cross-sectional and descriptive-analytic study was conducted with nurses working in three hospitals located in Abadan, southwest Iran. The sample size was 120 participants, divided into 60 shift workers and 60 day workers (non-shift workers). Demographic data and medical and occupational history were collected through a checklist and interviews. CAD risk assessment tools used to estimate the 10-year cardiovascular disease (CVD) risk included the FRS. Data were analysed by Mann-Whitney U test, χ² test and one-way analysis of variance (ANOVA) using SPSS version 22.0.Results. There were statistically significant differences between blood pressure (BP), total cholesterol (TC), body mass index (BMI) and shift work (p ≤ 0.001). There was a statistically significant difference between prevalence of CAD risk and shift work based on the FRS (p = 0.04).Conclusion. The study findings showed that shift work is a risk factor for CAD disturbances. Therefore, particular follow-up of shift workers should be recommended for screening and preventing CAD.

Is Being a Lark Healthier for Patients with Type 1 Diabetes Mellitus?

Background  Sleep quality and mood have been evaluated in type 1 diabetic (T1DM) patients, but chronotypes were not studied. Our objectives were to analyze chronotypes, sleep and mood variables and to describe their association with some metabolic variables in this population. Methods  An observational, cross-sectional study was performed. Adults with a diagnosis of T1DM were included. We evaluated chronotypes by the Morningness-Eveningness Questionnaires, sleep quality by Pittsburgh Sleep Quality Index (PSQI), excessive daytime sleepiness by Epworth Sleepiness Scale (ESS), symptoms of depression by Patient Health Questionnaire - 9 (PHQ-9) and emotional well-being by Emotional Well Being Index (IWHO-5). A few metabolic variables were included. Results  Ninety-five patients participated. The mean age was 38 years old (range 18-70). The average body mass index (BMI) was 24.4 Kg/m ² (standard deviation [SD]: 4.6). Out of the total sample, 52.6% were males. The Intermediate chronotype was predominant: n  = 56 (55%). We found poor quality of sleep in 67.4% of the sample, excessive daytime sleepiness in 14.7%, depressive symptoms in 6.3% by PHQ9 and low perception of well-being by IWHO-5 in 16.8%. Evening chronotype scored worse in sleep quality ( p  = 0.05) and had lower well-being ( p  = 0.03) compared with the other chronotypes. Higher MEQ values (morningness) correlated with lower height ( p  = 0.043), lower values in the PSQI ( p  = 0.021); and higher values in emotional well-being ( p  = 0.040). Conclusions  We found that the predominant chronotype in T1DM was the intermediate. Two-thirds reported poor quality of sleep and 14,7% excessive daytime sleepiness. Possible diagnosis of a depressive disorder in 6.3% and poor self-perception of emotional well-being in 16. 8% were observed. The morning chronotype had significant correlation with better sleep quality and higher scores in emotional well-being.

Circadian-mediated regulation of cardiometabolic disorders and aging with time-restricted feeding

Circadian rhythms are present throughout biology, from the molecular level to complex behaviors such as eating and sleeping. They are driven by molecular clocks within cells, and different tissues can have unique rhythms. Circadian disruption can trigger obesity and other common metabolic disorders such as aging, diabetes, and cardiovascular disease, and circadian genes control metabolism. At an organismal level, feeding and fasting rhythms are key drivers of circadian rhythms. This underscores the bidirectional relationship between metabolism and circadian rhythms, and many metabolic disorders have circadian disruption or misalignment. Therefore, studying circadian rhythms may offer new avenues for understanding the etiology and management of obesity. This review describes how circadian rhythm dysregulation is linked with cardiometabolic disorders and how the lifestyle intervention of time-restricted feeding (TRF) regulates them. TRF reinforces feeding-fasting rhythms without reducing caloric intake and ameliorates metabolic disorders such as obesity and associated cardiac dysfunction, along with reducing inflammation. TRF optimizes the expression of genes and pathways related to normal metabolic function, linking metabolism with TRF's benefits and demonstrating the molecular link between metabolic disorders and circadian rhythms. Thus, TRF has tremendous therapeutic potential that could be easily adopted to reduce obesity-linked dysfunction and cardiometabolic disorders.

Occupational Disease in New York State: An Update

An assessment of occupational disease in New York State was undertaken that partially replicated and expanded earlier work from 1987. Utilizing an expanded conception of occupational disease, the assessment used a variety of data sources and methods to provide estimates of mortality and morbidity of occupational disease; workers exposed to specific workplace hazards; disparities in occupational disease among racial/ethnic groups and gender; costs and distribution of costs of occupational disease; and accessible occupational medical resources. Examples of the pathways work may impact health in some of the major health issues of current import including stress-related health conditions; substance use; and overweight/obesity were included. The report contains recommendations for addressing the problem of occupational disease in New York State and advocates for the convening of a statewide group to develop an occupational disease prevention agenda.

Association between Shift Work Schedules and Cardiovascular Events in a Multi-Ethnic Cohort

BACKGROUND

Shift work is known to increase the risk of cardiometabolic diseases and mortality. We investigate the relationship between shift work schedules and cardiometabolic risk factors (smoking, hypertension, and obesity) and their association with cardiometabolic diseases (diabetes and cardiovascular diseases) in a multi-ethnic population from Singapore.

METHODS

2469 participants from the Singapore-based Multi-Ethnic Cohort underwent physical and clinical assessments. Shift work schedules (morning, evening, night, and mixed) were assessed using a validated questionnaire.

RESULTS

Among shift workers, night shift workers had a significantly higher prevalence of smoking (54.5%), diabetes (27.3%), and cardiovascular events (14.1%). Compared to non-shift workers, workers in the night (OR = 2.10, 95%CI: 1.26-3.41) and mixed (OR = 1.74, 95%CI: 1.22-2.48) shift groups were more likely to be current smokers. A significant association between shift duration and smoking (OR = 1.02, 95%CI: 1.00-1.03) was also observed, with longer shift duration (in years) leading to an increase in smoking behavior. No significant associations were found between shift work schedules and hypertension, obesity (BMI), diabetes, and cardiovascular disease, as well as other cardiometabolic risk factors and diseases.

CONCLUSION

This study found that shift schedules and shift duration were most strongly associated with smoking status after covariate adjustments (age, gender, ethnicity, socioeconomic status, and work arrangement), with night and mixed shift types being strongly associated with current smoker status. As smoking is a modifiable risk factor for cardiometabolic disease, employers of shift workers should increase work-based health interventions to control smoking and promote a healthier workforce.

Association between occupational stress, work shift and health outcomes in hospital workers of the Recôncavo of Bahia, Brazil: the impact of COVID-19 pandemic

The aim of this study was to ascertain the level of occupational stress before and during the COVID-19 pandemic, how it changed and its association with health outcomes of hospital workers in the Recôncavo of Bahia, Brazil. A longitudinal study was conducted with 218 hospital workers over 18 years old. A semi-structured questionnaire was used for collecting sociodemographic, occupational, lifestyle, anthropometric and health data. The main exposures were occupational stress, assessed through Job Content Questionnaire and classified according to the Demand-Control Model and reported shift work. Health outcomes considered were nutritional status assessed by BMI, waist circumference and body fat percentage, health self-perception and cardiovascular risk factors. We used McNemar χ2 or Wilcoxon tests to compare the levels of exposure and outcome variables before and during the pandemic, and OR to evaluate associations between changes in occupational stress and shift work with health outcomes. During the pandemic, participants reported increased occupational stress and shift work and lower self-perceived health and had higher BMI and cardiovascular risk factors, compared with before the pandemic. No association was observed between change in occupational stress and health outcomes. However, increased amount of shift work was related to increased BMI in the overall sample (OR 3·79, 95 % CI (1·40, 10·30)) and in health workers (OR 11·56; 95 % CI (2·57, 52·00)). These findings support calls to strengthen labour policies to ensure adequate working conditions for hospital workers in context of the COVID-19 pandemic.

Shift work is significantly and positively associated with dementia: A meta-analysis study

Background

Shift work may disrupt the sleep and wake cycles and negatively affect physical and mental health. Dementia is a neurodegenerative disorder with progressively declining cognition that is receiving increasing attention. Studies on the association between shift work and dementia are rare. Herein, we conducted a meta-analysis to investigate the association between shift work and dementia.

Materials and methods

This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched the PubMed, Embase, and Web of Science databases using a related set of keywords. The inclusion criteria were as follows: (1) adult employees working in a factory, company, or organization; (2) exposure to shift work/non-shift work; and (3) outcome of dementia based on examination or assessment. A meta-analysis using a fixed-effects model was performed. The hazard ratio of dementia was compared between shift workers and non-shift workers.

Results

Five studies were included in the quantitative synthesis, and two were selected for further meta-analysis. A random-effects model showed a modest association between shift work and an increase in dementia cases (pooled hazard ratio = 1.13; 95% confidence interval: 1.04-1.23; p = 0.04). This association also occurred in night workers for more than 1 year.

Conclusion

Shift work and long-term night work were modestly associated with a higher risk of developing dementia. Avoiding long-term night shifts may be effective in reducing dementia risk. Further studies are required to confirm this hypothesis.

Metabolomic profiles in night shift workers: A cross-sectional study on hospital female nurses

Background and aim

Shift work, especially including night shifts, has been found associated with several diseases, including obesity, diabetes, cancers, and cardiovascular, mental, gastrointestinal and sleep disorders. Metabolomics (an omics-based methodology) may shed light on early biological alterations underlying these associations. We thus aimed to evaluate the effect of night shift work (NSW) on serum metabolites in a sample of hospital female nurses.

Methods

We recruited 46 nurses currently working in NSW in Milan (Italy), matched to 51 colleagues not employed in night shifts. Participants filled in a questionnaire on demographics, lifestyle habits, personal and family health history and work, and donated a blood sample. The metabolome was evaluated through a validated targeted approach measuring 188 metabolites. Only metabolites with at least 50% observations above the detection limit were considered, after standardization and log-transformation. Associations between each metabolite and NSW were assessed applying Tobit regression models and Random Forest, a machine-learning algorithm.

Results

When comparing current vs. never night shifters, we observed lower levels of 21 glycerophospholipids and 6 sphingolipids, and higher levels of serotonin (+171.0%, 95%CI: 49.1-392.7), aspartic acid (+155.8%, 95%CI: 40.8-364.7), and taurine (+182.1%, 95%CI: 67.6-374.9). The latter was higher in former vs. never night shifters too (+208.8%, 95%CI: 69.2-463.3). Tobit regression comparing ever (i.e., current + former) and never night shifters returned similar results. Years worked in night shifts did not seem to affect metabolite levels. The Random-Forest algorithm confirmed taurine and aspartic acid among the most important variables in discriminating current vs. never night shifters.

Conclusions

This study, although based on a small sample size, shows altered levels of some metabolites in night shift workers. If confirmed, our results may shed light on early biological alterations that might be related to adverse health effects of NSW.

Obstructive Sleep Apnea, Circadian Clock Disruption, and Metabolic Consequences

Obstructive sleep apnea (OSA) is a chronic disorder characterized by recurrent episodes of apnea and hypopnea during sleep. It is associated with various cardiovascular and metabolic complications, including type 2 diabetes mellitus (T2DM) and obesity. Many pathways can be responsible for T2DM development in OSA patients, e.g., those related to HIF-1 and SIRT1 expression. Moreover, epigenetic mechanisms, such as miRNA181a or miRNA199, are postulated to play a pivotal role in this link. It has been proven that OSA increases the occurrence of circadian clock disruption, which is also a risk factor for metabolic disease development. Circadian clock disruption impairs the metabolism of glucose, lipids, and the secretion of bile acids. Therefore, OSA-induced circadian clock disruption may be a potential, complex, underlying pathway involved in developing and exacerbating metabolic diseases among OSA patients. The current paper summarizes the available information pertaining to the relationship between OSA and circadian clock disruption in the context of potential mechanisms leading to metabolic disorders.