Sleep quality and methylation status of core circadian rhythm genes among nurses and midwives

Impact of sleep disturbance in shift workers on hippocampal volume and psychomotor speed

STUDY OBJECTIVES

Shift work interferes with circadian rhythms, affecting sleep quality and cognitive function. Poor sleep quality in shift worker (SW)s can impair psychomotor performance due to fatigue and sleepiness, increasing the risk of errors, accidents, and reduced productivity. Given the potential for atrophic changes in the hippocampus due to sleep disturbances, our study investigates how poor sleep quality correlates with hippocampal structural alterations and impacts psychomotor performance among SWs.

METHODS

We recruited 100 SWs, classifying them based on sleep quality into two groups: good sleep-SW group (n = 59) and poor sleep-SW group (n = 41). Sleep quality was assessed using both 7-day actigraphy for sleep efficiency and the Pittsburgh Sleep Quality Index. A control group of 106 non-SWs without sleep problems (non-SW group) was also included for comparison. The outcome measures were psychomotor speed and hippocampal volumes, both total and by subfield.

RESULTS

The poor sleep-SW group showed significantly smaller hippocampal volumes than both the good sleep-SW group (p < .001) and the non-SW group (p = .003). Longer shift work years correlated with greater reductions in hippocampal volume in this group (r = -0.42, p = .009), unlike in the good sleep-SW group (r = 0.08, p = .541). Furthermore, they demonstrated declines in psychomotor speed relative to the non-SW group (p = .006), which correlated with smaller hippocampal volumes (r = 0.37, p = .020).

CONCLUSIONS

SWs with poor sleep quality exhibit significant hippocampal volume reductions and psychomotor speed decline, underscoring the importance of early intervention and support for sleep issues in this population.

The interaction between mental resilience and insomnia disorder on negative emotions in nurses in Guangdong Province, China

Objective

To investigate the current status of psychological resilience, insomnia and negative emotions among nurses in Guangdong Province, China. And to explore the effects of the interaction between psychological resilience and insomnia on negative emotions.

Methods

A cross-sectional survey method was used to select 1874 nurses in Guangdong Province from February 2023 to April 2023 for the survey. The Chinese version of the Psychological Resilience Scale (PRS), Insomnia Severity Index (ISI), Depression Anxiety and Stress Scale-21(DASS-21)were used in this study. We use SPSS 26.0 for statistical analysis. A simple effect analysis was established to analyze the association between psychological resilience, insomnia and negative emotions by using psychological resilience, insomnia and the interaction term.

Results

The overall PRS and ISI scores were (59.79 ± 17.29) and (9.83 ± 5.97). The scores of DASS-21 each dimension were (8.19 ± 9.02) for depression emotion,(7.93 ± 7.66) for anxiety emotion and (10.58 ± 9.77) for stress emotion. The results of the interaction effect analysis indicated that psychological resilience and insomnia exhibited statistically significant differences in the between-subjects effect test for depression emotion (r2 = 0.136, P<0.01), anxiety emotion (r2 = 0.127, P<0.01), and stress emotion (r2 = 0.142, P<0.01).

Conclusion

The nurses exhibited moderate levels of psychological resilience. Most of them have varying degrees of insomnia, with majority being classified as mild insomnia. Additionally, they demonstrated varying degrees of negative emotions. There was a negative correlation between psychological resilience and insomnia. Psychological resilience was negatively correlated with depression, anxiety and stress emotions. Insomnia was positively correlated with depression, anxiety and stress emotions. Furthermore, the interaction between psychological resilience and insomnia had an effect on all three dimensions of negative emotions. Consequently, hospital administrators may implement efficacious intervention strategies such as cognitive behavioral therapy and improving workplace climate in a timely manner according to the different psychological tolerance and severity of insomnia of nurses in order to reduce the occurrence of negative emotions among nurses and improve their mental health.

Prospective study of the association between chronotypes and depressive symptoms in Chinese university students: Moderating effects of PER1 gene DNA methylation

Most studies have shown a link between chronotypes and mental health and have identified evening chronotypes (E-types) as a potential risk for depressive symptoms. However, the mechanisms behind this association remain unknown. Abnormal expression of the PER1 gene was not only associated with circadian rhythm disturbance, but also closely related to mental illness. Therefore, this study aimed to examine the association of chronotype with depressive symptoms, and further explore the moderating effects of the PER1 gene DNA methylation on chronotypes and depressive symptoms in Chinese university students. In a stratified cluster sampling design, chronotype and depressive symptoms were assessed in 1 042 university students from 2 universities in a two-year prospective survey from April 2019 to October 2020. The survey was conducted once every 6 months, corresponding to the time points in April 2019 (T0), October 2019 (T1), April 2020 (T2), and October 2020 (T3). At T0, the Morning and Evening Questionnaire 5 (MEQ-5) was adopted to assess chronotype. At T0-T3, the Patient Health Questionnaire 9 (PHQ-9) was adopted to investigate depressive symptoms. Meanwhile, at T0, participants were subjected to a health check-up trip in the hospital, and blood samples were taken from the students to measure the PER1 gene DNA methylation levels. Binary logistic regression was used to analyze the association of chronotypes with depressive symptoms. The depression/total depression group was coded as 1, while the remaining participants was defined as one group, and was coded as 0. The PROCESS plug-in of SPSS software was used to analyze the moderating effects of PER1 gene DNA methylation on the association of chronotype with depressive symptoms. After adjusting for covariates, the results indicated that T0 E-types were positively correlated with T0-T3 depression/total depression in female university students. Furthermore, the PER1 gene DNA methylation has negative moderating effects between T0 chronotype and T3 depressive symptoms and has a sex difference. This study can provide more favorable scientific value for the prevention and control of depression in university students.

The race-based stress reduction intervention (RiSE) study on African American women in NYC and Chicago: Design and methods for complex genomic analysis

RiSE study aims to evaluate a race-based stress-reduction intervention as an effective strategy to improve coping and decrease stress-related symptoms, inflammatory burden, and modify DNA methylation of stress response-related genes in older AA women. This article will describe genomic analytic methods to be utilized in this longitudinal, randomized clinical trial of older adult AA women in Chicago and NYC that examines the effect of the RiSE intervention on DNAm pre- and post-intervention, and its overall influence on inflammatory burden. Salivary DNAm will be measured at baseline and 6 months following the intervention, using the Oragene-DNA kit. Measures of perceived stress, depressive symptoms, fatigue, sleep, inflammatory burden, and coping strategies will be assessed at 4 time points including at baseline, 4 weeks, 8 weeks, and 6 months. Genomic data analysis will include the use of pre-processed and quality-controlled methylation data expressed as beta (β) values. Association analyses will be performed to detect differentially methylated sites on the targeted candidate genes between the intervention and non-intervention groups using the Δβ (changes in methylation) with adjustment for age, health behaviors, early life adversity, hybridization batch, and top principal components of the probes as covariates. To account for multiple testing, we will use FDR adjustment with a corrected p-value of <0.05 regarded as statistically significant. To assess the relationship between inflammatory burden and Δβ among the study samples, we will repeat association analyses with the inclusion of individual inflammation protein measures. ANCOVA will be used because it is more statistically powerful to detect differences.

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.

Early-to-mid pregnancy sleep and circadian markers in relation to birth outcomes: An epigenetics pilot study

Maternal sleep and circadian health during pregnancy are emerging as important predictors of pregnancy outcomes, but examination of potential epigenetic mechanisms is rare. We investigated links between maternal leukocyte DNA methylation of circadian genes and birth outcomes within a pregnancy cohort. Women (n = 96) completed a questionnaire and provided a blood sample at least once during early-to-mid pregnancy (average gestation weeks = 14.2). Leukocyte DNA was isolated and DNA methylation (average percent of methylation) at multiple CpG sites within BMAL1, PER1, and MTNR1B genes were quantified by pyrosequencing. Birth outcomes including gestational age at delivery, birthweight, and head circumference were abstracted from medical charts. Linear regression analyses were run between each CpG site with birth outcomes, adjusting for important confounders. Sleep duration and timing were assessed as secondary exposures. Higher methylation of a CpG site in PER1 was associated with smaller log-transformed head circumference (β=-0.02 with 95% CI -0.02 to 0.01; P, trend = 0.04). Higher methylation of MTNR1B (averaged across sites) was associated with lower log-transformed birthweight (-0.08 with 95% CI -0.16 to -0.01; P, trend = 0.0495). In addition, longer sleep duration was associated with higher birthweight (0.10 with 95% CI 0.02 to 0.18 comparing > 9 h to < 8 h; P, trend = 0.04). This pilot investigation revealed that higher methylation of PER1 and MTNR1B genes, and sleep duration measured in early-to-mid pregnancy were related to birth outcomes.

Association between night shift work and methylation of a subset of immune-related genes

Introduction

Night shift (NS) work has been associated with an increased risk of different conditions characterized by altered inflammatory and immune responses, such as cardio-metabolic and infectious diseases, cancer, and obesity. Epigenetic modifications, such as DNA methylation, might mirror alterations in biological processes that are influenced by NS work.

Methods

The present study was conducted on 94 healthy female workers with different working schedules and aimed at identifying whether NS was associated with plasmatic concentrations of the inflammatory proteins NLRP3 and TNF-alpha, as well as with DNA methylation levels of ten human endogenous retroviral (HERV) sequences, and nine genes selected for their role in immune and inflammatory processes. We also explored the possible role of the body mass index (BMI) as an additional susceptibility factor that might influence the effects of NS work on the tested epigenetic modifications.

Results and discussion

We observed a positive association between NS and NLRP3 levels (p-value 0.0379). Moreover, NS workers retained different methylation levels for ERVFRD-1 (p-value = 0.0274), HERV-L (p-value = 0.0377), and HERV-P (p-value = 0.0140) elements, and for BIRC2 (p-value = 0.0460), FLRT3 (p-value = 0.0422), MIG6 (p-value = 0.0085), and SIRT1 (p-value = 0.0497) genes. We also observed that the BMI modified the relationship between NS and the methylation of ERVE, HERV-L, and ERVW-1 elements. Overall, our results suggest that HERV methylation could pose as a promising biomolecular sensor to monitor not only the effect of NS work but also the cumulative effect of multiple stressors.

Association of plant-based diet index with inflammatory markers and sleep quality in overweight and obese female adults: A cross-sectional study

BACKGROUND

Inflammation and sleep disturbances increase the risk of multiple diseases, including cardiovascular disease, type 2 diabetes and dementia. Since diet plays a significant role in inflammatory responses and sleep quality, this study aimed to investigate the association of a plant-based diet index (PDI) with sleep quality and inflammatory markers in overweight and obese women.

METHODS

390 overweight and obese women aged 18-48 years participated in this cross-sectional study. A validated food frequency questionnaire (FFQ) was used to create an overall PDI, healthful plant-based diet index (hPDI) and unhealthful plant-based diet index (uPDI). Sleep quality was assessed by Pittsburgh Sleep Quality Index (PSQI). Higher scores on the PSQI were indicative of poor sleep. Anthropometric measurements and serum concentrations of high-sensitivity C-reactive protein (hs-CRP), interleukin 1 beta (IL-1β) and transforming growth factor-beta (TGF-β) were evaluated. Linear regression models were used to determine the association between exposure and outcomes.

RESULTS

After taking potential confounders into account, we found a significant inverse association between adherence to hPDI and hs-CRP (β = -0.14, 95% confidence interval [CI]: -0.22,0.06, P = .001) and a significant positive association between uPDI and hs-CRP (β = 0.13, 95% CI: 0.05,0.21, P = .001). Overall, PDI was significantly associated with TGF-β (β = 2.04, 95% CI: 0.54,3.55, P = .008). No association was detected between PDI indices and IL-1β. Higher adherence to uPDI was significantly associated with higher PSQI score (lower sleep quality) (β= 0.20, 95% CI:0.007,0.40, P = .04). A significant positive association was found between TGF-β (β = 0.05, 95% CI:0.005,0.10, P = .03) and hs-CRP (β = 0.32, 95% CI:0.02,0.62, P = .03) with PSQI.

CONCLUSION

Our findings indicated a significant association between adherence to a plant-based diet with inflammation and sleep quality in obese and overweight females. WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Sleep is an essential part of life, and sleep quality has a significant impact on individual well-being and performance. There is a bidirectional relationship between disturbed sleep and elevated levels of inflammatory markers. Diet plays a major part in sleep quality and its related health consequences. Plant-based diets are associated with lower risk of chronic diseases such as coronary artery disease (CAD), type 2 diabetes, obesity and reduced level of inflammation. WHAT DOES THIS ARTICLE ADD?: Adherence to a healthful plant-based diet is associated with lower level of hs-CRP, while adherence to an unhealthful plant-based diet is associated with higher concentrations of hs-CRP. Adherence to an unhealthful plant-based diet is associated with lower sleep quality.

Influence of rotating shifts and fixed night shifts on sleep quality of nurses of different ages: a systematic literature review and meta-analysis

The objective of this study was to understand the influence of rotating shifts and fixed night shifts on the sleep quality of nurses using a systematic literature review and meta-analysis and to determine whether the sleep quality of nurses working rotating shifts or fixed night shifts differs from that of nurses working fixed day shifts. We conducted a meta-analysis on literature that had used the Pittsburgh Sleep Quality Index (PSQI) to gauge sleep quality and had been published between 2000 and 2020 in the Cochrane Library, CINAHL, MEDLINE, and PubMed databases. This study was conducted in accordance with PRISMA, and the quality of the literature was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Analytical Cross Sectional Studies. CMA 3.0 was employed for data analysis, and meta-regression analysis was conducted to examine the differences between the PSQI scores of nurses working fixed day shifts and those working rotating shifts or fixed night shifts. Following assessment, a total of 29 papers (34 items of data) were analyzed. The papers included a total of 3,935 nurses who worked fixed day shifts, 3,777 nurses who worked rotating shifts, and 1,559 nurses who worked fixed night shifts. Our subgroup analysis indicated that the sleep quality of nurses working rotating shifts was poorer than the sleep quality of nurses working fixed day shifts; the standardized mean difference (SMD) was 0.38 (95% CI: 0.24-0.52, p< .001), and the meta-regression analysis found that the difference in sleep quality between nurses over 40 years old working rotating shifts and those working fixed day shifts was significantly smaller than the difference in sleep quality between nurses 40 years old or younger working rotating shifts and those working fixed day shifts (β = -0.368, p= .011). The sleep quality of nurses working fixed night shifts was also poorer than the sleep quality of nurses working fixed day shifts; the SMD was 0.58 (95% CI: 0.38-0.78, p< .001), and the meta-regression analysis revealed that the difference in sleep quality between nurses over 40 years old working fixed night shifts and those working fixed day shifts was not significantly different from the difference in sleep quality between nurses 40 years old or younger working fixed night shifts and those working fixed day shifts (β = -0.118, p= .608). This meta-analysis found that both nurses working rotating shifts and those working fixed night shifts had poorer sleep quality than those working fixed day shifts and that age influenced the difference in sleep quality only between nurses working rotating shifts and those working fixed day shifts; the difference in sleep quality between nurses 40 years old or younger working rotating shifts and those working fixed day shifts was greater than the difference in sleep quality between nurses over 40 years old working rotating shifts and those working fixed day shifts.

Prevalence of Poor Sleep Quality in Nursing Staff: A Meta-Analysis of Observational Studies

Objective: Poor sleep quality is common in nursing staff. This meta-analysis aimed to examine the pooled prevalence of poor sleep quality in nursing staff. Methods: A systematic search in PubMed, EMBASE, PsycINFO, and Web of Science databases was performed. Studies that reported sleep quality measured by the Pittsburgh Sleep Quality Index (PSQI) were synthesized using a random-effects model. Results: Fifty-three studies were analyzed. The pooled prevalence of poor sleep quality was 61.0% (95% CI: 55.8-66.1%). The pooled total PSQI score was 7.13 ± 0.18 (95% CI: 6.78-7.50). The pooled component scores were 1.47 ± 0.20 (95% CI of mean score: 1.08-1.85) in sleep latency, 0.91 ± 0.15 (95% CI of mean score: 0.61-1.21) in sleep duration, 1.59 ± 0.13 (95% CI of mean score: 1.35-1.84) in overall sleep disturbances, 0.33 ± 0.18 (95% CI of mean score: 0-0.67) in sleeping medication, 1.21 ± 1.20 (95% CI of mean score: 0.83-1.60) in daytime dysfunction, 1.39 ± 0.14 (95% CI of mean score: 1.11-1.67) in subjective sleep quality, and 0.66 ± 0.11 (95% CI of mean score: 0.44-0.87) in habitual sleep efficiency. Subgroup and meta-regression analyses found that PSQI cutoff values, mean age, body mass index (BMI), sample size, study quality, and work experience moderated the prevalence of poor sleep quality. Conclusions: Poor sleep quality appears to be common in nursing staff. Considering its negative impact on health, effective measures should be taken to improve poor sleep quality in this population. Longitudinal studies should be conducted to examine the contributing factors of nurses' poor sleep quality.

Adolescent sleep timing and dietary patterns in relation to DNA methylation of core circadian genes: a pilot study of Mexican youth

Mistimed sleep/wake and eating patterns put shift workers at increased risk for cardiometabolic disease, and epigenetic modification of circadian genes has been proposed as a mechanism. Although not as extreme as shift workers, adolescents often have delayed sleep timing and irregular eating patterns. The aim was to assess whether sleep midpoints - median of bed and wake time - and dietary patterns in adolescents were associated with DNA methylation of circadian genes. The study population included 142 Mexican youth (average age of 14.0 (SD = 2.0) years, 49% male). Average sleep midpoint over weekdays was estimated with actigraphy. Diet was assessed with a semi-quantitative food frequency questionnaire, and three dietary patterns were derived from principal component analysis, a Plant-based & lean proteins pattern, a Meat & starchy pattern, and an Eggs, milk & refined grain pattern. DNA methylation was quantified in blood leukocytes with the Infinium MethylationEPIC BeadChip, and data from 548 CpG sites within 12 circadian genes were examined. Linear regression analyses, adjusted for sex, age, and % monocytes, showed that later sleep timing was associated with higher DNA methylation of several circadian genes, notably with RORB, PER1, CRY2, and NR1D1. Each of the dietary patterns examined was also related to circadian gene DNA methylation, but the Eggs, milk & refined grain pattern ('breakfast' pattern) had the clearest evidence of relationships with circadian genes, with inverse associations (lower DNA methylation) across all 12 genes. Findings suggest that timing-related sleep and eating behaviours among adolescents could result in epigenetic modification of clock genes.

Epigenetic Regulation of Circadian Rhythm and Its Possible Role in Diabetes Mellitus

This review aims to summarize the knowledge about the relationship between circadian rhythms and their influence on the development of type 2 diabetes mellitus (T2DM) and metabolic syndrome. Circadian rhythms are controlled by internal molecular feedback loops that synchronize the organism with the external environment. These loops are affected by genetic and epigenetic factors. Genetic factors include polymorphisms and mutations of circadian genes. The expression of circadian genes is regulated by epigenetic mechanisms that change from prenatal development to old age. Epigenetic modifications are influenced by the external environment. Most of these modifications are affected by our own life style. Irregular circadian rhythm and low quality of sleep have been shown to increase the risk of developing T2DM and other metabolic disorders. Here, we attempt to provide a wide description of mutual relationships between epigenetic regulation, circadian rhythm, aging process and highlight new evidences that show possible therapeutic advance in the field of chrono-medicine which will be more important in the upcoming years.

Acute and Chronic Molecular Signatures and Associated Symptoms of Blast Exposure in Military Breachers

Injuries from exposure to explosions rose dramatically during the Iraq and Afghanistan wars, which motivated investigations of blast-related neurotrauma and operational breaching. In this study, military “breachers” were exposed to controlled, low-level blast during a 10-day explosive breaching course. Using an omics approach, we assessed epigenetic, transcriptional, and inflammatory profile changes in blood from operational breaching trainees, with varying levels of lifetime blast exposure, along with daily self-reported symptoms (with tinnitus, headaches, and sleep disturbances as the most frequently reported). Although acute exposure to blast did not confer epigenetic changes, specifically in DNA methylation, differentially methylated regions (DMRs) with coordinated gene expression changes associated with lifetime cumulative blast exposures were identified. The accumulative effect of blast showed increased methylation of PAX8 antisense transcript with coordinated repression of gene expression, which has been associated with sleep disturbance. DNA methylation analyses conducted in conjunction with reported symptoms of tinnitus in the low versus high blast incidents groups identified DMRS in KCNE1 and CYP2E1 genes. KCNE1 and CYP2E1 showed the expected inverse correlation between DNA methylation and gene expression, which have been previously implicated in noise-related hearing loss. Although no significant transcriptional changes were observed in samples obtained at the onset of the training course relative to chronic cumulative blast, we identified a large number of transcriptional perturbations acutely pre- versus post-blast exposure. Acutely, 67 robustly differentially expressed genes (fold change ≥1.5), including UFC1 and YOD1 ubiquitin-related proteins, were identified. Inflammatory analyses of cytokines and chemokines revealed dysregulation of MCP-1, GCSF, HGF, MCSF, and RANTES acutely after blast exposure. These data show the importance of an omics approach, revealing that transcriptional and inflammatory biomarkers capture acute low-level blast overpressure exposure, whereas DNA methylation marks encapsulate chronic long-term symptoms.

Molecular and epigenetic markers as promising tools to quantify the effect of occupational exposures and the risk of developing non-communicable diseases

Non-communicable diseases (NCDs) are chronic diseases that are by far the leading cause of death in the world. Many occupational hazards, together with social, economic and demographic factors, have been associated to NCDs development. Genetic susceptibility or environmental exposures alone are not usually sufficient to explain the pathogenesis of NCDs, but can be integrated in a more complex scenario that can result in pathological phenotypes. Epigenetics is a crucial component of this scenario, as its changes are related to specific exposures, therefore potentially able to display the effects of environment on the genome, filling the gap between genetic asset and environment in explaining disease development. To date, the most promising biomarkers have been assessed in occupational cohorts as well as in case/control studies and include DNA methylation, histone modifications, microRNA expression, extracellular vesicles, telomere length, and mitochondrial alterations.