Effect of shift work on hypertension: cross sectional study

The Impact of Night Work on the Sleep and Health of Medical Staff-A Review of the Latest Scientific Reports

Introduction: Employees working in shifts are exposed to many threats affecting their health, quality of life and safety at work. Those who perform their work only at night are particularly vulnerable. The purpose of the review is to identify risks to the health, quality of life and sleep of shift health workers. Method: A systematic review (SR) was used in the analysis. Electronic databases were searched. The search was limited to the latest studies published in the last five years: 2019-2023. Results: Finally, 36 articles were included in the review. Most authors have shown a link between sleep disturbance or its quality and shift work/night work. Moreover, a three-shift schedule was the most significant factor for poorer subjective sleep quality when compared to other work schedules. Furthermore, many authors have shown a link between shift/night work and health problems, which include cardiometabolic risk, glucose intolerance, breast cancer and immune vulnerability. Conclusions: The research results clearly show a significant impact of night work on the increased risk of sleep disorders and health disturbance. Healthcare workers should be aware of the risks associated with night work in order to take measures preventing sleep/health problems. Shift/night workers should have the opportunity to be screened for disorders linked with their work.

The interrelationships between sleep regularity, obstructive sleep apnea, and hypertension in a middle-aged community population

STUDY OBJECTIVES

Little is known about the interrelationships between sleep regularity, obstructive sleep apnea (OSA) and important health markers. This study examined whether irregular sleep is associated with OSA and hypertension, and if this modifies the known association between OSA and hypertension.

METHODS

Six hundred and two adults (age mean(SD) = 56.96(5.51) years, female = 60%) from the Raine Study who were not evening or night shift workers were assessed for OSA (in-laboratory polysomnography; apnea-hypopnea index ≥ 15 events/hour), hypertension (doctor diagnosed, or systolic blood pressure ≥140 mmHg and/or diastolic ≥90 mmHg) and sleep (wrist actigraphy for ≥5 days). A sleep regularity index (SRI) was determined from actigraphy. Participants were categorized by tertiles as severely irregular, mildly irregular, or regular sleepers. Logistic regression models examined the interrelationships between SRI, OSA and hypertension. Covariates included age, sex, body mass index, actigraphy sleep duration, insomnia, depression, activity, alcohol, smoking, and antihypertensive medication.

RESULTS

Compared to regular sleepers, participants with mildly irregular (OR 1.97, 95% confidence intervals [CI] 1.20 to 3.27) and severely irregular (OR 2.06, 95% CI: 1.25 to 3.42) sleep had greater odds of OSA. Compared to those with no OSA and regular sleep, OSA and severely irregular sleep combined had the highest odds of hypertension (OR 2.34 95% CI: 1.07 to 5.12; p for interaction = 0.02) while those with OSA and regular/mildly irregular sleep were not at increased risk (p for interaction = 0.20).

CONCLUSIONS

Sleep irregularity may be an important modifiable target for hypertension among those with OSA.

Pressure Building Against the Clock: The Impact of Circadian Misalignment on Blood Pressure

PURPOSE OF REVIEW

Misalignment between the endogenous biological timing system and behavioral activities (i.e., sleep/wake, eating, activity) contributes to adverse cardiovascular health. In this review, we discuss the effects of recurring circadian misalignment on blood pressure regulation and the implications for hypertension development. Additionally, we highlight emerging therapeutic approaches designed to mitigate the negative cardiovascular consequences elicited by circadian disruption.

RECENT FINDINGS

Circadian misalignment elicited by work schedules that require individuals to be awake during the biological night (i.e., shift work) alters 24-h blood pressure rhythms. Mechanistically, circadian misalignment appears to alter blood pressure via changes in autonomic nervous system balance, variations to sodium retention, dysregulation of endothelial vasodilatory responsiveness, and activation of proinflammatory mechanisms. Recurring circadian misalignment produced by a mismatch in sleep timing on free days vs. work days (i.e., social jetlag) appears to have no direct effects on prevailing blood pressure levels in healthy adults; though, circadian disruptions resulting from social jetlag may increase the risk of hypertension through enhanced sympathetic activation and/or obesity. Furthermore, social jetlag assessment may be a useful metric in shift work populations where the magnitude of circadian misalignment may be greater than in the general population. Circadian misalignment promotes unfavorable changes to 24-h blood pressure rhythms, most notably in shift working populations. While light therapy, melatonin supplementation, and the timing of drug administration may improve cardiovascular outcomes, interventions designed to target the effects of circadian misalignment on blood pressure regulation are warranted.

Arterial hypertension in rotating shift workers: The role of hypertriglyceridemic waist and hypertriglyceridemic waist-to-height ratio phenotypes

OBJECTIVE

To examine the association of arterial hypertension and the hypertriglyceridemic waist phenotype (HWP) and hypertriglyceridemic waist-to-height phenotype (HWHP).

METHODOLOGY

This cross-sectional study was conducted with 1422 male rotating shift workers in Brazil. The HWP was defined as having a waist circumference ≥94 cm and serum triglycerides ≥150 mg/dL, whereas the HWHP was determined by having a waist-to-height ratio ≥0.5 and serum triglycerides ≥150 mg/dL. To provide a characterization of the sample, data were presented in both absolute and relative values, and Pearson's chi-square test was employed. To investigate the potential association between arterial hypertension and the presence of HWP or HWHP, multivariate logistic regression was conducted, accounting for sociodemographic, behavioral, and clinical variables. Furthermore, we conducted a stratified multivariate logistic regression analysis, considering the duration of shift work, to assess whether the results remained consistent depending on the length of work experience in shifts.

RESULTS

A noteworthy association was observed between arterial hypertension and both HWP and HWHP, with HWHP exhibiting a stronger association with the disease. Furthermore, a positive association between arterial hypertension and these phenotypes was identified in workers with five or more years of shift work.

CONCLUSION

We recommend the utilization of HWHP as a screening tool, as it indicates a stronger association with arterial hypertension compared to HWP. Additionally, the duration of time spent working in shifts emerged as a significant factor influencing the presence of these phenotypes.

Circadian Rhythms Disrupted by Light at Night and Mistimed Food Intake Alter Hormonal Rhythms and Metabolism

Availability of artificial light and light-emitting devices have altered human temporal life, allowing 24-hour healthcare, commerce and production, and expanding social life around the clock. However, physiology and behavior that evolved in the context of 24 h solar days are frequently perturbed by exposure to artificial light at night. This is particularly salient in the context of circadian rhythms, the result of endogenous biological clocks with a rhythm of ~24 h. Circadian rhythms govern the temporal features of physiology and behavior, and are set to precisely 24 h primarily by exposure to light during the solar day, though other factors, such as the timing of meals, can also affect circadian rhythms. Circadian rhythms are significantly affected by night shift work because of exposure to nocturnal light, electronic devices, and shifts in the timing of meals. Night shift workers are at increased risk for metabolic disorder, as well as several types of cancer. Others who are exposed to artificial light at night or late mealtimes also show disrupted circadian rhythms and increased metabolic and cardiac disorders. It is imperative to understand how disrupted circadian rhythms alter metabolic function to develop strategies to mitigate their negative effects. In this review, we provide an introduction to circadian rhythms, physiological regulation of homeostasis by the suprachiasmatic nucleus (SCN), and SCN-mediated hormones that display circadian rhythms, including melatonin and glucocorticoids. Next, we discuss circadian-gated physiological processes including sleep and food intake, followed by types of disrupted circadian rhythms and how modern lighting disrupts molecular clock rhythms. Lastly, we identify how disruptions to hormones and metabolism can increase susceptibility to metabolic syndrome and risk for cardiovascular diseases, and discuss various strategies to mitigate the harmful consequences associated with disrupted circadian rhythms on human health.

Association Between Night Shift and Hypertension: A Cross-Sectional Study in Chinese Adults

OBJECTIVE

The purpose of this study was to explore the effect of night-shift work on the risk of hypertension for improving workers' health.

METHODS

A total of 10,038 Chinese participants were constituted in the cross-sectional study. Logistic regression and restricted cubic spline were used to estimate the effect of night shift on hypertension.

RESULTS

There were higher odds of having hypertension in any night-shift workers (odds ratio [OR], 1.16 [95% confidence interval, 1.03-1.30]) when compared with day workers. Having 5 to 10 night shifts per month were significantly more likely to be hypertensive (OR, 1.19 [95% confidence interval, 1.03-1.38]). The OR for hypertension increased as the number of night shifts increased as the result of the restricted cubic spline.

CONCLUSIONS

Our results support the hypothesis that night shift is associated with an elevated risk of hypertension.

Knowledge of Primary Care Patients Living in the Urban Areas about Risk Factors of Arterial Hypertension

Arterial hypertension (AH), one of the most common diseases of civilization, is an independent risk factor for cardiovascular morbidity and mortality. This disease is the second, after lipid disorders, the most common cardiovascular risk factor and a significant cause of premature death. In Poland, one in three adults (approximately 11 million people) suffers from it. The aim of our survey was to determine patients’ knowledge of the factors (e.g., age, smoking cigarettes, drinking coffee, shift work) that may influence the development of hypertension. The survey was conducted among 205 adult primary care patients living in urban areas. There was a high correlation between patients’ education and risk factors of AH, such: as excess salt in the diet (p = 0.038), smoking electronic cigarettes (p = 0.005), moderate alcohol consumption (p = 0.028), moderate daily physical activity (p = 0.011), female and male sex (p = 0.032 and p = 0.012), air pollution (p < 0.001) and others. In addition, a statistically significant factor shaping patients’ attitudes toward hypertension prevention was the correlation between the respondents’ education and their parents’ prevalence of hypertension (p = 0.40). This study increases the knowledge of patients’ awareness of hypertension. It may serve as guidance for primary care providers to pay special attention to environmental interviews with patients and the patient’s family history for the prevention of hypertension incidence.

The effect of blood cadmium levels on hypertension in male firefighters in a metropolitan city

Background

This study investigated the effect of dispatch frequency on blood cadmium levels and the effect of blood cadmium levels on hypertension in male firefighters in a metropolitan city.

Methods

We conducted a retrospective longitudinal study of male firefighters who completed the regular health checkups, including a health examination survey and blood cadmium measurements. We followed them for 3 years. To investigate the effect of dispatch frequency on blood cadmium levels and the effect of blood cadmium levels on hypertension, we estimated the short-term (model 1) and long-term (model 2) effects of exposure and hypothesized a reversed causal pathway model (model 3) for sensitivity analysis. Sequential conditional mean models were fitted using generalized estimating equations, and the odds ratios (ORs) and the respective 95% confidence intervals (CIs) were calculated for hypertension for log-transformed (base 2) blood cadmium levels and quartiles.

Results

Using the lowest category of dispatch frequency as a reference, we observed that the highest category showed an increase in blood cadmium levels of 1.879 (95% CI: 0.673, 3.086) μg/dL and 0.708 (95% CI: 0.023, 1.394) μg/dL in models 2 and 3, respectively. In addition, we observed that doubling the blood cadmium level significantly increased the odds of hypertension in model 1 (OR: 1.772; 95% CI: 1.046, 3.003) and model 3 (OR: 4.288; 95% CI: 1.110, 16.554). Using the lowest quartile of blood cadmium levels as a reference, the highest quartile showed increased odds of hypertension in model 1 (OR: 2.968; 95% CI: 1.121, 7.861) and model 3 (OR: 33.468; 95% CI: 1.881, 595.500).

Conclusions

We found that dispatch frequency may affect blood cadmium levels in male firefighters, and high blood cadmium levels may influence hypertension in a dose-response manner.

Shift work and cardiovascular strain on working and non-working days

BACKGROUND

Shift work is often associated with adverse effects on cardiovascular health of employees. Only a few studies address the strain of shift and day workers on non-working days compared to working days.

AIMS

This study aims to determine how the cardiovascular strain of hotel and catering industry (HCI) employees who work alternating shifts differs from those working normal day shifts-on both a working day (WD) and a non-working day (ND).

METHODS

The sample consisted of 60 alternating shift (morning and afternoon, mean age: 31.5 ± 8.5 years) and 88 day workers (mean age: 35.3 ± 9.4 years). A 24-h ambulatory measurement of blood pressure (BP) and heart rate (HR) on WD and ND with the time phases DAY, SLEEP, and 24-h TOTAL was used to analyse cardiovascular strain. BP status was assessed by self-measurement (36% hypertensives).

RESULTS

The total strain over 24 h was slightly higher on WD than ND (mean BP: 134/79 versus 127/75 mmHg, P = 0.002-0.020; mean HR: 78 versus 75 bpm, P = 0.055). In trend, shift workers had higher systolic BP than day workers during the individual time phases of DAY, SLEEP, and 24-h TOTAL on WD. Known cardiovascular risk factors emerged as critical determinants of cardiovascular strain: older age, male gender, and hypertensive blood pressure status.

CONCLUSIONS

The results revealed no clear association between the alternating shift system in HCI and increased cardiovascular strain. The 24-h ambulatory measurement is considered ideal for determining cardiovascular strain in everyday life and under working conditions.

Influence of shift work on cardiovascular disease risk in Southern African long-distance truck drivers: a cross-sectional study

OBJECTIVES

Cardiovascular disease (CVD) is a major problem globally. Truck drivers have an increased risk of CVD due to a sedentary lifestyle, irregular working hours and behavioural choices. We aimed to get insight into the contribution of night shift work to CVD risk in long-distance truck drivers in South Africa.

DESIGN

A cross-sectional study.

SETTING

Enrolment took place at three South African truck stop locations in two provinces; Bloemfontein (Free State), Pomona Road (Gauteng) and Soweto (Gauteng).

PARTICIPANTS

607 males aged ≥18 years with full-time employment as a long-distance truck driver were included. The criteria for inclusion were willingness and being able to provide informed consent and to complete the study procedures.

PRIMARY AND SECONDARY OUTCOME MEASURES

Information was collected on sociodemographics, occupational and health characteristics. Physical measurements, an ECG and carotid intima-media thickness (CIMT) measurements were taken. A night shift was defined as working at least 3 hours between 22:00 and 6:00 hours once a week. CVD risk was defined with the Framingham Risk Score (FRS), the Atherosclerotic Cardiovascular Disease (ASCVD) risk algorithm, left ventricular hypertrophy (LVH) and CIMT.

RESULTS

In total, 607 truck drivers were included of which 305 (50.2%) worked in day shifts only and 302 (49.8%) worked day and night shifts. There was a high prevalence of CVD risk factors in both groups as 33% were hypertensive, 28% obese and 37% had abnormal lipid levels. Working day and night shifts compared with working only day shifts did not result in differences in FRS, ASCVD risk or LVH. No difference was found in CIMT measurements, except for the maximum bulb thickness which was higher in day shift workers.

CONCLUSIONS

CVD risk factors are considerably present in male truck drivers in South Africa. CVD risk does not differ between dayshift and day-night shift workers in this cross-sectional analysis.

The Impact of Shift Work on Occupational Health Indicators among Professionally Active Adults: A Comparative Study

The analysis of the impact of shift work on occupational health still needs further contributions. Therefore, we developed this research with the purpose of assessing the impact of shift work on occupational health indicators, namely burnout, work-engagement, occupational self-efficacy, and mental health functioning (symptoms of depression and anxiety), by comparing workers who did shift work (44.2% of participants) with workers who did not (55.8% of participants). A total of 695 Portuguese professionally active adults between 18 and 73 years of age (M_age = 37.71; SD = 12.64) participated in this study and completed a survey containing a sociodemographic questionnaire and four occupational health measures: The Burnout Assessment Tool, The Work-Engagement questionnaire (UWES), The Occupational Self-Efficacy Questionnaire, and the BSI-18 for mental health symptoms. Results showed statistically significant differences (p < 0.05) for all indicators, demonstrating that participants who worked shifts presented lower scores of work-engagement and occupational self-efficacy, and higher scores of burnout, depression, and anxiety when compared to participants who did not work shifts. Linear regressions showed that shift work explained significant but low percentages of anxiety symptoms, low work-engagement, depression symptoms, low occupational self-efficacy, and burnout. We concluded that non-standard working hours (by shifts) are detrimental to employee occupational health, by increasing the risk of anxiety and depression levels, and burnout, and by reducing work-engagement (as a well-being indicator) and occupational self-efficacy perceptions.

Is Shift Work Sleep Disorder a Risk Factor for Metabolic Syndrome and Its Components? A Systematic Review of Cross-Sectional Studies

Shift work sleep disorder is prevalent in night shift workers due to prolonged misalignment of the circadian rhythm. Night shift workers comprise a significant portion of the workforce and it is important to study the potential implications on their health. Studies have shown the association of metabolic syndrome (MetS) and the components, that is, obesity, dyslipidemia, hypertension, and insulin resistance, with shift workers. Nocturnal exposure to bright light can affect various physiological processes including melatonin secretion, which is a regulator in insulin synthesis. A systematic review was conducted to identify studies showing the association between shift work and MetS and/or its components, as well as to review the pathophysiology for further investigations. This review follows the guidelines as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist 2009. One thousand nine hundred ten records were identified from the PubMed database using both keywords and medical subject headings terms. After applying the inclusion/exclusion and eligibility criteria, 18 observational studies were included in the qualitative synthesis. Quality appraisal was conducted by two investigators independently using the Newcastle/Ottawa Scale, and 11 articles were finalized for the review after scoring 60% and above. Each study measured the different components of MetS and/or the presence of MetS. Statistically significant results were reported for the association between shift work and MetS, shift work and obesity, shift work and dyslipidemia, shift work and hypertension, and shift work and insulin resistance. This review identifies a need to emphasize treatment plans for shift workers to manage not only sleep disorders but other chronic diseases such as MetS, obesity, hypertension, dyslipidemia, and insulin resistance.

Cardiovascular and Self-Reported Recovery in Two-Shift Systems

Abstract. Recovery is necessary to maintain workers’ health and efficiency. Shift work has been associated with delayed recovery processes. The objective of this study was to examine the cardiovascular and self-reported recovery measures of German shift and day workers in the hotel and catering industry. Furthermore, it aimed to clarify to what extent shift groups differentiate given additional factors that influence recovery (ability to relax, lifestyle). The sample group consisted of 64 alternative shift workers (two-shift system with a low proportion of night work) and 96-day workers employed in the hotel and catering industry. Blood pressure monitoring was conducted for 24 hr during a working day, including the phases of work, leisure, and sleep, to assess cardiovascular reduction during leisure and sleep. The blood pressure status was measured over the course of a 4-day self-assessment period. Self-reported measures, including quality of sleep (Pittsburgh Sleep Quality Index, PSQI), work-life balance (WPC), ability to relax (FABA), and lifestyle factors (physical activity, smoking, drinking), were assessed through questionnaires. Sixty-one participants (36%) were hypertensives. There were no significant effects of cardiovascular recovery regarding the reduction of blood pressure for the calculated differences between WORK – LEISURE, WORK – SLEEP, and LEISURE – SLEEP among shift and day workers. Shift workers reported a significantly less favorable work-life balance ( p = .017), a decreased ability to relax ( p = .001), and less regular physical activity ( p = .003). The workload within the two-shift system of the hotel and catering industry seems to have a lesser effect on cardiovascular means than on self-reported measures of recovery. The decisive factor is the ability to relax, which means psychological detachment from work. To enable a comprehensive recovery, an optimally designed recovery cycle is necessary for shift systems.

The relationship between rotating shift work and blood pressure among nurses working in hospitals of Abadan, Iran

Hypertension is a major risk factor for developing cardiovascular disease. Various factors such as occupational and environmental risk factors affect blood pressure. Shift work is considered to be an occupational stressor. The aim of this study was to determine the relationship between rotating shift work and blood pressure among nurses working in hospitals associated with faculty of medical science. This cross-sectional and descriptive-analytic study was conducted on nurses who worked in three hospitals associated with faculty of medical science, located in Abadan, southwest of Iran from September until December 2019. The sample size was 120 participants and divided into 60 rotating shift workers and 60 day workers (non-shift workers). The nurses were selected through the stratified random sampling technique. Demographic data, smoking status, and medical and occupational history were collected through a check list and interviews. Blood pressure was measured using a digital sphygmomanometer. Data were analyzed by the Mann-Whitney U, chi-square, Pearson's correlation coefficient and logistic regression by using SPSS software version 22. There was statistically significant difference in blood pressure between day workers and rotating shift workers (p ≤ 0.001). By logistic regression analyses, and even after adjusting for confounding variables, rotating shift work was associated with a higher prevalence of hypertension (OR: 1.76 [95%CI: 1.11-2.80]). The findings of this study showed that rotating shift workers have a higher incidence of hypertension than day workers. Therefore, a particular follow-up of rotating shift workers should be recommended to screen workers for hypertension.

Effect of Sleep Disturbances on Blood Pressure

This review summarizes recent literature addressing the association of short sleep duration, shift work, and obstructive sleep apnea with hypertension risk, blood pressure (BP) levels, and 24-hour ambulatory BP. Observational studies demonstrate that subjectively assessed short sleep increases hypertension risk, though conflicting results are observed in studies of objectively assessed short sleep. Intervention studies demonstrate that mild and severe sleep restriction are associated with higher BP. Rotating and night shift work are associated with hypertension as shift work may exacerbate the detrimental impact of short sleep on BP. Further, studies demonstrate that shift work may increase nighttime BP and reduce BP control in patients with hypertension. Finally, moderate to severe obstructive sleep apnea is associated with hypertension, particularly resistant hypertension. Obstructive sleep apnea is also associated with abnormal 24-hour ambulatory BP profiles, including higher daytime and nighttime BP, nondipping BP, and a higher morning surge. Continuous positive airway pressure treatment may lower BP and improve BP dipping. In conclusion, efforts should be made to educate patients and health care providers about the importance of identifying and treating sleep disturbances for hypertension prevention and management. Empirically supported sleep health interventions represent a critical next step to advance this research area and establish causality.

Time for Novel Strategies to Mitigate Cardiometabolic Risk in Shift Workers

Circadian disruption induced by shift work is robustly associated with obesity, diabetes, and cardiovascular disease in humans. Less well-known are the mechanisms underlying these associations, and the effectiveness of strategies to reduce cardiometabolic risk in the shift work population. In this review, the different ways in which shift work can deteriorate cardiometabolic health, and how to use this information to reflect on various risk-mitigating strategies, is discussed. While individual strategies appear promising in animal studies, the multifactorial disease risk in shift workers likely requires a multidisciplinary approach. Therefore, the need for individually-tailored combined lifestyle interventions, that could be essential in reducing cardiometabolic disorders in the large population of shift workers in our 24/7 society, is argued.

Molecular link between circadian clocks and cardiac function: a network of core clock, slave clock, and effectors

The circadian rhythm has a strong influence on both cardiac physiology and disease in humans. Preclinical studies primarily using tissue-specific transgenic mouse models have contributed to our understanding of the molecular mechanism of the circadian clock in the cardiovascular system. The core clock driven by CLOCK:BMAL1 complex functions as a universal timing machinery that primarily sets the pace in all mammalian cell types. In one specific cell or tissue type, core clock may control a secondary transcriptional oscillator, conceptualized as slave clock, which confers the oscillatory expression of tissue-specific effectors. Here, we discuss a core clock-slave clock-effectors network, which links the molecular clock to cardiac function.

Whole transcriptome analysis of adrenal glands from prenatal glucocorticoid programmed hypertensive rodents

Prenatal glucocorticoid exposure is associated with the development of hypertension in adults. We have previously demonstrated that antenatal dexamethosone (DEX) administration in Wistar-Kyoto dams results in offspring with increased blood pressure coupled with elevated plasma epinephrine levels. In order to elucidate the molecular mechanisms responsible for prenatal DEX-mediated programming of hypertension, a whole-transcriptome analysis was performed on DEX programmed WKY male adrenal glands using the Rat Gene 2.0 microarray. Differential gene expression (DEG) analysis of DEX-exposed offspring compared with saline-treated controls revealed 142 significant DEGs (109 upregulated and 33 downregulated genes). DEG pathway enrichment analysis demonstrated that genes involved in circadian rhythm signaling were most robustly dysregulated. RT-qPCR analysis confirmed the increased expression of circadian genes Bmal1 and Npas2, while Per2, Per3, Cry2 and Bhlhe41 were significantly downregulated. In contrast, gene expression profiling of Spontaneously Hypertensive (SHR) rats, a genetic model of hypertension, demonstrated decreased expression of Bmal1 and Npas2, while Per1, Per2, Per3, Cry1, Cry2, Bhlhe41 and Csnk1D were all upregulated compared to naïve WKY controls. Taken together, this study establishes that glucocorticoid programmed adrenals have impaired circadian signaling and that changes in adrenal circadian rhythm may be an underlying molecular mechanism responsible for the development of hypertension.

BMI differences between different genders working fixed day shifts and rotating shifts: a literature review and meta-analysis

The objective of this study was to perform a systematic literature review and meta-analysis to understand the BMI differences between different genders working fixed day shifts and rotating shifts. The Pubmed, Medline, and Embase databases were searched using set keywords, thereby producing 42 studies. Study quality was assessed using appraisal criteria from the Joanna Briggs Institute (JBI), and meta-analysis was performed using Comprehensive Meta-Analysis Software (CMA) version 3. The indices were the means and standard deviations of BMI values from different genders working fixed day shifts and rotating shifts. The participants of the studies included a total of 43,193 individuals working rotating shifts and 185,875 individuals working fixed day shifts. The pooling effect size (SMD, standardized mean difference) presented was 0.19. The 95% confidence interval ranged from 0.10 to 0.281. The meta-regression analysis results showed that women had higher BMI values than men, the difference was statistically significant (p <.001). The heterogeneity test indicated statistically significant differences (p <.05), and the percentage of heterogeneity (I square) was 97.91%, which indicates that a high degree of heterogeneity exists among studies. A subgroup analysis by gender was conducted. For women, the pooling effect size was 0.25, and the 95% confidence interval ranged from 0.20 to 0.30. For men, the pooling effect size was 0.19, and the 95% confidence interval ranged from 0.05 to 0.33. This meta-analysis found that both women and men working rotating shifts have significantly higher BMI values than those working fixed day shifts. Finally, we divided the data into a cross-sectional group and a cohort group based on study design, and a meta-regression analysis conducted after controlling for age and nature of work variables revealed that in the cohort study, women presented higher BMI values than men, and the difference was statistically significant (p =.010). Thus, in terms of long-term effects, these results indicate that working rotating shifts exerts a greater impact on the BMI of women.

Molecular Mechanisms Underlying the Circadian Rhythm of Blood Pressure in Normotensive Subjects

PURPOSE OF REVIEW

Blood pressure (BP) follows a circadian rhythm (CR) in normotensive subjects. BP increases in the morning and decreases at night. This review aims at providing an up-to-date overview regarding the molecular mechanisms underlying the circadian regulation of BP.

RECENT FINDINGS

The suprachiasmatic nucleus (SCN) is the regulatory center for CRs. In SCN astrocytes, the phosphorylated glycogen synthase kinase-3β (pGSK-3β) also follows a CR and its expression reaches a maximum in the morning and decreases at night. pGSK-3β induces the β-catenin migration to the nucleus. During the daytime, the nuclear β-catenin increases the expression of the glutamate excitatory amino acid transporter 2 (EAAT2) and glutamine synthetase (GS). In SCN, EAAT2 removes glutamate from the synaptic cleft of glutamatergic neurons and transfers it to the astrocyte cytoplasm where GS converts glutamate into glutamine. Thus, glutamate decreases in the synaptic cleft. This decreases the stimulation of the glutamate receptors AMPA-R and NMDA-R located on glutamatergic post-synaptic neurons. Consequently, activation of NTS is decreased and BP increases. The opposite occurs at night. Despite several studies resulting from animal studies, the circadian regulation of BP appears largely controlled in normotensive subjects by the canonical WNT/β-catenin pathway involving the SCN, astrocytes, and glutamatergic neurons.

Association of dyslipidemia, hypertension and overweight/obesity with work shift and duration of employment among police officers in a small town in Northeastern Brazil

BACKGROUND

Metabolic syndrome and chronic diseases have impact on the job performance of police officers.

OBJECTIVE

To investigate the association of overweight/obesity and cardiovascular risk factors with work shift and duration of employment among police officers.

METHODS

Cross-sectional study with 102 police officers in Cajazeiras, Paraíba, Brazil, in which we analyzed sociodemographic data, occupational characteristics, body mass index (BMI), lipid profile, personal history of disease and lifestyle. Statistical analysis included the chi-square and Fisher's exact test.

RESULTS

Overweight/obesity was found among most participants (83.3%). Hypertriglyceridemia (49.1%), low HDL-C (56.9%) and high LDL-C (46.1%) levels were associated with abnormal BMI (p<0.05). Hypertension was the main disease reported by overweight/obese participants (28.2%) (p=0.01). Job position, lifestyle and work shift were not associated with any of the analyzed variables, however, abnormal BMI, dyslipidemia, and hypertension were frequent among the participants with 6-10 or more than 10 years in the job (p<0.05).

CONCLUSION

Part of the participants with at least 6 years in the job exhibited overweight/obesity in association with dyslipidemia and hypertension. We recommend prevention and therapeutic strategies to protect officers from chronic diseases or attenuate their long-term complications. Additional prospective studies are needed to confirm the associations we found, mainly between duration of employment and occupational diseases.

Upper limb vascular mapping with Doppler ultrasound: Technique precision evaluated in healthy volunteers

Introduction

Doppler ultrasound is recommended by international societies for preoperative vascular mapping in vascular access surgery. Literature is scarce regarding data on Doppler ultrasound-associated errors.

Objectives

Our aim was to evaluate Doppler ultrasound precision for upper limb vascular mapping.

Methods

Fifty-two adult healthy volunteers were evaluated for superficial vein diameter, brachial artery flow and diameter in the lower third of non-dominant arm by a dedicated vascular access radiologist blinded for the identification of the participants. Each participant was scheduled for three evaluations one week apart. Friedman test and multivariate analysis of variance for repeated measures were used.

Results

There were no statistical differences within subjects across the three weeks except for brachial artery flow in participants who had basilic vein as the dominant vein.

Discussion

Repeated anatomical and haemodynamic parameters measured by Doppler ultrasound performed by an experienced medical sonographer, according to our protocol, did not show statistical differences within subjects, independently of age, gender and body mass index.

The Effect of Special Medical Examination for Night Shift Workers and Follow-Up Management Against Hypertension

Background: Special health examination is a screening program introduced in 1973 in Korea to examine health problems of workers who are regularly exposed to 177 hazardous substances and physical environments specified by the Occupational Safety and Health Act. Shiftwork was added as a risk factor in 2013. The purpose of this study was to analyze changes of hypertension status after a special medical examination and subsequent follow-up management. Methods: We used the data based on the special medical examination outcomes for night shift workers, performed at seven different health examination centers under the Korea Medical Institute (KMI) between 2014 and 2016. Workers who received special medical examinations for two consecutive years (2014–2015 and 2015–2016) were selected. A final study population of 2070 was evaluated. Results: Compared with the first-year examination, 1503 subjects (72.6%) received hypertension medication or showed improvement in blood pressure in their second-year examination. Older age (≥40s), women, larger workplaces (≥300 full-time workers), long-term workers (≥12 years), improvement in smoking habits, improvements for diabetes or dyslipidemia, normal or reduced BMI, and normal waist circumference were associated with proper management of hypertension. Conclusions: An appropriate follow-up management program should be developed to provide health management for night shift workers that need to focus on the factors identified in this study.

Working in Shifts and the Metabolic Syndrome: Epidemiological Evidence and Physiopathological Mechanisms

The Metabolic syndrome (MetS) is considered as an association of the abdominal obesity, abnormal metabolism of the lipids and glucose (high level of triglycerides, low level of HDL-cholesterol and high level of glycemia) and high values of blood pressure, determined by an underlying mechanism of insulin resistance. As a result of environmental-gene interaction, MetS is associated with unhealthy nutrition, smoking, alcohol abuse, lack of physical activity, shorter sleep duration and desynchronization of the circadian rhytm caused by working in shifts. The aim of this article is to review the effects of working in shifts on the MetS through the epidemiological evidence and the perspective of the physiopathological mechanisms.

Night and rotational work exposure within the last 12 months and risk of incident hypertension

Objectives Shift work, such as alternating day and nights, causes chronobiologic disruptions which may cause an increase in hypertension risk. However, the relative contributions of the components of shift work ‒ such as shift type (eg, night work) and rotations (ie, switching of shift times; day to night) ‒ on this association are not clear. To address this question, we constructed novel definitions of night work and rotational work and assessed their associations with risk of incident hypertension. Methods A cohort of 2151 workers at eight aluminum manufacturing facilities previously studied for cardiovascular disease was followed from 2003 through 2013 for incident hypertension, as defined by ICD-9 insurance claims codes. Detailed time-registry data was used to classify each worker's history of rotational and night work. The associations between recent rotational work and night work in the last 12 months and incident hypertension were estimated using adjusted Cox proportional hazards models. Results Elevated hazard ratios (HR) were observed for all levels of recent night work (>0-5, >5-50, >50-95, >95-100%) compared with non-night workers, and among all levels of rotational work (<1, 1-10, >10-20, >20-30, and >30%) compared with those working <1% rotational work. In models for considering the combination of night and rotational work, workers with mostly night work and frequent rotations (≥50% night and ≥10% rotation) had the highest risk of hypertension compared to non-night workers [HR 4.00, 95% confidence interval (CI )1.69-9.52]. Conclusions Our results suggest recent night and rotational work may both be associated with higher rates of incident hypertension.

Cardiovascular recovery after workload in German shift workers in the hotel and catering industry: results of 24-hour-ambulatory monitoring of heart rate and blood pressure

PURPOSE

Shift work is associated with an impairment of sleep-wake cycles that can affect cardiovascular recovery (CR) negatively. The aim of this study was to examine CR of shift and day workers in the hotel and catering industry (HCI) and identify predictors of CR.

METHODS

The sample consisted of 64 alternating and 96 day workers in the HCI. Monitoring of blood pressure (BP) and heart rate (HR) was conducted for 24 hours per working day during work, leisure and sleep. The CR process was examined for differences between work and leisure, work and sleep regarding a reduction in BP and HR. Lifestyle (physical activity, smoking, drinking) was assessed through questionnaires, BP over a four-day, self-assessment period (38% hypertensives). Participants taking BP medication (n = 12) were excluded from analyses.

RESULTS

Shift workers had significantly higher BP (Ø 146/87 vs. Ø 140/84 mmHg; p = 0.034-0.044) and HR (Ø 86 vs. 82 bpm; p = 0.032) during their work phase verses day workers. There were no differences found for the CR between work and leisure nor work and sleep. As predictors of the CR, classic cardiovascular indicators (blood pressure status, smoking, age, physical activity, sex) were found which explains between 14% (HR) and 30% (BP) of the variance. Shift work was not a predictor for CR.

CONCLUSIONS

Employees in the HCI show that their CR is mainly determined by the known cardiovascular indicators and less by shift work. This effect needs to be discussed in relation to the job requirements and the cardiovascular health of the employees.

Association between serum ferritin and hypertension according to the working type in Korean men: the fifth Korean National Health and nutrition examination survey 2010-2012

Background

Several studies suggest that serum ferritin concentrations reflect systemic inflammation, and high ferritin levels can increase the risk of hypertension in adult men. Shift work is also known to increase the risk of hypertension; however, there has been no study about the relationship between serum ferritin levels and the prevalence of hypertension according to the working type.

Methods

This cross-sectional study included 4,442 male participants (3,651 daytime workers and 791 shift workers) who participated in the fifth Korean National Health and Nutrition Examination Survey. Hypertension was defined as a systolic blood pressure greater than or equal to 140 mmHg, a diastolic blood pressure greater than or equal to 90 mmHg or the current use of antihypertensive medications regardless of blood pressure values. For the statistical analyses, serum ferritin levels were reclassified into quartiles, and complex sample analyses were used to evaluate the relationship between serum ferritin levels and the prevalence of hypertension according to the working type in this study.

Results

Serum ferritin and shift work were positively associated with the prevalence of hypertension. The effect of interaction was above multiplicative. When compared to participants in the lowest serum ferritin quartile, the odds ratio for hypertension for participants in the highest serum ferritin quartile was 1.372 (1.027–1.833) in daytime workers and 2.009 (1.042–3.873) in shift workers after adjustment.

Conclusions

The prevalence of hypertension increased as ferritin levels increased in individuals, especially in shift workers.

Breast cancer screening among shift workers: a nationwide population-based survey in Korea

We aimed to examine the association between shift work types and participation in breast cancer screening (BCS) programs by comparing rates of participation for BCS among regular daytime workers and alternative shift workers using data from a nationally representative, population-based survey conducted in Korea. In addition, the results were analyzed according to sociodemographic factors, including occupation, education, income, private health insurance, age, and number of working hours a week. This secondary cross-sectional analysis used data from the 2012 Korean National Health and Nutritional Examination Survey. The target population included women aged ≥ 40 years who responded as to whether they had undergone BCS in the previous year. Accordingly, we analyzed survey data for a total of 1,193 women and used a multivariate logistic regression analysis to evaluate the differences in factors affecting BCS between regular daytime and alternative shift workers. A logistic regression analysis was performed considering private health insurance as a significant sociodemographic factor for BCS among regular daytime shift workers. In contrast, none of the tested variables could significantly predict adherence to BCS among alternative shift workers. The results of this study suggest the need for the development of comprehensive workplace breast cancer prevention programs by considering shift work types. More attention should be given to female workers with low education levels, those who are uninsured, and young workers to improve the participation rate for BCS at the workplace.

Prevalence of Hypertension in Professional Drivers (from the RACER-ABPM Study)

Professional drivers are a group exposed to many cardiovascular risk factors. Nonsystematic working hours, stress, low physical activity, and unhealthy dietary habits are common among professional drivers. These translate into high risk of cardiovascular disease. The aim of the current analysis was to establish the prevalence of arterial hypertension in a group of continuous professional drivers. The RACER (Risk of Adverse Cardiovascular Events among professional dRivers in Poland) study is a prospective study focused on assessing cardiovascular risk factors in professional drivers. Patients included in the study were screened for the classical and nonclassical cardiovascular risk factors and had an ambulatory blood pressure monitoring (ABPM) performed. Of the RACER study population, 144 drivers were included into the RACER-ABPM study. Of this group 135 (95.7%) were male at mean age of 50.2 ± 9.3 years, with mean body mass index of 32.3 ± 3.0 kg/m². In 21.3% of patients, family history of cardiovascular disease was noted, 28.1% were current smokers, and 2.9% had diabetes mellitus. Arterial hypertension was previously diagnosed in 39 patients (27.9%). In ABPM, the mean 24-hour blood pressure (BP) values were 130.3 ± 14.3 and 80.9 ± 9.9 for systolic and diastolic BP, respectively, and 46.1% of patients could be categorized as dippers. Based on the ABPM results, arterial hypertension was diagnosed in 104 of patients (73.8%). Patients with hypertension tend to be more often male and have a family history of cardiovascular disease. In conclusion, arterial hypertension is highly prevalent in professional drivers. Also abnormal day-to-night BP value patterns are often seen in this group.