Health Effects Of Shift Work Research Articles

Shift Work and Associated Health Consequences: A Review

This literature review aims to examine the complex relationship between engaging in shift work and its subsequent health sequelae, while also shedding light on fields of research that require further investigation. Indexing services (i.e., Scopus and PubMed) were used to identify pertinent studies, prioritizing original research, review articles, and meta-analyses from 2018 to 2023. Papers not published in English or where full-text translation was not available, research conducted solely on non-human populations, as well as proposal and opinion papers, were excluded. Papers published before 2018 and those with a sample size of 50 participants or fewer were also omitted. The author conducted a thorough evaluation of each study to ensure its relevance and significance. After deduplication of the search results and implementation of the exclusion criteria, 51 papers were shortlisted for this review. The keywords used for the literature search were “shift work”, “health”, “night shift”, “cardiovascular”, “circadian, cancer”, “disease”, “dose-response relationship”, and “long working hours”. The results showed that shift work significantly impacts various aspects of health, presenting risks in the areas of cardiovascular health, cancer susceptibility, circadian rhythm, immunity, metabolism, reproductive health, and mental well-being. Shift workers have increased risks for diabetes, hypertension, adverse cardiac events, circadian dysrhythmia, metabolic syndrome, mental health disorders, and even certain types of cancer. Shift work exhibits significant associations with sexual and reproductive dysfunction in both sexes, including elevated risks for miscarriages and preterm birth. In conclusion, the findings underscore the need for comprehensive health interventions and further research to understand the intricate relationships between shift work and long-term health consequences. Highlights: Disruption of circadian rhythm due to shift work contributes to various health issues, including altered melatonin levels, immune dysfunction, and metabolic disturbances. There is a critical need for longitudinal studies to explore interventions and workplace policies that can mitigate the adverse health effects of shift work. Addressing the multifaceted impact of shift work on health requires a holistic approach that considers factors like circadian rhythm optimization, workplace support, and tailored interventions.

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

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

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

ABSTRACT 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.

Effects of working conditions on the perception of night work safety and health effects on nurses.

To examine night working conditions by shift work type and identify the effects of night working conditions on nurses' perceptions of shift work safety and health effects. Night work is the main factor affecting nurses' health. However, the safety of night working conditions has not been sufficiently examined in previous studies. This study used a cross-sectional research design and an online survey using a tool released by the Australian Manufacturing Workers' Union, and the responses of 348 shift work nurses in Korea were analyzed. Logistic regression analysis was used to examine the effects of shift work conditions on the perceived safety of night work and health effects. The STROBE reporting guidelines were utilized, and data were collected from December 1 to December 31, 2021. The adjusted logistic regression analysis showed that perceived threat to safety and the health effects of shift work were not significant according to shift type. However, night-shift-work nurses who worked alone (P=0.003), lacked an emergency recovery system (P=0.026), and had difficulty commuting perceived a threat to their health (P=0.007). Additionally, nurses who experienced loss of concentration (P=0.006) and inadequate rest time (P<0.001) perceived the health effects of shift work. Urgent monitoring of night work conditions is necessary for the 2-shift work type. Nurses must work night shifts together and an emergency system should be established for their safety. Night work conditions should be improved to prevent the hazards of night work and its negative health effects on nurses. This study suggests the necessity of a policy to enhance night work safety, including emergency coping systems and sufficient inter-shift rest time.

Study of the physiological effects of shift work using the HRV analysis method

Shift work in industry and services cannot be avoided, but the adverse health effects of shift work are well known. The results of workplace physiological measurements in the Hungarian solid mineral mining oil and gas extraction and processing industry was, carried out under the coordination of the Scientific Committee on Mining Health and Ergonomics of the Hungarian Academy of Sciences, The Committee studiedy the variations of age and life characteristics of the workers, the various working conditions and environment and the heart rate variability (HRV) parameters. Our workplace studies covered 8, 12 and 24-hour shift works alike during morning, afternoon and night shifts with 2, 5 or 7 days per shift. In the evaluation, the significant differences in HRV parameters reflecting different physiological conditions, working conditions and work environment are presented for the morning only (control group) and the shift work groups. Evaluation of the results of the measurements carried out at the workplaces adjusted to the actual work schedule using known methods of mathematical statistics made it possible to investigate the effects of different circumstances and conditions. Based on the reviewed research results regarding the health effects of shift work, IARC/WHO concluded in 2010 that shift work was probably carcinogenic to humans (category 2A) - a recommendation that was changed to night shift work in 2019, based on the research results revealed in the meantime. Our studies call attention to the potential for using the results of new methods developed through innovation and to the justification for their use in occupational health.

The Effects of Shift Work on Cardio-Metabolic Diseases and Eating Patterns.

Energy metabolism is tightly linked with circadian rhythms, exposure to ambient light, sleep/wake, fasting/eating, and rest/activity cycles. External factors, such as shift work, lead to a disruption of these rhythms, often called circadian misalignment. Circadian misalignment has an impact on some physiological markers. However, these proxy measurements do not immediately translate into major clinical health outcomes, as shown by later detrimental health effects of shift work and cardio-metabolic disorders. This review focuses on the effects of shift work on circadian rhythms and its implications in cardio-metabolic disorders and eating patterns. Shift work appears to be a risk factor of overweight, obesity, type 2 diabetes, elevated blood pressure, and the metabolic syndrome. However, past studies showed discordant findings regarding the changes of lipid profile and eating patterns. Most studies were either small and short lab studies, or bigger and longer cohort studies, which could not measure health outcomes in a detailed manner. These two designs explain the heterogeneity of shift schedules, occupations, sample size, and methods across studies. Given the burden of non-communicable diseases and the growing concerns about shift workers’ health, novel approaches to study shift work in real contexts are needed and would allow a better understanding of the interlocked risk factors and potential mechanisms involved in the onset of metabolic disorders.

A Longitudinal Study of the Relationship between Shift Work and Prostate-Specific Antigen in Healthy Male Workers.

As shift work has become prevalent globally, it is important to evaluate the health effects of shift work on employees. Several studies have demonstrated a positive association between shift work and prostate cancer. Therefore, we aimed to further examine the relationship between shift work and elevated prostate-specific antigen (PSA). Our study collected data from 66,817 male participants at baseline and followed up for about 6 years. We categorized shift worker status and shift schedule types. To evaluate the risk of elevated PSA on shift workers, we estimated hazard ratios using the Cox proportional hazards regression analyses. During a median follow-up of 4.1 years, 1030 participants developed elevated PSA. The multivariable-adjusted hazard ratio (HR) of elevated PSA for shift workers compared with daytime workers was 1.37 (1.04–1.80). Among shift workers, rotating shift workers (HR = 1.47, 95% CI 1.06–2.03) showed a significantly increased risk of elevated PSA compared with daytime workers. Our longitudinal study provides evidence for an association between shift work, especially rotating shift work, and elevations of PSA.

Shift work and incidence of psychiatric disorders: The Danish Nurse Cohort study

BackgroundResearch on health effects of shift work has especially focused on somatic diseases, such as breast cancer and cardiometabolic disease, while less attention has been given to the association between shift work and mental health. MethodsWe used information on 19 964 female nurses (≥44 years) from the Danish Nurse Cohort, who reported current work schedule (day, evening, night, or rotating) at recruitment (1993/1999). In 5102 nurses who participated in both cohort waves, we defined persistent night shift work as working night shift in 1993 and 1999. We used Cox regression models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for relevant confounders.Through linkage of cohort participants to national registers, we defined incidence of mood and neurotic disorders as first hospital contact or redeemed prescription until November 2018. ResultsWe found association between night shift work with mood disorders (HR = 1.31; 95%CI = 1.17–1.47) and neurotic disorders (1.29; 1.17–1.42), compared to day work. Associations were enhanced in nurses with persistent night shift work (1.85; 1.43–2.39 and 1.62; 1.26–2.09 for mood and neurotic disorders, respectively) and in nurses with specialist confirmed mood (1.69; 1.24–2.29) and neurotic (1.72; 1.22–2.44) disorders. Nurses with preexisting psychiatric disorders and full-time work seemed most susceptible. ConclusionsNight shift work is associated with increased risk of major psychiatric disorders. The novel suggestive findings of vulnerable groups, including nurses with a history of psychiatric disorders and full-time workers, are based on a limited number of cases, and further research is needed to confirm the results.

The mediating role of lifestyle in the relationship between shift work, obesity and diabetes

PurposeShift work has been related to obesity and diabetes, but the potential mediating role of lifestyle is yet unknown. Our aim was to investigate this mediating role of physical activity, diet, smoking, and sleep quality in the relationships between shift work, and obesity and diabetes.MethodsIn this cross-sectional study, 3188 shift workers and 6395 non-shift workers participated between 2013 and 2018 in periodical occupational health checks. Weight and height were objectively measured to calculate obesity (BMI ≥ 30 kg/m2). Diabetes status, physical activity, diet, smoking, and sleep quality were assessed using standardized questionnaires. Structural equation models adjusted for relevant confounders were used to analyze the mediating role of lifestyle in the relationships between shift work, and obesity and diabetes.ResultsShift workers were more often obese (OR: 1.37, 95% CI 1.16–1.61) and reported more often to have diabetes (OR:1.35, 95% CI 1.003–1.11) than non-shift workers. Shift workers had lower physical activity levels, ate fruit and vegetables less often, smoked more often, and had poorer sleep quality (p < 0.05). Mediation analysis revealed that shift workers had a higher odds of obesity (OR: 1.07, 95% CI 1.01–1.15) and diabetes (OR: 1.13, 95% CI 1.02–1.27) mediated by poorer sleep quality. Lower physical activity levels (OR: 1.11, 95% CI 1.05–1.19) and lower intake of fruit and vegetables (OR: 1.04, 95% CI 1.01–1.15) were also mediators in the relationship between shift work and obesity, but not in the relationship between shift work and diabetes (p ≥ 0.05).ConclusionThese results imply that interventions targeting diet, physical activity and in particular sleep problems specifically developed for shift workers could potentially reduce the adverse health effects of shift work.

The association of Shift Work and Effort–Reward Imbalance with Gastrointestinal Symptoms among Female Nurses

Background: Shift work impacts workers' health, mainly by disrupting the circadian rhythm, and gastrointestinal (GI) disturbances are among the health effects of shift work. Objectives: The objective of this study was to assess the association between shift work, work stress, and GI disturbance among nurses. Methods: In July 2018, a cross-sectional study was conducted in Dammam Medical Complex, Saudi Arabia. A total of 250 nurses were selected through convenience sampling from several departments. They completed a validated questionnaire, which included questions about their demographic data, GI symptoms, and effort–reward imbalance (ERI). Work stress was classified into two groups based on the ERI ratio. GI symptoms were categorized into three indices: total, upper, and lower GI. The sampling plan was designed to cover most of the shifts in the included departments throughout nonspecified dates. The daytime nurses' group was selected from the same hospital as a comparison group to the shift workers. Means and standard deviations were calculated for continuous variables and frequencies and percentages were calculated for categorical variables. The associations were assessed using the Chi-squares and analysis of variance. Results: Work stress among nurses, as measured by the ERI scale, was strongly associated with both upper and lower GI symptoms, with odds ratios of 5.7 (CI: 3.3–7.9) and 2.2 (CI: 1.8–4.3), respectively. The total GI symptom score of the shift workers was greater than that for the daytime workers, with means of 7.8 ± 6.9 and 5.4 ± 5.1, respectively (P = 0.005). Multivariable regression analysis showed that ERI was associated with both lower and upper GI symptoms after adjusting for shift work and years on the job. Conclusions: Shift work was associated with the high prevalence of GI symptoms. Stress (ERI) increased the risk for GI disturbance. Controlling work stress is necessary because it affects nurses' physical and social health, as well as their performances at work and the quality of care they provide.

Cardiovascular Health Effects of Shift Work with Long Working Hours and Night Shifts: Study Protocol for a Three-Year Prospective Follow-Up Study on Industrial Workers.

There is a plausible association between shift work and cardiovascular disease (CVD), which may be due to disruption of the circadian rhythm causing hormonal changes and metabolic disturbances, resulting in high blood pressure, atherosclerosis, diabetes, and being overweight. However, few studies have investigated the association between several consecutive long work shifts, including night shifts, and risk factors for developing CVD. Moreover, knowledge is lacking on factors that may modify or enhance this suggested relationship. The study period is planned from the third quarter of 2018 to the fourth quarter of 2021, and will involve 125 industrial employees at two Norwegian enterprises producing insulation. The work schedule is either rotating shiftwork (morning, evening, night) or regular day work. At baseline, we will measure blood parameters, including markers of inflammation, lipids, and glycosylated hemoglobin. We will also collect measures of blood pressure, resting heart rate, arterial stiffness, carotid intima-media thickness, and aerobic fitness. At the end of baseline data collection, a subgroup will undergo a supervised high-intensity interval training intervention for eight weeks, initiated by the Occupational Health Service. At one-year follow-up, we repeat baseline measures with added measures of heart rate variability and additional five weeks monitoring of sleep and physical activity, and assessment of respirable dust. At the two year follow-up, we will measure CVD risk factors before and after a planned three-month shutdown in one of the studied plants. We will also assess respirable dust, monitor sleep, and compile a one-year retrospective detailed overview of working hours. A final data collection, similar to the one at baseline, will be carried out after three years. We will use a comprehensive set of methods to identify the effects of shift work with long working hours and night shifts on cardiovascular health. This will provide new knowledge on the association between early manifestations of CVD and occupational exposure to shift work. Further, we can study whether work organization such as extensive overtime, sleep loss, and dust exposure have detrimental effects, and if a three-month cease in shift work or increased physical activity will modify early manifestations of CVD.

Time-restricted feeding improves adaptation to chronically alternating light-dark cycles

Disturbance of the circadian clock has been associated with increased risk of cardio-metabolic disorders. Previous studies showed that optimal timing of food intake can improve metabolic health. We hypothesized that time-restricted feeding could be a strategy to minimize long term adverse metabolic health effects of shift work and jetlag. In this study, we exposed female FVB mice to weekly alternating light-dark cycles (i.e. 12 h shifts) combined with ad libitum feeding, dark phase feeding or feeding at a fixed clock time, in the original dark phase. In contrast to our expectations, long-term disturbance of the circadian clock had only modest effects on metabolic parameters. Mice fed at a fixed time showed a delayed adaptation compared to ad libitum fed animals, in terms of the similarity in 24 h rhythm of core body temperature, in weeks when food was only available in the light phase. This was accompanied by increased plasma triglyceride levels and decreased energy expenditure, indicating a less favorable metabolic state. On the other hand, dark phase feeding accelerated adaptation of core body temperature and activity rhythms, however, did not improve the metabolic state of animals compared to ad libitum feeding. Taken together, restricting food intake to the active dark phase enhanced adaptation to shifts in the light-dark schedule, without significantly affecting metabolic parameters.

The effect of sleep deprivation and disruption on DNA damage and health of doctors.

Observational studies have highlighted the detrimental health effects of shift work. The mechanisms through which acute sleep deprivation may lead to chronic disease have not been elucidated, but it is thought that increased DNA damage or decreased repair can lead to disease. The objective of this study was to examine the effects of acute sleep deprivation on DNA damage. This was a cross-sectional observational study on 49 healthy, full-time doctors. Baseline blood was sampled from each participant after three consecutive days of adequate sleep. Participants (n=24) who were required to work overnight on-site had additional blood sampled on a morning after acute sleep deprivation. DNA damage and expression of DNA repair genes were quantified. Information on health, working patterns and sleep diaries were collected. Independent t-tests were used to compare differences between groups and standardised mean differences expressed as Cohen's d. Overnight on-site call participants had lower baseline DNA repair gene expression and more DNA breaks than participants who did not work overnight (d=1.47, p=0.0001; and 1.48, p=0.0001, respectively). In overnight on-site call participants, after acute sleep deprivation, DNA repair gene expression was decreased (d=0.90, p=0.0001) and DNA breaks were increased (d=0.87, p=0.0018). Sleep deprivation in shift workers is associated with adverse health consequences. Increased DNA damage has been linked to the development of chronic disease. This study demonstrates that disrupted sleep is associated with DNA damage. Furthermore, larger prospective studies looking at relationships between DNA damage and chronic disease development are warranted, and methods to relieve, or repair, DNA damage linked to sleep deprivation should be investigated.

Objectively measured physical activity of hospital shift workers.

Objectives Shift work may alter workers' leisure-time and occupational physical activity (PA) levels, which might be one of the potential underlying mechanisms of the negative health effects of shift work. Therefore, we compared objectively measured PA levels between hospital shift and non-shift workers. Methods Data were used from Klokwerk+, a cohort study examining the health effects of shift work among healthcare workers employed in hospitals. In total, 401 shift workers and 78 non-shift workers were included, all of whom wore Actigraph GT3X accelerometers for up to seven days. Time spent sedentary, standing, walking, running, stairclimbing, and cycling during leisure time and at work was estimated using Acti4 software. Linear regression was used to compare proportions of time spent in these activities between hospital shift and non-shift workers. Results Average accelerometer wear-time was 105.9 [standard deviation (SD) 14.0] waking hours over an average of 6.9 (SD 0.6) days. No differences between hospital shift and non-shift workers were found in leisure-time PA (P>0.05). At work, shift workers were less sedentary [B=-10.6% (95% CI -14.3- -6.8)] and spent larger proportions of time standing [B=9.5% (95% CI 6.4-12.6)] and walking [B=1.2% (95% CI 0.1-2.2)] than non-shift workers. However, these differences in occupational PA became smaller when the number of night shifts during accelerometer wear-time increased. Conclusions Leisure-time PA levels of hospital shift workers were similar to those of non-shift workers, but shift workers were less sedentary and more physically active (ie, standing/walking) at work. Future research to the role of occupational activities in the health effects of shift work is recommended.

Nightshift work, chronotype, and genome-wide DNA methylation in blood

ABSTRACTMolecular mechanisms underlying the negative health effects of shift work are poorly understood, which remains a barrier to developing intervention strategies to protect the long-term health of shift workers. We evaluated genome-wide differences in DNA methylation (measured in blood) between 111 actively employed female nightshift and 86 actively employed female dayshift workers from the Seattle metropolitan area. We also explored the effect of chronotype (i.e., measure of preference for activity earlier or later in the day) on DNA methylation among 110 of the female nightshift workers and an additional group of 131 male nightshift workers. Methylation data were generated using the Illumina Infinium HumanMethylation450 BeadChip (450K) Array. After applying the latest methylation data processing methods, we compared methylation levels at 361,210 CpG loci between the groups using linear regression models adjusted for potential confounders and applied the false-discovery rate (FDR) ≤ 0.05 to account for multiple comparisons. No statistically significant associations at the genome-wide level were observed with shift work or chronotype, though based on raw P values and absolute effect sizes, there were suggestive associations in genes that have been previously linked with cancer (e.g., BACH2, JRK, RPS6KA2) and type-2 diabetes (e.g., KCNQ1). Given that our study was underpowered to detect moderate effects, examining these suggestive results in well-powered independent studies or in pooled data sets may improve our understanding of the pathways underlying the negative health effects of shift work and the influence of personal factors such as chronotype. Such an approach may help identify potential interventions that can be used to protect the long-term health of shift workers.

The Association Between Shift Work and Health Behavior: Findings from the Korean National Health and Nutrition Examination Survey

BackgroundShift workers are increasing worldwide, and various negative health effects of shift work have been reported. This study aimed to evaluate the relationship between shift work and health behavior.MethodsThis cross-sectional study included a total of 11,680 Korean adults (6,061 men and 5,619 women) aged ≥20 years old who participated in the Fifth Korean National Health and Nutrition Examination Survey, 2010–2012. Multiple logistic regression analysis was performed to evaluate the association between shift work and health behavior after adjusting for covariates.ResultsIn men, shift work was associated with an increased risk of inadequate sleep (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.00 to 1.40) compared to day work. In women, shift work was associated with an increased risk of smoking (OR, 1.73; 95% CI, 1.34 to 2.22) and inadequate sleep (OR, 1.24; 95% CI, 1.05 to 1.47) compared to day work. In an age-stratified subgroup analysis, female shift workers aged ≥50 years old demonstrated an increased risk of smoking (OR, 5.55; 95% CI, 3.60 to 8.55), alcohol consumption (OR, 2.22; 95% CI, 1.53 to 3.23), and inadequate sleep (OR, 1.50; 95% CI, 1.10 to 2.05) compared to female day workers.ConclusionShift work is associated with worse health behavior, and this is most evident in women aged ≥50 years. Targeted strategies to reduce the negative health effects of shift work should be implemented, with consideration of shift workers' demographic characteristics.

Non-occupational physical activity levels of shift workers compared with non-shift workers

ObjectivesLack of physical activity (PA) has been hypothesised as an underlying mechanism in the adverse health effects of shift work. Therefore, our aim was to compare non-occupational PA levels between...

The Relationship Between Shift Work and Metabolic Risk Factors: A Systematic Review of Longitudinal Studies.

Although the metabolic health effects of shift work have been extensively studied, a systematic synthesis of the available research is lacking. This review aimed to systematically summarize the available evidence of longitudinal studies linking shift work with metabolic risk factors. A systematic literature search was performed in 2015. Studies were included if (1) they had a longitudinal design; (2) shift work was studied as the exposure; and (3) the outcome involved a metabolic risk factor, including anthropometric, blood glucose, blood lipid, or blood pressure measures. Eligible studies were assessed for their methodologic quality in 2015. A best-evidence synthesis was used to draw conclusions per outcome. Thirty-nine articles describing 22 studies were included. Strong evidence was found for a relation between shift work and increased body weight/BMI, risk for overweight, and impaired glucose tolerance. For the remaining outcomes, there was insufficient evidence. Shift work seems to be associated with body weight gain, risk for overweight, and impaired glucose tolerance. Overall, lack of high-methodologic quality studies and inconsistency in findings led to insufficient evidence in assessing the relation between shift work and other metabolic risk factors. To strengthen the evidence, more high-quality longitudinal studies that provide more information on the shift work schedule (e.g., frequency of night shifts, duration in years) are needed. Further, research to the (mediating) role of lifestyle behaviors in the health effects of shift work is recommended, as this may offer potential for preventive strategies.

The Adverse Health Effects of Shift Work in Relation to Risk of Illness/Disease: A Review

Summary Biological rhythm of sleeping is a natural disparity in an organism corresponding to and in reply to cyclic environmental changes, such as daylight hours and hours of darkness or elevated and low down flow. There is some evidence, based upon epidemiological studies as well as studies upon smaller groups of subjects, that individuals who work during the night and sleep during the daytime show cognitive impairment at work, have poorer and fragmented daytime sleep, and have increased risks of developing a wide range of social, psychological, physiological and medical impairments and disorders. Circadian rhythms are one of the most important effective factors on the physiological and physical performances of humans and disturbing this normal rhythm leads to different groups of diseases. The majority of investigations in biological rhythm demeanor vary noticeably in regards to the exact type of disease, population and protocols of sampling over the other outcomes or issues. We conducted a systematic review of [Science Direct, Pubmed, Scopus] to identify influence of different kinds of diseases among shift workers in response to abnormal rhythm of sleeping. The results of this review indicate that abnormal patterns of sleeping can lead to immunological issues, hypertension, metabolic syndrome, insomnia, cardiovascular disease, obesity and depression. It is vital for subsequent investigations to find a way to reduce negative effects (such as decreased amount of works’ time and altered diet) without side effects to help them.

Shift schedules, work factors, and mental health among onshore and offshore workers in the Norwegian petroleum industry.

The purpose of the present study was to answer the following research questions: (1) Do workers in different shift schedules differ in mental distress? (2) Do workers in different shift schedules differ in neuroticism? (3) Do shift schedules differ in psychosocial work exposures? (4) Do psychosocial work exposures contribute to mental distress among onshore- and offshore workers? (5) Does neuroticism confound the association between work exposures and mental distress? Workers on six shift-schedules answered a questionnaire (1,471 of 2,628 employees). Psychological and social work factors were measured by QPSNordic, mental distress was measured by HADS and neuroticism was measured by EPQ. The results showed 1) No differences in mental distress between workers in different shift schedules, 2) Revolving-shift workers reported higher neuroticism compared to day workers, 3) Swing-shift workers and revolving-shift workers reported lower job control compared to permanent-night and -day workers, 4) Job demands and role conflict were associated with more mental distress. Job control, role clarity, support, and leadership were associated with lower mental distress, 5) Neuroticism influenced the relationship between psychosocial work factors and mental distress. The present study did not find differences in mental distress between shift schedules. Job characteristics may be contributing factors when determining health effects of shift work.