Group Of Shift Workers Research Articles

The comparison of sleep disorders among shift workers and non-shift workers in doorod hospital

Introduction Health workers ability to provide high quality care can be adversely affected by many factors such as sleep deprivation associated with shift work. The aim of this study was comparing sleep problems among shift workers and non shift workers. Materials and methods At first we collected demographic data from the hospital workers. We divided 153 Volunteers into shift worker and non shift worker groups. They completed the Global Sleep Assessment Questionnaire for sleep problems. The results were analyzed by z -test and x 2 , in SPSS ( V,16). Results Shift workers suffered significantly from daily sleeping ( p = 0/001), daily dysfunction due to sleepiness ( p = 0/001), insufficient sleep ( p = 0/001) and sleep apnea ( p = 0/001) as compared with non-shift workers. Conclusion This study showed that there is relation between shift work and sleep problems such as daily sleepiness and apnea. Those sleep problems can affect clinical performance and may be an important factor in patient safety and the health worker’s well being. Acknowledgement Acknowledgment to the personnel of Shahid Rajaie Hospital for their cooperation.

The influence of shift work on cognitive functions and oxidative stress

Shift work influences health, performance, activity, and social relationships, and it causes impairment in cognitive functions. In this study, we investigated the effects of shift work on participants' cognitive functions in terms of memory, attention, and learning, and we measured the effects on oxidative stress. Additionally, we investigated whether there were significant relationships between cognitive functions and whole blood oxidant/antioxidant status of participants. A total of 90 health care workers participated in the study, of whom 45 subjects were night-shift workers. Neuropsychological tests were administered to the participants to assess cognitive function, and blood samples were taken to detect total antioxidant capacity and total oxidant status at 08:00. Differences in anxiety, depression, and chronotype characteristics between shift work groups were not significant. Shift workers achieved significantly lower scores on verbal memory, attention–concentration, and the digit span forward sub-scales of the Wechsler Memory Scale-Revised (WMS-R), as well as on the immediate memory and total learning sub-scales of the Auditory Verbal Learning Test (AVLT). Oxidative stress parameters were significantly associated with some types of cognitive function, including attention–concentration, recognition, and long-term memory. These findings suggest that night shift work may result in significantly poorer cognitive performance, particularly working memory.

Characteristics of Menstrual Cycle in Shift Workers

Background:In this study, the characteristics of menstrual cycle in shift workers employed in the pharmaceutical industry are investigated.Method:This study was conducted in a pharmaceutical industrial complex in Tehran in 2012. 406 female workers in packaging units were studied on the menstrual cycle characteristics. The studied workers were divided into two groups of shift workers and non-shift workers and were compared in terms of the frequency of menstrual disorder (short-term cycle, long-term cycle, irregular cycle and bleeding during menstrual cycle) as well as hormonal values (FSH, LH, TSH, and Prolactin).Results:The odds ratio (OR) for menstrual disorder in the shift workers was 5.54 (95% CI=2.78-11.02) compared to the non-shift workers. The mean difference of hormonal values (except prolactin) between shift workers and non-shift workers was not significant (P> 0.05).Conclusion:This study suggests that shift work may disrupt the menstrual cycle.

The Association between Shift Work and the Metabolic Syndrome in Female Workers

ObjectiveThis study aimed to determine identify any association between shift work and the metabolic syndrome by comparing the prevalence rates of the metabolic syndrome in shift work groups and daytime work groups for female workers.MethodsBased on data from health examinations carried out from April to December of 2012, we selected as our subjects 254 female workers from the Daegu area Dyeing Industrial Complex. We diagnosed the metabolic syndrome using the examination results, and information about age, whether or not they did shift work, job type, smoking habits, drinking habits, exercise habits, and past medical history was collected through self-administered questionnaire surveys and face-to-face interviews. The variables found in a univariate analysis to be significant in the occurrence of the metabolic syndrome - age, drinking habits, exercise habits, and shift work - were included in a logistic regression analysis of the risk of the metabolic syndrome for female workers.ResultsThe prevalence rates of the metabolic syndrome for the total group of study subjects was 11.8%, for daytime workers was 2.8%, and for shift workers was 15.3%. A logistic regression analysis of the odds of the metabolic syndrome for female workers was conducted that included factors associated with the occurrence of the metabolic syndrome: age, drinking habits, exercise habits, and shift work. The results revealed that the odds ratio of the metabolic syndrome in the shift work group, 6.30 (95% CI 1.24-32.15), was significantly higher when compared with the daytime work group.ConclusionShift work appears to have an association with the metabolic syndrome in female workers. Accordingly, we believe that the attention of government agencies and business owners is needed together with the individual practice of health behaviors to manage the metabolic syndrome for the prevention of cardiovascular disease in female shift workers.

Adipokine Levels Are Altered by Shiftwork: A Preliminary Study

Shiftwork is often associated with metabolic diseases, and in the past few years, several cytokines have been postulated to contribute to various diseases, including insulin resistance. The aim of this study was to compare the concentrations of adiponectin, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in samples of young adult men exposed to a fixed (i) night shift (n = 9), working from 22:00 to 06:00 h; (ii) early morning shift (n = 6), working from 06:00 to 14:00 h; and (iii) day shift (n = 7), working from 08:00 to 17:00 h. The fixed night-shift and early-morning-shift samples were considered collectively as a shiftworker group given their work times. Blood samples were collected during the regular working day at 4-h intervals over the course of 24 h, thus totaling six samples. Morphological and physical activity parameters did not differ between the three groups. Total energy intake was lowest on the early morning shifts (p < .03). Both shiftworker groups ingested a significantly higher percentage of fat (p < .003) and a lower percentage of carbohydrate (p < .0005) than the day group. The early morning group had a lower mean 24-h level of adiponectin than the other two groups (p = .016), and both the early morning and night groups exhibited higher mean 24-h levels of TNF-α than the day group (p = .0001). The 24-h mean levels of IL-6 did not differ significantly between the groups (p = .147). None of the groups exhibited a significant circadian effect on adiponectin (p = .829), TNF-α (p = .779), or IL-6 (p = .979) levels. These results indicate that individuals who are enrolled in shiftwork are susceptible to alterations in the secretion of cytokines that are involved in insulin resistance and cardiovascular disease, both of which are known to affect this population. (Author correspondence: tmello@demello.net.br)

The relationship between occupational stress and serum glycosylated hemoglobin A1c level

To explore the relationship between occupational stress and serum glycosylated hemoglobin A1c (HbA1c) level. A cross-sectional epidemiological study was conducted in 115 dispatchers. The occupational stressors, personality, occupational strain and coping with stress were measured using Occupational Stress Instrument. Serum HbA1c levels were measured by stratigraphic analysis of cation exchange resin. Serum HbA1c level (6.63% ± 1.93%) in the shiftwork group was significantly higher than that (5.73% ± 1.57%) in the daily relay work group (P < 0.05). Spearman correlation analyses showed the positive correlation between type A behavior and serum HbA1c level (r = 0.221), the negative correlation between organizational commitment and serum HbA1c level (r = -0.218). Variance analyses revealed that serum HbA1c levels among high, middle and low job requirement groups and job control groups were significantly different (P < 0.05). There were significant differences of serum HbA1c levels among different type A behavior, internal control, susceptibility of stress and organizational commitment groups (P < 0.05). Stepwise regression analyses indicated that shiftwork affects obviously serum HbAlc level, internal control and job future were the predictors of serum HbA1c level (R2 = 0.082). Serum HbA1c may be a potential biomarker in field investigation of the effects of occupational stress.

The Effects of Age and Shiftwork on Perceived Sleep Problems

With workforces in industrialized countries getting older, the study examined how shiftworking affects sleep in later life. Longitudinal data were collected in 1996, 2001, and 2006 from a large sample of employees who were 32, 42, 52, and 62 years old in 1996. Effects of shiftwork were most apparent in middle-aged participants, becoming less apparent in later years when people tended to leave shiftwork. Nevertheless, a group of younger former shiftworkers reported more sleep problems than those who had never worked shifts. Giving up shiftwork offset a trend for sleep problems to accumulate over time, with the net result of no change in sleep problems after cessation of shiftwork. Poor sleep quality is a temporary consequence of shiftwork for some, whereas for others it is a cause of shiftwork intolerance.

Obstructive sleep apnea in shift workers

Objective In modern society, the number of people working night shifts is increasing. The aim of the study was to investigate effects of shift work on obstructive sleep apnea syndrome (OSAS) and oxygen desaturation index (ODI) during daytime and nighttime sleep in patients with OSAS. Methods Twenty-nine male and two female shift workers (SW) with OSAS were investigated. Their mean age was 47 ± 10 years, BMI 32 ± 4 kg/m 2. The control group consisted of 10 male patients with OSAS, matched for age, BMI, and hours of night sleep, not working on shifts. Nocturnal and diurnal after night shift or sleep deprivation polysomnographies (PSG) were performed in all subjects. Results Comparison of diurnal and nocturnal PSG recordings in the SW group demonstrated a significantly higher AHI in diurnal PSG after the night shift vs. nocturnal PSG (50 ± 27 vs. 32 ± 22, P < 0.05). During daytime sleep SW OSAS patients demonstrated higher AHI than sleep-deprived controls (49.7 ± 26.6 vs. 30.1 ± 21.9, P < 0.05) and higher ODI (44.1 ± 25.1 vs. 21.6 ± 18.5, P < 0.05). Conclusions Significantly higher severity of OSAS during daytime sleep after night shift may intensify unfavorable health effects of OSAS. Patients with OSAS if not effectively treated should avoid nighttime work.

Shiftwork locus of control effects in police officers.

Personality and experientially-based differences are suggested to moderate the negative effects of shiftworking. This investigation was one of a series of studies aimed at examining the relationship between internal locus of control (internality) and commonly reported outcomes of exposure to shiftworking. The study concentrated on whether or not shiftwork-specific internality appeared to be associated with better experiences for two groups of shiftworkers on different shift rotas. The Shiftwork Locus of Control (SHLOC) scale was completed by each group along with a range of outcome measures (including: sleep disturbance, alertness on shift, psychological well-being, disturbance of social and family life, and fatigue). The analyses controlled for for age, shiftwork experience and years of service effects. The results showed that for the majority of outcome variables, the higher internality was associated with significantly lower levels of shiftwork problems, especially when compared to the low internality group. The findings of this study further support the use of shiftwork-specific locus of control in shiftwork research as an indicator of potentially better tolerance, and possibly as part of an occupational health monitoring process to aid the targeting of interventions.

EPIGENETIC EFFECTS OF SHIFTWORK ON BLOOD DNA METHYLATION

In the present study, the authors investigated the effects of shiftwork exposure on DNA methylation using peripheral blood DNA from subjects working in two chemical plants in Northern Italy. The investigation was designed to evaluate (a) DNA methylation changes in Alu and long interspersed nuclear element-1 (LINE-1) repetitive elements as a surrogate of global methylation and (b) promoter methylation of glucocorticoid receptor (GCR), tumor necrosis factor alpha (TNF-α), and interferon-gamma (IFN-γ). One hundred and fifty white male workers (mean ± SD: 41.0 ± 9 yrs of age) were examined: 100 3 × 8 rotating shiftworkers (40.4 ± 8.7 yrs of age) and 50 day workers (42.2 ± 9.4 yrs of age). The authors used bisulfite-pyrosequencing to estimate repetitive elements and gene-specific methylation. Multiple regression analysis, adjusted for age, body mass index (BMI), and job seniority, did not show any significant association between the five DNA methylation markers and shiftwork. However, job seniority, in all subjects, was significantly associated with Alu (β = −0.019, p = .033) and IFN-γ (β = −0.224, p < .001) methylation, whereas TNF-α methylation was inversely correlated with age (β = −0.093, p < .001). Considering only shiftworkers, multiple regression analysis, adjusted for age, BMI, and job seniority, showed a significant difference between morning and evening types in TNF-α methylation (mean morning type [MT] 11.425 %5mC versus evening type [ET] 12.975 %5mC; β = 1.33, p = .022). No difference was observed between good and poor tolerance to shiftwork. Increasing job seniority (<5, 5–15, >15 yrs) was associated with significantly lower Alu (β = −0.86, p = .006) and IFN-γ methylation (β = −6.50, p = .007) after adjustment for age, BMI, and morningness/eveningness. In addition, GCR significantly increased with length of shiftwork (β = 3.33, p = .05). The data showed alterations in blood DNA methylation in a group of shiftworkers, including changes in Alu repetitive elements methylation and gene-specific methylation of IFN-γ and TNF-α promoters. Further studies are required to determine the role of such alterations in mediating the effects of shiftwork on human health. (Author correspondence: giovanni.costa@unimi.it)

An Occupational Health Study of Emergency Physicians in Japan: Health Assessment by Immune Variables (CD4, CD8, CD56, and NK Cell Activity) at the Beginning of Work

This study was conducted to evaluate the occupational health of Japanese physicians in emergency medicine. Subjects participating in this study were eighty-nine physicians working at 12 medical facilities (10 critical care emergency centers) in Japan. Participants were asked to complete a questionnaire of work conditions and to provide blood samples for immune variable measurements (CD4, CD8, CD56 and natural killer cell (NK cell) activity) before commencing their work. The data collected from seventy-four of 89 participating physicians were analyzed. The traditional work group comprised of 39 emergency physicians, who were significantly overworked compared to other two groups: the shift work group and the day work group. Among these three groups, no immune variable was significantly different except lymphocyte, number of CD4, and NK cell activity; and the NK cell activity of the shift work group was significantly lower than those of the traditional work group (p<0.01) and the day work group (p<0.01) in terms of Bonferroni's multiple comparison, probably due to circadian rhythm. It was indicated that NK cell activity was significantly lower in samples collected at night versus in the morning (OR=8.34, 95%CI: 1.95-35.6, p<0.01) through multiple logistic regression analyses. NK cell activity was significantly lower in individuals taking 0-3 days off per month, as compared to those taking 4 or more days off (OR=4.65, 95%CI: 1.27-17.0, p=0.02), according to multiple logistic regression analyses. Therefore, the low NK cell activity appears to have reflected the extent of fatigue arising from physicians' overwork. Overwork would have been a potential risk for the physicians' health, resulting in a lower quality of Japanese emergency medical services than that which could have been achieved otherwise. This study suggests that it would be better for the Japanese emergency physicians to take 4 or more days off per month for their health and the quality of their services.

Associations of reported bruxism with insomnia and insufficient sleep symptoms among media personnel with or without irregular shift work

BackgroundThe aims were to investigate the prevalence of perceived sleep quality and insufficient sleep complaints, and to analyze whether self-reported bruxism was associated with perceptions of sleep, and awake consequences of disturbed sleep, while controlling confounding factors relative to poor sleep.MethodsA standardized questionnaire was mailed to all employees of the Finnish Broadcasting Company with irregular shift work (n = 750) and to an equal number of randomly selected controls in the same company with regular eight-hour daytime work.ResultsThe response rate in the irregular shift work group was 82.3% (56.6% men) and in the regular daytime work group 34.3% (46.7% men). Self-reported bruxism occurred frequently (often or continually) in 10.6% of all subjects. Altogether 16.8% reported difficulties initiating sleep (DIS), 43.6% disrupted sleep (DS), and 10.3% early morning awakenings (EMA). The corresponding figures for non-restorative sleep (NRS), tiredness, and sleep deprivation (SLD) were 36.2%, 26.1%, and 23.7%, respectively. According to logistic regression, female gender was a significant independent factor for all insomnia symptoms, and older age for DS and EMA. Frequent bruxism was significantly associated with DIS (p = 0.019) and DS (p = 0.021). Dissatisfaction with current work shift schedule and frequent bruxism were both significant independent factors for all variables describing insufficient sleep consequences.ConclusionSelf-reported bruxism may indicate sleep problems and their adherent awake consequences in non-patient populations.

Psychosocial Work Characteristics Predicting Daytime Sleepiness in Day and Shift Workers

Characteristics of work organization other than working time arrangements may contribute importantly to daytime sleepiness. The present study was designed to identify the psychosocial factors at work that predict daytime sleepiness in a sample of day and shift workers. Participants working at a pulp and chemical factory completed an annual questionnaire regarding psychosocial factors at work using the U.S. National Institute for Occupational Safety and Health Generic Job Stress Questionnaire (i.e., quantitative workload, variance in workload, job control, support from supervisor, coworkers, or family/friends, job satisfaction, and depressive symptoms), as well as daytime sleepiness (through the Epworth Sleepiness Scale [ESS]) and sleep disturbances for three years starting in 2002 (response rates, 94.6–99.0%). The present analysis included 55 day workers (11 women) and 57 shift workers (all men) who participated in all three years of the study, worked under the same work schedule throughout the study period, and had no missing data on any of the daytime sleep items. A repeated‐measures analysis of covariance (ANCOVA) was used to test the effects of work schedule (day vs. shift work) and psychosocial factors at work in 2002 on the ESS scores in subsequent years, with sleep duration, insomnia symptoms, chronic diseases, and sleepiness levels at baseline as covariates. Given significant and near‐significant interactions of work schedules with psychosocial factor or study year, the ANCOVA, with the factors of psychosocial work characteristics and study year, was performed by type of work schedule. The results indicated a significant main effect of psychosocial work characteristics (p=0.010, partial ŋ2=0.14) and an almost significant main effect of study year (p=0.067, partial ŋ2=0.06) and interaction between psychosocial work characteristics and study year (p=0.085, partial ŋ2=0.06) for variance in workload among the day work group. The day workers reporting high variance in workload in 2002 exhibited significantly higher ESS scores in 2003 and 2004 than did those reporting low variance in workload. The ANCOVA for the shift work group showed a main effect of psychosocial work characteristics for job satisfaction (p=0.026, partial ŋ2=0.10) and depressive symptoms (p=0.094, partial ŋ2=0.06) with the interaction between psychosocial work characteristics and study year for job satisfaction (p=0.172, partial ŋ2=0.04) and depressive symptoms (p=0.035, partial ŋ2=0.07). The shift workers with low job satisfaction and high symptoms of depression in 2002 showed significantly greater ESS scores in 2003 and/or 2004 than did those with opposite characteristics. These results may suggest a potential predictive value of variance in workload for day workers as well as job satisfaction and depressive symptoms for shift workers with respect to daytime sleepiness. The present findings may imply that redesigning these aspects of work environment would be of help in managing daytime sleepiness.

Effects of Moderate Exercise and Circadian Rhythms on Human Memory

The effects of exercise and circadian rhythms on memory function were explored in a group of shift workers (mean age 32 yrs). A variant of the Auditory-Verbal Learning Test was used to test memory for word lists at 9:30 a.m. and 12:30, 3:30, and 6:30 p.m. in a repeated-measures design. Without exercise there was clear evidence of a circadian rhythm in memory performance, with peak performance occurring at 12:30 and poorest performance at 3:30. A brisk 10-min walk followed by a 15- to 30-min recovery period resulted in significant improvement in memory recall at all time periods except 12:30. The results of the AVLT task suggest an improvement in both working memory and long-term memory performance. Rhythmic changes in serotonin, epinephrine, norepinephrine, and acetylcholine levels all affect cortical arousal and cognitive function. Exercise may have resulted in altered levels of these neurotransmitters, increased glucose, oxygen, or nutrient levels, or from temporary changes in growth hormone or brain-derived neurotropic factor levels resulting in increased synaptogenesis and neurogenesis. The physiological basis of this temporary improvement in memory remains to be determined, but this simple behavioral intervention may have widespread application in improving memory function in all sections of the population including children and the elderly.

Reported bruxism and restless legs syndrome in media personnel with or without irregular shift work

A standardized questionnaire was mailed to all employees of the Finnish Broadcasting Company with irregular shift work (n=750) and to an equal number of randomly selected controls in the same company with regular 8-h daytime work. The questionnaire covered demographic items, employment details, general health experience, physical status, psychosocial status, stress, work satisfaction and performance, tobacco use, bruxism, and restless legs symptoms (RLS). The aim was to investigate among a multiprofessional media personnel the associations between reported bruxism and RLS, while simultaneously controlling the effects of gender, age, tobacco use, shift work, and dissatisfaction with current workshift schedule. The overall response rate was 58.3% (53.7% men). The response rate in the irregular shift work group was 82.3% (56.6% men) and in the regular daytime work group 34.3% (46.7% men). In the bivariate analyses, RLS was more prevalent in workers at either end of the studied age range (p<0.05). Self-reported frequent bruxism was significantly associated with younger age (p<0.05). Females reported RLS (11.4%) slightly more often than males (7.7%) (NS). In logistic regression, frequent bruxism (p<0.05) and older age (p<0.05) were significantly positively associated with RLS. Dissatisfaction with one's current workshift schedule (p<0.05) and RLS (p<0.05) were significantly positively associated with frequent bruxism, while age (p<0.05) was significantly negatively associated. In conclusion, perceived bruxism may be a sign of a stressful situation or dissatisfaction, while RLS as a more stable trait may in itself negatively affect sleep quality and further enhance the problem.

Perceived orofacial pain and its associations with reported bruxism and insomnia symptoms in media personnel with or without irregular shift work

A standardized questionnaire was mailed to all employees of the Finnish Broadcasting Company with irregular shift work (n=750) and to an equal number of randomly selected controls in the same company with regular 8-hour daytime work. The aims were to investigate the prevalence and severity of perceived orofacial pain (Research Diagnostic Criteria for Temporomandibular Disorders Axis II) and to analyze whether current orofacial pain was associated with reported bruxism and insomnia symptoms (Diagnostic and Statistical Manual of Mental Disorders–IV and the International Classification of Sleep Disorders Revised). The response rate in the irregular shift-work group was 82.3% (56.6% men) and in the regular daytime-work group 34.3% (46.7% men). Current orofacial pain was found overall in 19.6%, of which 88.3% had experienced the pain over 6 months. All claimed that their pain fluctuated. No subjects with chronic orofacial pain reported disabling pain, and grades III and IV were not found. Insomnia symptoms and frequent bruxism were significantly more prevalent in chronic pain grade II than in lower grades. According to logistic regression, current orofacial pain was significantly positively associated with frequent bruxism (p<0.001), female gender (p<0.001), and disrupted sleep (p<0.01), and significantly negatively associated with age over 45 years (p<0.01). Our results revealed a clear-cut association between perceived orofacial pain and reported bruxism. The association held with both chronic orofacial pain intensity and current pain. Based on the multivariate analyses, it can be concluded that disrupted sleep and bruxism may be concomitantly involved in the development of orofacial pain.

Quality of life, life satisfaction and happiness in shift- and non-shiftworkers

To investigate the quality of life, life satisfaction, happiness and demands of work in workers with different work schedules. The survey was carried out on professional workers in social care. Some were shiftworkers whose schedule included night shifts (N=311), some were shiftworkers without night shifts (N=207) and some were non-shiftworkers (N=1,210). Surveys were mailed and the response rate was 86%. For the purpose of this study several variables were selected from the Survey: The Quality of Life Profile, which measures importance, satisfaction, control and opportunities in nine domains of life plus measures of happiness, life satisfaction and demands of work. While both groups of shiftworkers, compared to non-shiftworkers, reported needing more physical effort to complete their work, and reported 'being' more physically tired, no differences were found in reports of overall happiness, life satisfaction or total quality of life. However, night-shiftworkers reported greater percentage of time unhappy than the other two groups of workers. In analyses of the quality of life, night-shiftworkers were less satisfied with domains of spiritual 'being' and physical and community 'belonging' than day-shiftworkers and non-shiftworkers. They also reported having fewer opportunities to improve their physical 'being', leisure, and personal growth than the other two groups. Quality of life in specific domains in night-shiftworkers was rated worse than in other groups of workers. Domain-based quality of life assessment gives more information regarding the particular needs of workers than overall or global measures of well-being.

Biological and psychological responses to two rapid shiftwork schedules

This study presents the biological responses to shiftwork in two groups of workers with different shiftwork rotas. Biological responses were studied by recording the heart rate and the changes in the circadian profile of salivary cortisol over 24 h (RIA assays). Various items were recorded through questionnaires aimed at determining self appreciation of sleep quantity, stress, health, satisfaction at work and in private lives. Thirty two male subjects aged from 23 to 56, working for the same company, having given their informed consent, took part in the study. The study was carried out under realistic conditions (at the work place) under the control of an occupational physician. Sixteen day-workers (8 am – 6 pm) served as a reference group. Eight shiftworkers included in alternate schedules (morning M 4 am – 12 am, evening E 12 am – 8 pm, night N 8 pm – 4 am) according to a system M, S, N 3/2, (3 work, 2 rest) and eight according to a system 7/5 (3M/2S/2N/5R, 2/3/2/5, 2/2/3/5) constituted the groups of shiftworkers respectively named 3/2 and 7/5. All subjects had comparable ages and BMIs. Shiftworkers expressed a higher stress level and frequency of health problems and a lower satisfaction at work than the control. Among the three groups, the 7/5 group had the best health and fitness score and was in need of less sleep. Heart rate was not affected by shift work. Conversely, consistent changes appeared in cortisol circadian profiles, the greatest changes appearing for the night shift and among the two groups of shiftworkers, more particularly for the 7/5 group. These changes correlated with self-perceived constraints of work and showed the difficulties of adaptation to shiftwork.

Tolerance to shift work-how does it relate to sleep and wakefulness?

There is limited knowledge as to why some individuals tolerate shift work and others do not. As a consequence of their intolerance, many individuals develop dissatisfaction with their shift schedule. To evaluate if dissatisfaction with one's shift system was related to alterations of the daily pattern of sleep and sleepiness, we followed two groups of shift workers that were either highly satisfied or dissatisfied with their shift schedule, during an entire shift cycle. Thirty-six male and 20 female shift workers were selected according to their satisfaction with their shift schedule. The shift cycle included seven work periods ("triads" of shifts; night shift-afternoon shift-morning shift), with only 8-9 hours off (quick returns) between shifts, but followed by a day off. Sleep length was reduced after night shifts (4.8 h) and afternoon shifts (5.4 h). Sleepiness was increased during all shifts, particularly night shifts. Sleepiness did not accumulate across the shift cycle even though sleepiness was slightly increased directly after the last triad of shifts. There were few significant gender differences. Dissatisfied shift workers reached much higher levels of sleepiness and reported less sufficient sleep, but not objectively poorer or shorter sleep. Amongst dissatisfied workers, this resulted in an increase of sleepiness problems across shifts within the triad of shifts. Dissatisfied workers also had more performance lapses at the end of the night shift. Satisfaction with the shift schedule seems to reflect how well the shift workers were coping with the schedule. It is suggested that the increase of sleep/wake problems within the work period for the dissatisfied shift workers is related to increased sensitivity to curtailed and displaced sleep.

Sleepiness and Sleep Disorders in Shift Workers: A Study on a Group of Italian Police Officers

evaluation of shift-work effect on sleepiness, sleep disorders, and sleep-related accidents in a population of police officers. Aquestionnaire-based survey was used to gather information on age and physical characteristics, working conditions, sleep problems, and accidents. Sleepiness was measured by the Epworth Sleepiness Scale (ESS) while the presence of sleep disorders was evaluated by a score (SDS) drawn from indicators of insomnia, breathing disorders, periodic limb movements and restless legs syndrome, and hypersomnia. The effects of age, gender, body mass index, working conditions, and seniority on ESS, SD score, and accidents were analyzed by linear and logistic regression. The self-administered questionnaires were filled in by police officers in the district of Genoa (Italy). 1,280 police officers: 611 shift workers (SW) and 669 non-shift workers (NSW). N/A. The ESS score was not higher in SW than in NSW, while the SDS was significantly influenced by shift-work conditions and seniority in shift work. The occurrence of sleep-ascribed accidents was significantly increased in the SW group and related to the presence of indicators of sleep disorders. There was evidence for sleep disorders in 35.7% of SW and in 26.3% of NSW. Shift-work conditions and seniority may enhance sleep disorders and may favor sleep-related accidents, but they do not influence ESS score. Stressful conditions could cause sleepiness to be underestimated, or else they might overcome sleepiness. However, our data should alert occupational health physicians for the diagnosis and prevention of possible undetected intrinsic sleep disorders, which could possibly worsen shift workers' health and increase the risk of accidents.