Shift work disorder in nurses--assessment, prevalence and related health problems

Impact of hypnotics use on daytime function and factors associated with usage by female shift work nurses

OBJECTIVE

We investigated quality of life (QOL) and work performance of hypnotics users, and explored the factors associated with multiple hypnotics usage in shift work nurses.

METHODS

We conducted a questionnaire-based, cross-sectional survey on nurses in university hospitals. We analyzed responses from 1202 nurses; 997 were female shift work nurses (82.9%), including 696 and 281 two- and three-shift workers, respectively.

RESULTS

The rate of hypnotics use was 10% (6.9% were single hypnotic users and 3.1% were multiple hypnotics users). The rate of insomnia did not differ between the single and multiple hypnotics users. However, multiple hypnotics users showed lower QOL, more severe depressive symptoms, and greater frequencies of work-related errors than those using a single hypnotic. A multiple logistic regression analysis revealed that age ≥27 years, presence of depression, eveningness chronotype, and presence of insomnia symptoms were significantly associated with hypnotics use. On the other hand, only the existence of shift work disorder (SWD) was significantly associated with usage of multiple hypnotics.

CONCLUSIONS

The present study suggested that usage of multiple hypnotics is not beneficial for relieving insomnia or for keeping better QOL in shift work nurses. It would be desirable to explore the causal relationship between SWD and multiple hypnotics use in a future longitudinal study.

Nurse perceptions of workplace environment: differences across shifts

AIM

To evaluate whether nurse work shift affected workplace perceptions.

BACKGROUND

Although the importance of work schedule in shaping work attitudes, generally (and specifically for nurses) is well accepted, much work remains in characterising how and why nurses' perceptions might differ across shifts.

METHODS

Using an exploratory study of observational data, we examined whether shift influenced non-supervisory nurses' job perceptions in the Veterans Health Administration All Employee Survey (n = 14057; years 2008, 2010, 2012). The size of differences in item means (95% C.I.) across shifts was evaluated graphically. Using ordinal logistic regression, we accounted for the ordinal outcome variables and controlled for the demographic and survey year effects.

RESULTS

Nurses' perceptions of workplace climate differed across shifts. Items with the greatest differences, consistent across years and analytic methods, involved supervisors and fairness. Night and weekend shift nurse ratings were more negative than for weekday shift nurses.

CONCLUSIONS

Off-shift nurses are less satisfied with work/life balance, their supervisors and especially fairness. Overall satisfaction and turnover intention are not affected to the same extent.

IMPLICATIONS FOR NURSING MANAGEMENT

These results indicate several specific areas that nurse managers can address through workforce support and communication.

Psychosocial stress in nurses with shift work schedule is associated with functional gastrointestinal disorders

Background/Aims

The aim of this study was to investigate the role of psychosocial problems and their associations with rotating shift work in the development of functional gastrointestinal disorders.

Methods

In this cross-sectional observation study, survey was administered to nurses and nurse assistants in a referral hospital. In addition to demographic questions, subjects were asked to complete the Rome III Questionnaire, Pittsburgh Sleep Quality Index and Rome III Psychosocial Alarm Questionnaire.

Results

Responses from 301 subjects were assessed. The overall prevalence of irritable bowel syndrome (IBS) and functional dyspepsia (FD) were 15.0% and 19.6%, respectively. Psychosocial alarms were prevalent in the nursing personnel (74.8% with alarm presence and 23.3% with serious condition) and were more frequent among rotating shift workers (84.7% vs. 74.5% for alarm presence and 28.1% vs. 13.3% for serious condition). The prevalence of both IBS and FD significantly increased with psychosocial risk. An independent risk factor for IBS was serious psychosocial alarm (adjusted odds ratio [aOR], 10.75; 95% confidence interval (CI), 1.30–88.99; P = 0.028). Serious psychosocial alarm was an independent risk factor for FD (aOR, 7.84; 95% CI, 1.98–31.02; P = 0.003). Marriage (aOR 0.30; 95% CI, 0.09–0.93; P = 0.037) was associated with the decreased risk of FD.

Conclusions

The high prevalence of psychosocial stress among nurses who work rotating shifts is associated with the development of functional gastrointestinal disorders.

Predictors of shift work disorder among nurses: a longitudinal study

BACKGROUND

Shift work is associated with sleep problems and impaired health. The main aim of the present study was to explore predictors of developing shift work disorder (SWD) among Norwegian nurses using a longitudinal design.

METHODS

A total of 1533 nurses participating in a survey on shift work, sleep and health responded to questionnaires at baseline and at follow-up about two years later. SWD was defined as problems of excessive sleepiness and/or complaints of insomnia related to the work schedule.

RESULTS AND CONCLUSIONS

There was a significant reduction (p < 0.001) in the prevalence of SWD from baseline to follow-up, from 35.7% to 28.6%. Logistic regression analyses showed significant risks of having SWD at follow-up and the following variables measured at baseline: number of nights worked the last year (OR = 1.01, 95% CI = 1.01-1.02), having SWD (OR = 5.19, 95% CI = 3.74-7.20), composite score on the Epworth Sleepiness Scale (OR = 1.08, 95% CI = 1.04-1.13), use of melatonin (OR = 4.20, 95% CI = 1.33-13.33), use of bright light therapy (OR = 3.10, 95% CI 1.14-8.39), and symptoms of depression measured by the Hospital Anxiety and Depression Scale (OR = 1.07, 95% CI = 1.00-1.14). In addition, leaving night work between baseline and follow-up was associated with a significantly reduced risk of SWD at follow-up (OR = 0.12, 95% CI = 0.07-0.22).

Insomnia in shift work

BACKGROUND

Shift work disorder involves insomnia and/or excessive sleepiness associated with the work schedule. The present study examined the impact of insomnia on the perceived physical and psychological health of adults working on night and rotating shift schedules compared to day workers.

METHODS

A total of 418 adults (51% women, mean age 41.4 years), including 51 night workers, 158 rotating shift workers, and 209 day workers were selected from an epidemiological study. An algorithm was used to classify each participant of the two groups (working night or rotating shifts) according to the presence or absence of insomnia symptoms. Each of these individuals was paired with a day worker according to gender, age, and income. Participants completed several questionnaires measuring sleep, health, and psychological variables.

RESULTS

Night and rotating shift workers with insomnia presented a sleep profile similar to that of day workers with insomnia. Sleep time was more strongly related to insomnia than to shift work per se. Participants with insomnia in the three groups complained of anxiety, depression, and fatigue, and reported consuming equal amounts of sleep-aid medication. Insomnia also contributed to chronic pain and otorhinolaryngology problems, especially among rotating shift workers. Work productivity and absenteeism were more strongly related to insomnia.

CONCLUSION

The present study highlights insomnia as an important component of the sleep difficulties experienced by shift workers. Insomnia may exacerbate certain physical and mental health problems of shift workers, and impair their quality of life.

Demographic and occupational predictors of stress and fatigue in French intensive-care registered nurses and nurses' aides: a cross-sectional study

BACKGROUND

Healthcare workers (HCWs) working in intensive-care units (ICUs) are exposed to high physical and mental demands potentially affecting their health or having repercussions on patient care. Although several studies have explored the links between some aspects of working conditions in hospitals and HCW health, the complex dynamics at play are not fully understood.

OBJECTIVES

This study aimed to explore the impact of a wide array of demographic, employment and organizational factors related to fatigue and stress of French ICU HCWs.

DESIGN AND SETTING

A cross-sectional study was conducted in ICUs of Paris-area hospitals between January 18, 2013 and April 2, 2013. All types of adult ICUs were included (medical, surgical and polyvalent).

PARTICIPANTS

Included in the study were HCWs with patient contact (doctors, residents, registered nurses, nurse's aides and physical therapists). Participation was proposed to all eligible HCWs present during on-site visits. Temporary staff not typically assigned to the given ICU was excluded.

METHODS

Data were collected using an individual questionnaire administered in interviews during day and night shifts (N=682). Stress and fatigue outcomes included the 10-item Perceived Stress Scale (PSS10), the Nottingham Health Profile sleep and energy level rubrics and the current fatigue state at the interview. Multivariate analysis was restricted to nurse and nurse's aide data (n=536).

RESULTS

Doctors and residents reported fewer sleep difficulties but were more likely to report a tired current state. Female gender was associated with higher stress levels and greater fatigue for all outcomes, while greater social support of supervisor or colleagues decreased stress and fatigue. At the organizational level, longer shifts (12 h vs. 8 h) were associated with tired current state and greater sleep difficulties. Personnel on rotating shifts had lower stress and a better current state, while those on night shifts had greater sleep and energy level difficulties.

CONCLUSIONS

Even when controlling for demographic factors, employment and organizational elements remained significantly associated with stress and fatigue outcomes. To improve HCW health it is important to consider simultaneously factors at the individual and organizational level.

Metabolic consequences of sleep and circadian disorders

Sleep and circadian rhythms modulate or control daily physiological patterns with importance for normal metabolic health. Sleep deficiencies associated with insufficient sleep schedules, insomnia with short-sleep duration, sleep apnea, narcolepsy, circadian misalignment, shift work, night eating syndrome, and sleep-related eating disorder may all contribute to metabolic dysregulation. Sleep deficiencies and circadian disruption associated with metabolic dysregulation may contribute to weight gain, obesity, and type 2 diabetes potentially by altering timing and amount of food intake, disrupting energy balance, inflammation, impairing glucose tolerance, and insulin sensitivity. Given the rapidly increasing prevalence of metabolic diseases, it is important to recognize the role of sleep and circadian disruption in the development, progression, and morbidity of metabolic disease. Some findings indicate sleep treatments and countermeasures improve metabolic health, but future clinical research investigating prevention and treatment of chronic metabolic disorders through treatment of sleep and circadian disruption is needed.

Short rest periods between work shifts predict sleep and health problems in nurses at 1-year follow-up

OBJECTIVES

We investigated whether the number of work shifts separated by less than 11 hours (quick returns) at baseline (T1) could predict health problems in nurses at 1-year follow-up (T2).

METHODS

1224 nurses responded to a questionnaire-based survey in 2009 (T1) and 2010 (T2). Crude and adjusted logistic regression analyses were completed to assess the association between annual number of quick returns at T1 and the following outcome variables at T2: shift work disorder (SWD), excessive sleepiness (Epworth Sleepiness Scale), pathological fatigue (Chalder Fatigue Scale) and anxiety and depression (Hospital Anxiety and Depression Scale), while controlling for age, gender, the corresponding outcome variable at T1, number of night shifts at T1, change in number of quick returns and number of night shifts from T1 to T2.

RESULTS

The adjusted analyses showed that the annual number of quick returns at T1 predicted the occurrence of SWD (OR=1.01, 95% CI 1.00 to 1.01) and pathological fatigue (OR=1.01, 95% CI 1.00 to 1.01) at T2. A decreased number of quick returns from T1 to T2 entailed a reduced risk of pathological fatigue (OR=0.67, 95% CI 0.45 to 0.99) at T2. There was no association between quick returns at T1 and excessive sleepiness, anxiety or depression at T2 in the adjusted analyses.

CONCLUSIONS

This is the first longitudinal study investigating the associations between quick returns and future health problems. Quick returns increased the risk of SWD and pathological fatigue at 1-year follow-up. Reducing the number of quick returns from 1 year to the next was related to reduced risk of developing pathological fatigue.

Prevalence of depression and its relationship with work characteristics in a sample of public workers

Occupation is a fundamental right, enabling social interaction and financial support for the individual. However, it is an undeniable source of stress, with consequences for physical and mental health. The prevalence of depression and somatic complaints were assessed in 1,013 public workers using the Beck Depression Inventory and a questionnaire investigating for the presence of somatic problems designed by the research team. The results were related to demographic characteristics, history of previous depressive episodes, work schedule (day work, night and day rotating shift work, day rotating shift work), and duration of current work schedule. There were more cases of moderate depression in the day rotating shift workers (84%) than in those working at night (83%). More women had mild or moderate depression than men (22% and 4% versus 10% and 3%, respectively). Severe depression was found only in men. Nearly 10% of depressed individuals reported previous depressive episodes. A link between depression and somatic complaints was also found. In particular, 59% of depressed subjects reported gastrointestinal complaints and 41% did not (P<0.001). In conclusion, the occurrence of depressive symptoms could be facilitated by occupation. A history of depressive symptoms should not be neglected, given the risk of recurrence. Somatic complaints could represent a "wake-up call" regarding depression. Global assessment and effective support are fundamental for promotion of a better quality of life in the at-risk category of workers.

Personality factors predict sleep-related shift work tolerance in different shifts at 2-year follow-up: a prospective study

OBJECTIVES

The aim of the present study was to investigate whether the personality variables morningness, flexibility, languidity and hardiness could predict sleep-related shift work tolerance for the day, evening and night shifts, respectively.

DESIGN

Prospective study design with questionnaires administered in winter 2008/2009 (wave 1) and 2 years later in spring 2011 (wave 3).

SETTING

Different healthcare institutions in Norway.

PARTICIPANTS

The sample comprised in all 700 nurses working a three-shift rotating schedule.

PRIMARY AND SECONDARY OUTCOME MEASURES

The personality variables were assessed at wave 1, as were the demographic, lifestyle and work-related variables. Sleep-related shift work tolerance, assessed at wave 3, was measured separately for the day, evening and night shifts with the Bergen Shift Work Sleep Questionnaire.

RESULTS

Morningness was positively associated with sleep-related day shift tolerance (p<0.001). Flexibility was positively associated with sleep-related tolerance for the evening as well as night shift (p<0.001). Furthermore, languidity was negatively associated with sleep-related shift tolerance for the day, evening and night shifts (p<0.001, <0.01, <0.05, respectively). Hardiness was positively associated with sleep-related tolerance for the day, evening and night shifts (p<0.001, <0.01, <0.05, respectively). Age was negatively associated with sleep-related shift tolerance for the day, night (p<0.01) and evening shifts (p<0.001).

CONCLUSIONS

The findings indicate that hardiness and languidity predict sleep-related shift work tolerance across all shift types among shift working nurses. The effects of flexibility and morningness seem to depend on the shift schedule. By and large, our results are in accordance with previous studies; however, we have now demonstrated the prospective importance of personality in relation to sleep-related shift work tolerance across different shifts.

Insomnia, excessive sleepiness, excessive fatigue, anxiety, depression and shift work disorder in nurses having less than 11 hours in-between shifts

Study objective

To assess if less than 11 hours off work between work shifts (quick returns) was related to insomnia, sleepiness, fatigue, anxiety, depression and shift work disorder among nurses.

Methods

A questionnaire including established instruments measuring insomnia (Bergen Insomnia Scale), sleepiness (Epworth Sleepiness Scale), fatigue (Fatigue Questionnaire), anxiety/depression (Hospital Anxiety and Depression Scale) and shift work disorder was administered. Among the 1990 Norwegian nurses who participated in the study; 264 nurses had no quick returns, 724 had 1–30 quick returns and 892 had more than 30 quick returns during the past year. 110 nurses did not report the number of quick returns during the past year. The prevalence of insomnia, excessive sleepiness, excessive fatigue, anxiety, depression and shift work disorder was calculated within the three groups of nurses. Crude and adjusted logistic regression analyses were performed to assess the relation between quick returns and such complaints.

Results

We found a significant positive association between quick returns and insomnia, excessive sleepiness, excessive fatigue and shift work disorder. Anxiety and depression were not related to working quick returns.

Conclusions

There is a health hazard associated with quick returns. Further research should aim to investigate if workplace strategies aimed at reducing the number of quick returns may reduce complaints among workers.

Associations between night work and anxiety, depression, insomnia, sleepiness and fatigue in a sample of Norwegian nurses

Background

Night work has been reported to be associated with various mental disorders and complaints. We investigated relationships between night work and anxiety, depression, insomnia, sleepiness and fatigue among Norwegian nurses.

Methods

The study design was cross-sectional, based on validated self-assessment questionnaires. A total of 5400 nurses were invited to participate in a health survey through the Norwegian Nurses' Organization, whereof 2059 agreed to participate (response rate 38.1%). Nurses completed a questionnaire containing items on demographic variables (gender, age, years of experience as a nurse, marital status and children living at home), work schedule, anxiety/depression (Hospital Anxiety and Depression Scale), insomnia (Bergen Insomnia Scale), sleepiness (Epworth Sleepiness Scale) and fatigue (Fatigue Questionnaire). They were also asked to report number of night shifts in the last 12 months (NNL). First, the parameters were compared between nurses i) never working nights, ii) currently working nights, and iii) previously working nights, using binary logistic regression analyses. Subsequently, a cumulative approach was used investigating associations between NNL with the continuous scores on the same dependent variables in hierarchical multiple regression analyses.

Results

Nurses with current night work were more often categorized with insomnia (OR = 1.48, 95% CI = 1.10–1.99) and chronic fatigue (OR = 1.78, 95% CI = 1.02–3.11) than nurses with no night work experience. Previous night work experience was also associated with insomnia (OR = 1.45, 95% CI = 1.04–2.02). NNL was not associated with any parameters in the regression analyses.

Conclusion

Nurses with current or previous night work reported more insomnia than nurses without any night work experience, and current night work was also associated with chronic fatigue. Anxiety, depression and sleepiness were not associated with night work, and no cumulative effect of night shifts during the last 12 months was found on any parameters.

Exposure to bullying behaviors as a predictor of mental health problems among Norwegian nurses: results from the prospective SUSSH-survey

BACKGROUND

The relationship between workplace bullying and mental health problems are well documented in previous cross-sectional studies, but knowledge on how this relationship develops over time is still scarce.

OBJECTIVES

The aim of this study was to explore the prospective relationship between exposure to bullying behaviors at baseline, and increased symptoms of mental health problems (anxiety, depression, fatigue) one year later. Furthermore, the reverse relationship was investigated.

DESIGN

This is a prospective longitudinal study, where members of the Norwegian Nurses Organization answered identical questions regarding workplace bullying and mental health problems, at baseline (2008-2009) and follow-up (2010).

PARTICIPANTS

Altogether, 1582 nurses completed both questionnaires.

RESULTS

Hierarchical regression analyses indicated that exposure to bullying behaviors at baseline predicted subsequent increased symptoms of anxiety and fatigue, after adjusting for baseline symptoms of anxiety and fatigue respectively, age, gender, night work and job demands. Moreover, symptoms of anxiety, depression and fatigue at baseline predicted increased exposure to bullying behaviors one year later, after adjusting for exposure to bullying behaviors at baseline, age, gender, night work and job demands.

CONCLUSION

In this study we find support for a reciprocal relationship between exposure to bullying behaviors and symptoms of anxiety and fatigue, respectively. Thus, the results may indicate a vicious circle where workplace bullying and mental health problems mutually affect each other negatively.

The effectiveness of light/dark exposure to treat insomnia in female nurses undertaking shift work during the evening/night shift

STUDY OBJECTIVES

The present study investigated whether bright light exposure during the first half of the evening/night shift combined with light attenuation in the morning is effective in improving sleep problems in nurses undertaking rotating shift work who suffer from clinical insomnia.

METHODS

This was a prospective, randomized control study. The Insomnia Severity Index (ISI) and the Hospital Anxiety Depression Scale (HADS) were used to evaluate insomnia and anxiety/depression severity, respectively. Female hospital nurses on rotating shifts during the evening or night shift with an ISI score > 14 were enrolled. Subjects in the treatment group (n = 46) were exposed to bright light at 7,000-10,000 lux for ≥ 30 minutes. Exposure was continued for at least 10 days during 2 weeks, and the subjects avoided daytime outdoor sun exposure after work by wearing dark sunglasses. Subjects in the control group (n = 46) were not exposed to bright light, but also wore sunglasses after work. Statistical analyses were performed to examine group differences and differences across treatments.

RESULTS

After treatment, the treatment group showed significant improvements in the ISI score and the HADS total and subscale scores as compared with pre-treatment. The ISI, HADS, and subscales of the HADS scores were significantly improved across treatments in the treatment group as compared with the control group.

CONCLUSIONS

The design of this study is easy to put into practice in the real world. This is the first study to document that a higher intensity and briefer duration of bright light exposure during the first half of the evening/night shift with a daytime darkness procedure performed in rotating shift work female nurses suffering from clinical insomnia could improve their insomnia, anxiety, and depression severity.

Effects of shift and night work in the offshore petroleum industry: a systematic review

Shift and night work are associated with several negative outcomes. The aim of this study was to make a systematic review of all studies which examine effects of shift and night work in the offshore petroleum industry, to synthesize the knowledge of how shift work offshore may affect the workers. Searches for studies concerning effects on health, sleep, adaptation, safety, working conditions, family- and social life and turnover were conducted via the databases Web of Knowledge, PsycINFO and PubMed. Search was also conducted through inspection of reference lists of relevant literature. We identified studies describing effects of shift work in terms of sleep, adaptation and re-adaptation of circadian rhythms, health outcomes, safety and accidents, family and social life, and work perceptions. Twenty-nine studies were included. In conclusion, the longitudinal studies were generally consistent in showing that adaptation to night work was complete within one to two weeks of work, while re-adaptation to a daytime schedule was slower. Shift workers reported more sleep problems than day workers. The data regarding mental and physical health, family and social life, and accidents yielded inconsistent results, and were insufficient as a base for drawing general conclusions. More research in the field is warranted.

Re-examining "temporal niche"

The circadian system temporally organizes physiology and behavior throughout the 24-h day. At the core of this organization lies a network of multiple circadian oscillators located within the central nervous system as well as in virtually every peripheral organ. These oscillators define a 24-h temporal landscape of mutually interacting circadian rhythms that is known as the temporal niche of a species. This temporal niche is constituted by the collective phases of all biological rhythms emerging from this multi-oscillatory system. We review evidence showing that under different environmental conditions, this system can adopt different harmonic configurations. Thus, the classic chronobiological approach of searching for "the" circadian phase of an animal-typically by studying circadian rhythms of locomotor activity-represents a narrow look into the circadian system of an animal. We propose that the study of hormonal rhythms may lead to a more insightful assessment of a species' temporal niche.

Factors associated with shift work disorder in nurses working with rapid-rotation schedules in Japan: the nurses' sleep health project

Workers who meet the criteria for shift work disorder (SWD) have elevated levels of risk for various health and behavioral problems. However, the impact of having SWD on shiftworkers engaged in rapid-rotation schedules is unknown. Moreover, the risk factors for the occurrence of SWD remain unclear. To clarify these issues, we conducted a questionnaire-based, cross-sectional survey on a sample of shiftworking nurses. Responses were obtained from 1202 nurses working at university hospitals in Tokyo, Japan, including 727 two-shift workers and 315 three-shift workers. The questionnaire included items relevant to age, gender, family structure, work environment, health-related quality of life (QOL), diurnal type, depressive symptoms, and SWD. Participants who reported insomnia and/or excessive sleepiness for at least 1 mo that was subjectively relevant to their shiftwork schedules were categorized as having SWD. The prevalence of SWD in the sampled shiftworking nurses was 24.4%; shiftworking nurses with SWD showed lower health-related QOL and more severe depressive symptoms, with greater rates of both actual accidents/errors and near misses, than those without SWD. The results of logistic regression analyses showed that more time spent working at night, frequent missing of nap opportunities during night work, and having an eveningness-oriented chronotype were significantly associated with SWD. The present study indicated that SWD might be associated with reduced health-related QOL and decreased work performance in shiftworking nurses on rapid-rotation schedules. The results also suggested that missing napping opportunities during night work, long nighttime working hours, and the delay of circadian rhythms are associated with the occurrence of SWD among shiftworking nurses on rapid-rotation schedules.

Circadian rhythm abnormalities

PURPOSE

This article reviews the recent advances in understanding of the fundamental properties of circadian rhythms and discusses the clinical features, diagnosis, and treatment of circadian rhythm sleep disorders (CRSDs).

RECENT FINDINGS

Recent evidence strongly points to the ubiquitous influence of circadian timing in nearly all physiologic functions. Thus, in addition to the prominent sleep and wake disturbances, circadian rhythm disorders are associated with cognitive impairment, mood disturbances, and increased risk of cardiometabolic disorders. The recent availability of biomarkers of circadian timing in clinical practice has improved our ability to identify and treat these CRSDs.

SUMMARY

Circadian rhythms are endogenous rhythms with a periodicity of approximately 24 hours. These rhythms are synchronized to the physical environment by social and work schedules by various photic and nonphotic stimuli. CRSDs result from a misalignment between the timing of the circadian rhythm and the external environment (eg, jet lag and shift work) or a dysfunction of the circadian clock or its afferent and efferent pathways (eg, delayed sleep-phase, advanced sleep-phase, non-24-hour, and irregular sleep-wake rhythm disorders). The most common symptoms of these disorders are difficulties with sleep onset and/or sleep maintenance and excessive sleepiness that are associated with impaired social and occupational functioning. Effective treatment for most of the CRSDs requires a multimodal approach to accelerate circadian realignment with timed exposure to light, avoidance of bright light at inappropriate times, and adherence to scheduled sleep and wake times. In addition, pharmacologic agents are recommended for some of the CRSDs. For delayed sleep-phase, non-24-hour, and shift work disorders, timed low-dose melatonin can help advance or entrain circadian rhythms; and for shift work disorder, wake-enhancing agents such as caffeine, modafinil, and armodafinil are options for the management of excessive sleepiness.

Shift work disorder in a random population sample--prevalence and comorbidities

Few studies have investigated the presence of shift work disorder (SWD) in the general community. We addressed many of the limitations in this literature and present new findings. SWD has been treated as an ‘all or none’ construct but we propose the need to consider the ‘severity’ of the disorder. Using random digit dialling, we randomly recruited 1163 participants. Participants completed an extensive battery of scales and questions concerning work, health and individual differences. Three questions based on the criteria from the International Classification for Sleep Disorders were used to categorise participants with SWD (n = 176). In addition, we asked participants whether SWD interfered with aspects of their life and high ratings were used to define severe shift work disorder (SSWD). The prevalence of SWD was 32.1% among night workers and 10.1% in day workers (p<.001). SSWD was present in 9.1% of night workers and 1.3% of day workers (p<.001). Adjusted logistic regression analyses found significant associations between SWD and night work (OR  = 3.35, CI 2.19-5.12), weekly work hours (OR  = 1.02, CI 1.00–1.04), short sleep (≤6 h; OR  = 2.93, CI 1.94–4.41), languidity (OR  = 1.11, CI 1.06–1.16) and resilience (OR  = 0.56, CI 0.43–0.81). Night work, short sleep, languidity, and hypertension were significantly associated with SSWD. Overall, participants with SSWD slept 0.80 h less than other participants (p<.001). Night work, short sleep and languidity were associated with both SWD and SSWD. Day workers with SWD symptoms reported significantly shorter sleep duration, higher levels of languidity and worked longer working hours compared to day workers without SWD.

The effect of shift length on fatigue and cognitive performance in air medical providers

OBJECTIVE

To employ a battery of previously validated surveys and neuropsychological tests to compare changes in fatigue and cognitive abilities of air medical providers after 12- and 24-hour shifts.

METHODS

A convenience sample of 34 flight nurses and flight paramedics employed by one air medical service completed the Pittsburgh Sleep Quality Index (PSQI) and the Chalder Fatigue Questionnaire (CFQ) to determine fatigue before and after 12-hour (n = 16) and 24-hour (n = 19) shifts. A battery of neuropsychological tests, including the University of Southern California Repeatable Episodic Memory Test (USC-REMT), Paced Auditory Serial Addition Test (PASAT), Trail Making Test (TMT), and Stroop Color-Word Test were administered before and after the shift to measure changes in cognition. We compared the change in scores stratified by shift length using t-tests, Wilcoxon signed-rank test, and Fisher's exact test.

RESULTS

Participants in the 12- and 24-hour shift groups were aged 36 ± 8 years (12-hour shifts) and 39 ± 6 years (24-hour shifts) (mean ± standard deviation) and were preponderantly male (62% 12-hour shifts; 63%, 24 hour shifts). The PSQI scores identified 50% of both 12-hour and 24-hour shift subjects as having poor sleep quality. Preshift fatigue was described as a median 2/10 (interquartile range [IQR] = 2-4) and fatigue declined by the end of the shift to a median 1/10 [IQR = 1-2], p = 0.006. Providers averaged 6.8 hours of sleep during 24-hour shifts and 1 hour of sleep during 12-hour shifts. Changes in cognitive scores did not differ between groups.

CONCLUSIONS

This study identified no changes in cognitive performance following 12- and 24-hour shifts in air medical providers. This suggests that 24-hour shifts in an air medical service with low to moderate utilization do not have a detrimental effect on cognition as measured by this test battery, and are comparable to 12-hour shifts in terms of impact on cognitive function.