The Impact of Work Schedules and Fatigue on
Workers’ Health and Safety:
An Annotated Bibliography
Annotated Bibliography Created by:
Audrey Altman
Graduate Research Assistant
University of Iowa Labor Center
Note: This material was prepared by the University of Iowa Labor Center for a conference on
health and safety for railroad workers that took place in November, 2011.
Introduction:
This bibliography contains citation information and abstracts for 43 articles related to the study
of the effects of work schedules and fatigue on workers’ health and safety. Special emphasis is
given to the railroad industry. Articles are listed alphabetically by first author and numbered for
easy access. Article information is listed in the following order:
Article title
Journal
Author
Institutional affiliation
Abstract
A subject listing on the following pages will help you find the articles most relevant to your
specific interests. The subject categories are:
Shift work
Irregular work hours/rotating shifts
Extended work hours/overtime
Time off for rest/recovery
Work performance/attentiveness
Accidents/injuries
Fatigue
Health risks
Family/social issues
Railroad workers
Age/older workers
Further Research:
PubMed
http://www.ncbi.nlm.nih.gov/pubmed/
PubMed is a searchable database of medical research, developed and maintained by the National
Center for Biotechnology Information. You can access abstracts of most articles and free full
text of some articles. Many of the articles in this bibliography are listed in PubMed.
MedlinePlus Medical Dictionary
http://www.nlm.nih.gov/medlineplus/mplusdictionary.html
You can use MedlinePlus Medical Dictionary to define medical terminology. This dictionary is
a service of the US National Library of Medicine and Merriam Webster.
1
Article numbers listed by subject:
Shift work (work done outside of normal daylight hours): 1, 5, 8, 11, 14, 15, 17, 18, 23, 30, 31,
35, 36, 37, 39, 40, 41, 42, 43
and work performance/attentiveness: 5, 18, 39
and accidents/injuries: 15, 23
and fatigue: 5, 11, 14, 18, 23, 30, 31, 36, 39, 40, 41, 42, 43
and health risks: 1, 5, 17, 18, 37, 41
and railroad workers: 1, 11, 18, 23, 30, 31, 36, 39, 40, 41, 42, 43
and family/social issues: 18, 30, 35
and age/older workers: 17, 43
Irregular work hours/rotating shifts: 1, 3, 5, 10, 13, 14, 16, 23, 24, 31, 32, 35, 36, 37, 39, 40,
41
and work performance/attentiveness: 13, 39
and accidents/injuries: 10, 13
and fatigue: 3, 5, 13, 14, 16, 23, 24, 31, 32, 36, 39, 40, 41
and health risks: 1, 5, 13, 24, 37, 41
and family/social issues: 24, 35
and railroad workers: 1, 3, 16, 23, 24, 31, 32, 36, 40
and age/older workers: 16
Extended work hours/overtime: 4, 5, 7, 8, 9, 10, 11, 14, 15, 21, 22, 26, 28, 29, 39
and work performance/attentiveness: 4, 5, 7, 39
and accidents/injuries: 7, 8, 9, 10, 15
and fatigue: 4, 5, 7, 11, 14, 39
and health risks: 5, 7, 9, 21, 22, 26, 28, 29
2
and family/social issues: 7
and railroad workers: 11, 39
Time off for rest/recovery: 3, 7, 16, 17, 20, 24, 25, 26, 31, 32, 34, 35, 36, 38, 40
and work performance/attentiveness: 7, 25
and accidents/injuries: 7, 38
and fatigue: 3, 7, 16, 24, 31, 32, 34, 36, 40
and health risks: 7, 17, 20, 24, 26
and family/social issues: 7, 24
and railroad workers: 3, 16, 20, 24, 25, 31, 32, 34, 36, 38, 40
and age/older workers: 16, 17
Work performance/attentiveness: 4, 5, 6, 7, 12, 13, 18, 25, 33, 39
and shift work: 5, 18, 39
and irregular work hours/rotating shifts: 13, 39
and extended work hours/overtime: 4, 5, 7, 39
and time off for rest/recovery: 7, 25
and fatigue: 4, 5, 6, 7, 13, 18, 33, 39
and railroad workers: 6, 12, 18, 25, 33, 39
Accidents/injuries: 6, 7, 8, 9, 10, 12, 13, 15, 23, 38
and shift work: 15, 23
and irregular work hours/rotating shifts: 10, 13
and extended work hours/overtime: 7, 8, 9, 10, 15
and time off for rest/recovery: 7, 38
and fatigue: 6, 7, 13, 23
and railroad workers: 6, 12, 23, 38
Fatigue: 2, 3, 4, 5, 6, 7, 11, 13, 14, 16, 18, 23, 24, 27, 30, 31, 32, 33, 34, 36, 39, 40, 41, 42, 43
3
and shift work: 5, 11, 14, 18, 23, 30, 31, 36, 39, 40, 41, 42, 43
and irregular work hours/rotating shifts: 3, 5, 13, 14, 16, 23, 24, 31, 32, 36, 39, 40, 41
and extended work hours/overtime: 4, 5, 7, 11, 14, 39
and time off for rest/recovery: 3, 7, 16, 24, 31, 32, 34, 36, 40
and work performance/attentiveness: 4, 5, 6, 13, 18, 33, 39
and accidents/injuries: 6, 7, 13, 23
and health risks: 2, 5, 7, 18, 24, 27, 41
and railroad workers: 3, 6, 11, 16, 18, 23, 24, 30, 31, 32, 22, 34, 36, 39, 40, 42, 43
and family/social issues: 18, 24, 30
and age/older workers: 16, 43
Health risks: 1, 2, 5, 7, 9, 13, 17, 18, 19, 20, 22, 21, 24, 26, 27, 28, 29, 37, 41
and shift work: 1, 5, 17, 18, 37, 41
and irregular work hours/rotating shifts: 1, 5, 13, 24, 37, 41
and extended work hours/overtime: 5, 7, 9, 21, 22, 26, 28, 29
and time off for rest/recovery: 7, 17, 20, 24, 26
and fatigue: 2, 5, 7, 13, 18, 24, 27, 41
and railroad workers: 1, 18, 20, 24
and age/older workers: 17
Family/social issues: 7, 18, 19, 24, 30, 35
and shift work: 18, 30, 35
and irregular work hours/rotating shifts: 24, 35
and extended work hours/overtime: 7
and time off for rest/recovery: 7, 24
and fatigue: 7, 18, 24, 30
and railroad workers: 18, 24, 30
4
Railroad workers: 1, 3, 6, 11, 12, 16, 18, 20, 23, 24, 25, 30, 31, 32, 33, 34, 36, 38, 39, 40, 42,
43
and shift work: 1, 11, 18, 23, 30, 31, 36, 39, 40, 41, 42, 43
and irregular work hours/rotating shifts: 1, 3, 16, 23, 24, 31, 32, 36, 40
and extended work hours/overtime: 11, 39
and time off for rest/recovery: 3, 16, 20, 24, 25, 31, 32, 34, 36, 38, 40
and work performance/attentiveness: 6, 12, 18, 25, 33, 39
and accidents/injuries: 6, 12, 23, 38
and fatigue: 3, 6, 11, 16, 18, 23, 24, 30, 31, 32, 22, 34, 36, 39, 40, 42, 43
and health risks: 1, 18, 20, 24
and family/social issues: 18, 24, 30
and age/older workers: 16, 43
Age/older workers: 16, 17, 43
and shift work: 17, 43
and irregular work hours/rotating shifts: 16
and time off for rest/recovery: 16, 17
and fatigue: 16, 43
and health risks: 17
and railroad workers: 16, 43
5
1. Irregularity of working hours in railway workers and types of complaints.
Int Arch Occup Environ Health. 1994;65(6):367-71.
Aguirre A, Foret J.
Service d'Explorations Fonctionnelles, Hôpital Henri-Mondor, Créteil, France.
Seventy-three permanent morning workers, 33 three-shift workers and 43 workers with irregular
working schedules (roster) filled out a questionnaire on sleep, well-being and health complaints.
The frequency of sick leave tended to be smaller in workers in the roster group. However, in this
group health was rated "poor" more often; digestive, respiratory, osteoarticular and nervous
symptoms as well as sleep difficulties were more frequently reported. In the day work and shift
group, ratings of sleep quality were higher on days of rest than on working days but not in the
roster group. This suggests that a worker does not at present get enough non-work days for a
complete short-term recovery. In contrast, the length of sleep reported did not differ among
groups. The gap between the subjective assessment of health and the actual frequency of sick
leave corresponded with the irregularity of the working schedule.
2. Occupational burnout and medically certified sickness absence: a population-based
study of Finnish employees.
J Psychosom Res. 2008 Feb;64(2):185-93.
Ahola K, Kivimäki M, Honkonen T, Virtanen M, Koskinen S, Vahtera J, Lönnqvist J.
Center of Expertise for Work Organizations, Finnish Institute of Occupational Health, Finland.
kirsi.ahola@ttl.fi
OBJECTIVE: Occupational burnout is a common problem in working populations, but its
association with sickness absence is poorly understood. The contribution of occupational burnout
to medically certified sickness absence was examined in a population-based sample of
employees.
METHODS: A representative sample of 3151 Finnish employees aged 30-60 years participated
in a comprehensive health study in 2000-2001, including an assessment of physician-diagnosed
physical illnesses and Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition
(DSM-IV) mental disorders based on the Composite International Diagnostic Interview. Burnout
was measured with the Maslach Burnout Inventory-General Survey. Sickness absences longer
than 9 days in 2000-2001 were extracted from a register of the Social Insurance Institution of
Finland.
RESULTS: The occurrence of medically certified sickness absence was more prevalent among
employees with burnout than among those without burnout. After adjusting for
6
sociodemographic factors and mental and physical disorders, the odds ratio of sickness absence
for severe burnout was 6.9 [95% confidence interval (95% CI)=2.7-17.8] for men and 2.1 (95%
CI=1.1-4.0) for women. Among employees with mental or physical disorders, severe burnout
was associated with a 7.7-fold risk of sickness absence among men and with a 2.6-fold risk
among women. The duration of absence was related to burnout among men with absences, for
whom severe burnout accounted for 52 excess sickness absence days during the 2-year period
after adjusting for sociodemographic factors, mental disorders, and physical illnesses.
CONCLUSIONS: Severe burnout is associated with a substantial excess risk of medically
certified sickness absence among both men and women. This association is independent of
prevalent mental disorders and physical illnesses.
3. Sleepiness and Days of Recovery
Transportation Research Part F 3 (2000) 251-256
Akerstedt, T et al.
In the literature recovery after work is taken for granted – one has 16 h off between work bouts
and one has 36 h off each weekend. However, the situation for those working irregular work
hours may be quite different because of night work, long shifts, or long sequences of working
days. Strictly speaking we don’t have any scientific support for theories on how recovery days
should be patterned. This paper, therefore, brings together data from a series of our own studies
that involve irregular work hours, with the specific purpose of looking at the recovery process.
The results show that for the average normal office week worker two days of recovery are
normally sufficient. For those who work long shifts in long sequences three days are needed for
normalization, whereas 12 h shifts in 2-3 day sequences seem not to cause accumulated fatigue.
Interestingly, fatigue/sleepiness is often at its peak during the first day of recovery – not the last
day of the working week. Air crew and oil rig workers take longer time to recover, probably
because of too much adjustment of the biological clock. As a rule, long haul air crew is usually
much more fatigued than short haul crew during their days off, despite the fact that long haul
flying is voluntary and opted for by those who fly it. Also, train drivers are affected during their
days off by their irregular work hours – in particular backward rotating schedules seem to cause
accumulation of fatigue. The results suggest that one day of recovery never is sufficient, two
days usually is, whereas 3-4 days are necessary after periods of severely disturbed circadian
rhythmicity.
7
4. Neurobehavioral performance of residents after heavy night call vs after alcohol
ingestion.
JAMA. 2005 Sep 7;294(9):1025-33.
Arnedt JT, Owens J, Crouch M, Stahl J, Carskadon MA.
Department of Psychiatry and Human Behavior, Brown Medical School, Providence, RI, USA.
tarnedt@med.umich.edu
Comment in
JAMA. 2006 Jan 11;295(2):162; author reply 162-3.
JAMA. 2005 Sep 7;294(9):1104-6.
CONTEXT: Concern exists about the effect of extended resident work hours; however, no study
has evaluated training-related performance impairments against an accepted standard of
functional impairment.
OBJECTIVES: To compare post-call performance during a heavy call rotation (every fourth or
fifth night) to performance with a blood alcohol concentration of 0.04 to 0.05 g% (per 100 mL of
blood) during a light call rotation, and to evaluate the association between self-assessed and
actual performance.
DESIGN, SETTING, AND PARTICIPANTS: A prospective 2-session within-subject study of
34 pediatric residents (18 women and 16 men; mean age, 28.7 years) in an academic medical
center conducted between October 2001 and August 2003, who were tested under 4 conditions:
light call, light call with alcohol, heavy call, and heavy call with placebo.
INTERVENTIONS: Residents attended a test session during the final week of a light call
rotation (non-post-call) and during the final week of a heavy call rotation (post-call). At each
session, they underwent a 60-minute test battery (light and heavy call conditions), ingested either
alcohol (light call with alcohol condition) or placebo (heavy call with placebo condition), and
repeated the test battery. Performance self-evaluations followed each test.
MAIN OUTCOME MEASURES: Sustained attention, vigilance, and simulated driving
performance measures; and self-report sleepiness, performance, and effort measures.
RESULTS: Participants achieved the target blood alcohol concentration. Compared with light
call, heavy call reaction times were 7% slower (242.5 vs 225.9 milliseconds, P<.001);
commission errors were 40% higher (38.2% vs 27.2%, P<.001); and lane variability (7.0 vs 5.5
ft, P<.001) and speed variability (4.1 vs 2.4 mph, P<.001) on the driving simulator were 27% and
71% greater, respectively. Speed variability was 29% greater in heavy call with placebo than
light call with alcohol (4.2 vs 3.2 mph, P = .01), and reaction time, lapses, omission errors, and
off-roads were not different. Correlation between self-assessed and actual performance under
heavy call was significant for commission errors (r = -0.45, P = .01), lane variability (r = -0.76,
P<.001), and speed variability (r = -0.71, P<.001), but not for reaction time.
CONCLUSIONS: Post-call performance impairment during a heavy call rotation is comparable
with impairment associated with a 0.04 to 0.05 g% blood alcohol concentration during a light
call rotation, as measured by sustained attention, vigilance, and simulated driving tasks.
Residents' ability to judge this impairment may be limited and task-specific.
8
5. Neurobehavioral, health, and safety consequences associated with shift work in safetysensitive professions.
Curr Neurol Neurosci Rep. 2009 Mar;9(2):155-64.
Barger LK, Lockley SW, Rajaratnam SM, Landrigan CP.
Division of Sleep Medicine, Brigham and Women's Hospital, 221 Longwood Avenue, Boston,
MA 02115, USA. lkbarger@hms.harvard.edu
Almost 15% of the full-time workers in the United States are shift workers. We review the
physiologic challenges inherent not only in traditional night or rotating shifts but also in
extended-duration shifts and other nonstandard hours. The challenging schedules of those in
particularly safety-sensitive professions such as police officers, firefighters, and health care
providers are highlighted. Recent findings describing the neurobehavioral, health, and safety
outcomes associated with shift work also are reviewed. Comprehensive fatigue management
programs that include education, screening for common sleep disorders, and appropriate
interventions need to be developed to minimize these negative consequences associated with
shift work.
6. Understanding the human factors contribution to railway accidents and incidents in
Australia.
Accid Anal Prev. 2008 Sep;40(5):1750-7. Epub 2008 Jul 9.
Baysari MT, McIntosh AS, Wilson JR.
University of New South Wales, NSW 2052, Australia. m.baysari@unsw.edu.au
Forty rail safety investigation reports were reviewed and a theoretical framework (the Human
Factors Analysis and Classification System; HFACS) adopted as a means of identifying errors
associated with rail accidents/incidents in Australia. Overall, HFACS proved useful in
categorising errors from existing investigation reports and in capturing the full range of relevant
rail human factors data. It was revealed that nearly half the incidents resulted from an equipment
failure, most of these the product of inadequate maintenance or monitoring programs. In the
remaining cases, slips of attention (i.e. skilled-based errors), associated with decreased alertness
and physical fatigue, were the most common unsafe acts leading to accidents and incidents.
Inadequate equipment design (e.g. driver safety systems) was frequently identified as an
organisational influence and possibly contributed to the relatively large number of
incidents/accidents resulting from attention failures. Nearly all incidents were associated with at
least one organisational influence, suggesting that improvements to resource management,
organisational climate and organisational processes are critical for Australian accident and
incident reduction. Future work will aim to modify HFACS to generate a rail-specific framework
for future error identification, accident analysis and accident investigation.
9
7. Division of Applied Research and Technology, National Institute for Occupational Safety
and Health, Cincinnati, OH 45226-1998, USA.
Ind Health. 2006 Oct;44(4):531-6.
Possible broad impacts of long work hours.
Caruso CC.
The paper summarizes research linking long work hours to a wide range of risks to workers,
families, employers, and the community. The risks are theorized to stem from less time to
recover from work, longer exposure to workplace hazards, and less time to attend to non-work
responsibilities. Risks to workers include sleep deprivation, poor recovery from work,
decrements in neuro-cognitive and physiological functioning, illnesses, adverse reproductive
outcomes, and injuries. Risks to families include delayed marriages and child bearing, and
obesity in children. Risks to employers include reduced productivity and increases in workers
errors. Mistakes by fatigued workers have broad reaching impacts to the community: medical
errors, automobile crashes with other drivers on the road, and industrial disasters that damage the
environment.
8. The effect of occupation and industry on the injury risks from demanding work
schedules.
J Occup Environ Med. 2008 Oct;50(10):1185-94.
Dembe AE, Delbos R, Erickson JB.
Division of Health Services Management and Policy, The Ohio State University College of
Public Health, Columbus, Ohio 43210, USA. adembe@cph.osu.edu
OBJECTIVE: Employees working in nonstandard shifts and long-hour schedules have an
increased risk for job-related injuries and illnesses. This study estimates the extent of that risk
among various occupations and industries.
METHODS: Longitudinal data for 13 years among a sample of nearly 11,000 employees aged 22
to 43 was used to calculate the risk of injury by occupation and industry for six types of
demanding work schedules. Cox proportional hazard regression analyses were used to estimate
risks within specific occupational and industrial classifications.
RESULTS: The greatest risks of job-related injury were among 1) construction workers in
evening shifts, 2) professional, technical, and managerial personnel working overtime schedules,
and 3) employees working overtime shifts in the business and repair services sectors.
CONCLUSIONS: Injury prevention efforts should be targeted toward employees in specific
industries and occupations who work certain long-hour and shift work schedules.
10
9. The impact of overtime and long work hours on occupational injuries and illnesses: new
evidence from the United States.
Occup Environ Med. 2005 Sep;62(9):588-97.
Dembe AE, Erickson JB, Delbos RG, Banks SM.
Center for Health Policy & Research, University of Massachusetts Medical School, Shrewsbury,
MA 01545, USA. Allard.Dembe@umassmed.edu
Comment in Occup Environ Med. 2005 Sep;62(9):585.
AIMS: To analyse the impact of overtime and extended working hours on the risk of
occupational injuries and illnesses among a nationally representative sample of working adults
from the United States.
METHODS: Responses from 10,793 Americans participating in the National Longitudinal
Survey of Youth (NLSY) were used to evaluate workers' job histories, work schedules, and
occurrence of occupational injury and illness between 1987 and 2000. A total of 110,236 job
records were analysed, encompassing 89,729 person-years of accumulated working time.
Aggregated incidence rates in each of five exposure categories were calculated for each NLSY
survey period. Multivariate analytical techniques were used to estimate the relative risk of long
working hours per day, extended hours per week, long commute times, and overtime schedules
on reporting a work related injury or illness, after adjusting for age, gender, occupation, industry,
and region.
RESULTS: After adjusting for those factors, working in jobs with overtime schedules was
associated with a 61% higher injury hazard rate compared to jobs without overtime. Working at
least 12 hours per day was associated with a 37% increased hazard rate and working at least 60
hours per week was associated with a 23% increased hazard rate. A strong dose-response effect
was observed, with the injury rate (per 100 accumulated worker-years in a particular schedule)
increasing in correspondence to the number of hours per day (or per week) in the workers'
customary schedule.
CONCLUSIONS: Results suggest that job schedules with long working hours are not more risky
merely because they are concentrated in inherently hazardous industries or occupations, or
because people working long hours spend more total time "at risk" for a work injury. Strategies
to prevent work injuries should consider changes in scheduling practices, job redesign, and
health protection programmes for people working in jobs involving overtime and extended
hours.
11
10. Long workhours, work scheduling and work-related injuries among construction
workers in the United States.
Scand J Work Environ Health. 2005 Oct;31(5):329-35.
Dong X.
The Center to Protect Workers' Rights, Silver Spring, MD 20910, USA. SDong@cpwr.com
OBJECTIVES: The objectives of this study were (i) to examine work scheduling in construction
and (ii) to establish whether there is any connection between workhours and safety outcomes
among construction workers.
METHODS: The National Longitudinal Survey of Youth, 1979 cohort (NLSY79), was used for
the data analysis. Odds ratios were used to measure the risk of work-related injury in different
worker groups.
RESULTS: The findings showed that (i) construction workers started work earlier, worked
longer days and fewer weeks a year, and were more likely to hold multiple jobs and change jobs
than their nonconstruction counterparts and (ii) long workhours and irregular work schedules
were significantly associated with a higher work-related injury rate after control for possible
confounders.
CONCLUSION: The results provide evidence that overtime and irregular work scheduling have
an adverse effect on worker safety.
11. Work hours, workload, sleep and fatigue in Australian Rail Industry employees.
Appl Ergon. 2011 Jan;42(2):202-9. Epub 2010 Aug 5.
Dorrian J, Baulk SD, Dawson D.
The Centre for Sleep Research, The University of South Australia, Adelaide, Australia.
jill.dorrian@unisa.edu.au
Research suggests that less than 5 h sleep in the 24 h prior to work and/or more than 16 h of
wakefulness can significantly increase the likelihood of fatigue-related impairment and error at
work. Studies have also shown exponential safety declines with time on shift, with roughly
double the likelihood of accident or injury after 10 h relative to the first 8h. While it is
acknowledged that reduced sleep, increased wakefulness and longer work hours produce work
related fatigue, few studies have examined the impact of workload on this relationship. Studies in
the rail industry have focused on drivers. This study investigated fatigue in a large sample of
Australian Rail Industry Employees. Participants were from four companies (n = 90: 85m, 5f;
mean age 40.2 ± 8.6 y). Data was analysed for a total of 713 shifts. Subjects wore wrist
actigraphs and completed sleep and work diaries for 14-days. They also completed the SamnPerelli Fatigue Scale at the beginning and end of shifts, and the NASA-TLX workload scale at
least twice during each shift. Average (±SD) sleep length (7.2 ± 2.6h), prior wake at shift end
(12.0 ± 4.7h), shift duration (8.0 ± 1.3) and fatigue (4.1 ± 1.3, "a little tired, less than fresh")
12
were within limits generally considered acceptable from a fatigue perspective. However,
participants received 5 h or less sleep in the prior 24 h on 13%, were awake for at least 16 h at
the end of 16% and worked at least 10 h on 7% of shifts. Subjects reported that they felt
"extremely tired, very difficult to concentrate," or "completely exhausted, unable to function
effectively" on 13% of shifts. Sleep length (OR = 0.88, p < 0.01), shift duration (OR = 1.18, p <
0.05), night shift (REF = morning shift, OR = 2.12, p < 0.05) and workload ratings (OR = 1.2, p
< 0.05) were significant predictors of ratings of extreme tiredness/exhaustion (yes/no). While on
average, sleep loss, extended wakefulness, longer work hours and work-related fatigue do not
appear problematic in this sample, there is still a notable percentage of shifts that are likely to be
associated with high levels of work-related fatigue. Given the size of the Australian Rail
Industry, with thousands of shifts occurring each day, this is potentially of operational concern.
Further, results indicate that, in addition to sleep length, wakefulness and work hours, workload
significantly influences fatigue. This has possible implications for bio-mathematical predictions
of fatigue and for fatigue management more generally.
12. The influence of sustained attention on railway accidents.
Accid Anal Prev. 1997 Jul;29(4):533-9.
Edkins GD, Pollock CM.
Bureau of Air Safety Investigation, Australia.
Train accidents and near accidents occurring over a 3-year period were examined within an
Australian public rail authority. Retrospective analysis of 112 incidents according to Reason's
(1992) Generic Error Modelling System (Reason, 1992, Human Error. Cambridge University
Press, Cambridge), revealed a propensity of skill based errors across the more common types of
rail mishaps. In agreement with previous rail research, sustained attention was the most salient
contributing human factor across all incident types, particularly inattentiveness to railway
signals. The unfavourable nature of the working environment and the repetitive nature of the
train driving task are discussed in light of reducing attentional deficits. In addition, a Railway
Safety Checklist was developed to identify train drivers perception of safety. One hundred and
ninety train drivers indicated that staff attitude in the form of low morale was a serious problem
in the safe conduct of their job. The results of this study imply that useful strategies for
improving driver vigilance should be directed at improving the safety culture of the operating
environment.
13
13. Detrimental effects of variable work shifts on quality of sleep, general health and work
performance.
Med Princ Pract. 2008;17(6):453-7. Epub 2008 Oct 3.
Fido A, Ghali A.
Department of Psychiatry, Faculty of Medicine, Kuwait University, Kuwait. fido@hsc.edu.kw
OBJECTIVES: The aim of this study was to explore the detrimental effects of working a varying
pattern of 8-hour shifts on quality of sleep, general health and work performance.
SUBJECTS AND METHODS: The Arabic version of the Pittsburgh Sleep Quality Index (PSQI)
and 2 self-administered questionnaires were used to assess quality of sleep, work performance
and general health in a sample of 200 males on a schedule of varying 8-hour shifts at the Kuwait
Oil Company. A matched sample of an equal number of workers on a fixed daytime shift as a
control group was enrolled in the study.
RESULTS: Compared with men working on a straight daytime shift schedule, those working on
8-hour variable shifts exhibited higher rates of heavy smoking (p < 0.003), coffee/tea
consumption (p < 0.0001), constipation (p < 0.002), job stress (p < 0.0001) and poor sexual
performance (p < 0.0001). Variable-shift workers reported persistent sleep disturbances in 3
dimensions of the global score of the PSQI (p < 0.0001). They also had significantly more
complaints of fatigue (p < 0.005), poor level of work performance (p < 0.005) and loss of
concentration (p < 0.005). Shift workers were significantly more prone to making errors and
having accidents at work, and were more likely to report absence from work than the controls (p
< 0.0001 and p < 0.005, respectively).
CONCLUSION: These results suggest that the majority of workers on an 8-hour variable-shift
schedule experienced various health problems, poor quality of sleep and an increased risk for
errors and accidents at work as compared with those workers on a straight daytime shift
schedule. There is a need to compare potential benefits of an alternative work shift schedule.
14. Work patterns and fatigue-related risk among junior doctors.
Occup Environ Med. 2007 Nov;64(11):733-8. Epub 2007 Mar 26.
Gander P, Purnell H, Garden A, Woodward A.
Sleep/Wake Research Centre, Massey University, Wellington, New Zealand.
p.h.gander@massey.ac.nz
Comment in
Occup Environ Med. 2007 Nov;64(11):719-20.
BACKGROUND: To reduce fatigue-related risk among junior doctors, recent initiatives in
Europe and the USA have introduced limits on work hours. However, research in other
industries has highlighted that other aspects of work patterns are important in generating fatigue,
14
in addition to total work hours. The Australian Medical Association (AMA) has proposed a more
comprehensive fatigue risk management approach.
OBJECTIVES: To evaluate the work patterns of New Zealand junior doctors based on the AMA
approach, examining relationships between different aspects of work and fatigue-related
outcomes.
METHODS: An anonymous questionnaire mailed to all house officers and registrars dealt with
demographics, work patterns, sleepiness, fatigue-related clinical errors, and support for coping
with work demands. Each participant was assigned a total fatigue risk score combining 10
aspects of work patterns and sleep in the preceding week.
RESULTS: The response rate was 63% (1366 questionnaires from doctors working > or =40
hours a week). On fatigue measures, 30% of participants scored as excessively sleepy (Epworth
Sleepiness Score >10), 24% reported falling asleep driving home since becoming a doctor, 66%
had felt close to falling asleep at the wheel in the past 12 months, and 42% recalled a fatiguerelated clinical error in the past 6 months. Night work and schedule instability were
independently associated with more fatigue measures than was total hours worked, after
controlling for demographic factors, The total risk score was a significant independent risk factor
for all fatigue measures, in a dose-dependent manner (all p<0.01). Regular access to adequate
supervision at work reduced the risk of fatigue on all measures.
CONCLUSIONS: To reduce fatigue-related risk among junior doctors, account must be taken of
factors in addition to total hours of work and duration of rest breaks. The AMA fatigue risk
assessment model offers a useful example of a more comprehensive approach.
15. Accident risk as a function of hour at work and time of day as determined from
accident data and exposure models for the German working population.
Scand J Work Environ Health. 1998;24 Suppl 3:43-8.
Hänecke K, Tiedemann S, Nachreiner F, Grzech-Sukalo H.
AWiS Working-Time and Organizational Consulting and Research, Hude, Federal Republic of
Germany.
OBJECTIVES: Recent studies indicate that accident risk may be a function of hour at work and
time of day. Further evidence was sought for these assumptions, along with the answer to the
question of whether the risk of accident can be conceived as an interaction between hours at
work and time of day.
METHODS: Data on more than 1.2 million accidents for the year 1994 were provided, all listed
according to the time of day and hour at work. Since information about how long each day and at
what time of day people work is not available in Germany, different exposure models had to be
estimated. For estimating the risk of having an accident relative accident risks were calculated
from the ratio of accident frequencies to the exposure data.
RESULTS: An exponentially increasing accident risk was observed beyond the 9th hour at work.
The relative accident risks differed considerably according to the respective exposure model with
regard to time of day. A highly significant interaction effect was found for hour at work by time
of day, the percentage of accidents at different hours at work varying according to the particular
15
time of day when work is started. For the 3 "traditional" shiftwork starting times, it was shown
that, with later starting times, the relative accident risk increased dramatically beyond the 8th
hour at work.
CONCLUSIONS: Since the results clearly indicate that there are time-related effects on
occupational accident risk, more detailed analyses are called for. More elaborated exposure
models should be used to assess the efficiency of work schedules with extended workhours,
especially under shiftwork conditions. The results also indicate the necessity of recording and
providing adequate databases for such analyses.
16. The effect of an irregular shift system on sleepiness at work in train drivers and railway
traffic controllers.
J Sleep Res. 2002 Jun;11(2):141-51.
Härmä M, Sallinen M, Ranta R, Mutanen P, Müller K.
Brain Work Laboratories, Finnish Institute of Occupational Health, Helsinki, Finland.
mikko.harma@ttl.fi
Sleepiness and fatigue are frequent problems in railway transportation with occasional monotony
and irregular shift schedules. This study aimed at (1) studying the prevalence of severe
sleepiness in shifts and (2) examining which shift and sleep-related factors were associated with
the occurrence of severe sleepiness in an irregular shift system. A total of 126 randomly selected
male train drivers (Tdrs) and 104 railway traffic controllers (Tcos) were investigated using
questionnaires and sleep-wake diaries. A sleep diary was used to collect information on
sleepiness at work and sleeping times during the 21 consecutive days of the study. The
prevalence of severe sleepiness at work (i.e. Karolinska Sleepiness Scale 7 or higher) was
modelled by a logistic regression analysis for repeated measurements (GEE) using different shift
schedule related factors and sleep length as explanatory variables. Severe sleepiness was
reported in 49% (Tdrs) and 50% (Tcos) of the night shifts and in 20% (Tdrs) and 15% (Tcos) of
the morning shifts. The odds ratios showed that the risk for severe sleepiness was 6-14 times
higher in the night shift and about twice as high in the morning shift compared with the day shift.
Age affected the two occupational samples differently: with Tdrs increased age was associated
with an additional 8% reduction of risk for severe sleepiness for each year of age, while the Tcos
did not show any age dependency. Shift length increased the risk by 15% for each hour of the
shift and main sleep period decreased the risk by 15% for each hour of the main sleep. The risk
of severe sleepiness was not consistently related to the time-off period before the shifts. The
results indicate that adjustments for shift timing, length and off-duty time, in addition to actions
aiming at extending the main sleep period, would probably decrease severe sleepiness in railway
transportation.
16
17. Towards the 24-hour society--new approaches for aging shift workers?
Scand J Work Environ Health. 1999 Dec;25(6):610-5.
Härmä MI, Ilmarinen JE.
Finnish Institute of Occupational Health, Department of Physiology, Helsinki.
mikko.harma@occuphealth.fi
The new "24-hour society" increases night work and the diversity of flexible work-hour patterns.
At the same time, the number of older shift workers is growing in most developed countries due
to the general aging of the working population. Together with new experimental and
epidemiologic data on the alarming relationship of shift work to fatigue, performance, accidents,
and chronic health effects like coronary heart disease, there is reason to believe that shift work
may become a major occupational health and safety problem in the near future. The prevention
of shiftwork-related health and safety problems will be a major challenge for the employer,
employees, and occupational health professionals during the next few decades. The present paper
shortly summarizes the current knowledge on the relationship between shift work, aging, and
health and outlines practical countermeasures and research needs to improve the health and
well-being of aging shift workers.
18. The effect of shiftwork related fatigue on the family life of train operators: implications
for safety and health professionals.
Work. 2006;26(2):115-21.
Holland DW.
Occupational Health Psychology, Union Pacific Railroad Company, 1400 Douglas Street, STOP
1040, Omaha, NE 68179, USA. d.holland1@cox.net
Drawing upon an original research study about the effects of fatigue on train operators, the
present article focuses upon family issues as having the most significant impact on the
participants. Family support, for example, represents an important mechanism for managing and
coping with fatigue. Family support comprises understanding of the physiological and emotional
issues surrounding shiftwork and erratic work schedules. This article explores the impact of
fatigue upon a variety of family and relational issues. This inquiry describes the impact of family
on the broader employee view of managing fatigue that considers such comprehensive issues as
perception of the work environment, emotional stability, personal control concerns and other
positive attributes. These issues ultimately impact the health, productivity and performance of
employees. Final discussion includes implications for workplace application of the research
findings.
17
19. Health and psychosocial effects of flexible working hours.
Rev Saúde Pública. 2004 Dec;38 Suppl:11-8. Epub 2004 Dec 13.
Janssen D, Nachreiner F.
Department of Psychology, Carl von Ossietzky Universitaet Oldenburg, Oldenburg, Germany.
daniela.janssen@uni-oldenburg.de
OBJECTIVE: To examine whether any impairments in health and social lives can be found
under different kinds of flexible working hours, and whether such effects are related to specific
characteristics of these working hours.
METHODS: Two studies -- a company based survey (N=660) and an internet survey (N=528) -have been conducted. The first one was a questionnaire study (paper and pencil) on employees
working under some 'typical' kinds of different flexible working time arrangements in different
companies and different occupational fields (health care, manufacturing, retail, administration,
call centres). The second study was an internet-based survey, using an adaptation of the
questionnaire from the first study.
RESULTS: The results of both studies consistently show that high variability of working hours is
associated with increased impairments in health and well-being and this is especially true if this
variability is company controlled. These effects are less pronounced if variability is selfcontrolled; however, autonomy does not compensate the effects of variability.
CONCLUSIONS: Recommendations for an appropriate design of flexible working hours should
be developed in order to minimize any impairing effects on health and psychosocial well-being;
these recommendations should include -- besides allowing for discretion in controlling one's
(flexible) working hours -- that variability in flexible working hours should be kept low (or at
least moderate), even if this variability is self-controlled.
20. The impact of extended leave on sleep and alertness in the Australian rail industry.
Ind Health. 2005 Jan;43(1):105-13.
Kandelaars KJ, Lamond N, Roach GD, Dawson D.
Centre for Sleep Research, Level 5, Basil Hetzel Institute, The Queen Elizabeth Hospital,
Woodville, SA 5011, Australia.
In the past, scientific studies have investigated the effects of shift timing and duration on sleep
and alertness in the rail industry. To our knowledge no research has been conducted to determine
the effects of extended break lengths (>48 h) on these factors. Hence, this study analyses the
work and rest schedules of 304 Australian rail employees (mean age 41.3 yr, standard deviation
7.4 yr) to determine the effect of prior break lengths (12-169 h) on sleep and subjective alertness
at work after periods of leave. Extended break periods (>48 h) were found to increase the length
of the sleep prior to returning to work and reduce the total wake time to the end of the first shift,
but did not influence levels of subjective alertness immediately prior to the commencement of
18
the first shift. Research into the influence of longer break periods (>169 h) is needed in order to
make definitive conclusions regarding sensible return to work policies after extended leave
within the Australian rail industry.
21. Overtime, psychosocial working conditions, and occurrence of non-insulin dependent
diabetes mellitus in Japanese men.
J Epidemiol Community Health. 1999 Jun;53(6):359-63.
Kawakami N, Araki S, Takatsuka N, Shimizu H, Ishibashi H.
Department of Public Health, Faculty of Medicine, University of Tokyo, Japan.
OBJECTIVES: To ascertain the effects of overtime and psychosocial job conditions on the
occurrence of non-insulin dependent diabetes mellitus (NIDDM) in Japan.
DESIGN: An eight year prospective cohort study.
SETTING: An electrical company in Japan.
PARTICIPANTS: In 1984, a mailed questionnaire was sent to industrial workers of an electrical
company in Japan. After excluding those who had a history of diabetes mellitus or other chronic
diseases, 2597 male respondents were prospectively followed up for the succeeding eight years.
Data from 2194 (84%) who were completely followed up were analysed. The occurrence of
NIDDM during the follow up period was assessed according to the WHO criteria on the basis of
an annual screening programme.
MAIN RESULTS: The age adjusted incidence of NIDDM was significantly higher in those who
worked overtime more than 50 hours per month than in those who worked 25 hours or less per
month (p < 0.05). It was significantly higher in those who worked with new technology at
baseline than in those who did not (p < 0.05). Cox's proportional hazard model indicated that
those who worked overtime more than 50 hours per month had 3.7 times higher risk of NIDDM
after controlling for known risk factors (p < 0.01) and those who worked with new technology
had 2.4 times higher risk of NIDDM (p < 0.05).
CONCLUSIONS: It is suggested that longer overtime and use of new technology are risk factors
of NIDDM in Japanese men.
19
22. Working overtime is associated with anxiety and depression: the Hordaland Health
Study.
J Occup Environ Med. 2008 Jun;50(6):658-66.
Kleppa E, Sanne B, Tell GS.
Medical Faculty, University of Bergen, Bergen, Norway. elisabeth.kleppa@student.uib.no
OBJECTIVE: To examine whether long work hours are associated with increased levels and
prevalences of anxiety and depression.
METHODS: Overtime workers (n = 1350) were compared with a reference group of 9092
workers not working overtime regarding anxiety and depression by means of the Hospital
Anxiety and Depression Scale. Self-reported information on various work-related factors,
demographics, lifestyle, and somatic health was included.
RESULTS: Overtime workers of both genders had significantly higher anxiety and depression
levels and higher prevalences of anxiety and depressive disorders compared with those working
normal hours. Findings suggest a dose-response relationship between work hours and anxiety or
depression.
CONCLUSIONS: Working overtime is associated with increased levels of anxiety and
depression. The working groups differed significantly regarding several factors including income
and heavy manual labor.
23. Incidence of near accidental drowsing in locomotive driving during a period of rotation.
J Hum Ergol (Tokyo). 1975 Sep;4(1):65-76.
Kogi K, Ohta T.
The incidence of drowsings as a cause of near traffic accidents was studied on the basis of daily
recordings or near accidental events by 288 locomotive drivers during a rotation period of 2-3
weeks. Of 198 near accidents reported during 2,290 trips, 34 cases, or 1,5 cases per 100 trips,
were operation misses involving drowsing or strong drowsiness. Improper operation due to
drowsing occurred at a certain rate for any group of drivers, irrespective of the type of train,
running sections, weather, and other operative conditions such as train delays, whereas 117 cases
of danger caused by unforeseen obstacles on the track were related to site characteristics, and 47
cases of other disorders were frequent in unusual operative conditions such as arrival-departure,
poor signal display, wrong instructions, or equipment failure. Thus continued driving under
ordinary track conditions at a more or less constant speed was likely to induce drowsiness under
the dominant influences of fatigue and time of the day; 79% of such cases occurred between
midnight and 6 a.m. Most drowsings on the second night appeared during the first 2-4 hr of duty.
Effects of monotony and insufficient rest were discussed in relation to recurrent fluctuation in
vigilance.
20
24. Organisational factors and scheduling in locomotive engineers and conductors: Effects
on fatigue, health and social well-being.
Appl Ergon. 2010 Jan;41(1):62-71. Epub 2009 May 17.
Ku CH, Smith MJ.
Department of Industrial Management, National Taiwan University of Science and Technology,
43 Keelung Road, Section 4, Taipei 10607, Taiwan. chiahuaku@mail.ntust.edu.tw
This study examines critical organisational factors and work scheduling in railway freight
operators to understand how job-related factors are related to fatigue, health and social wellbeing. A 148-item questionnaire was developed and distributed to a sample of 276 locomotive
engineers and conductors working for the U.S. Operations of a North American Railway. One
hundred and twenty-five questionnaires were returned, which was a response rate of 45.3%.
Structural equation modeling was performed to identify the relationships between the examined
factors. The analytical results of this study indicate that organisational factors and the scheduling
system could not be distinguished as two separate factors. The scheduling system is not just the
practice of assigning locomotive crewmen to trains, but it is a function tightly connected with
other organisational factors. Social Well-Being is an important mediator between Scheduling and
Fatigue. Finally, the study revealed a strong relationship between fatigue and health complaints.
25. Train drivers' sleep and alertness during short relay operations.
Appl Ergon. 2005 May;36(3):313-8.
Lamond N, Darwent D, Dawson D.
The Centre for Sleep Research, The University of South Australia, Adelaide, SA, Australia.
nicole.lamond@unisa.edu.au
Within Australia, there has been a recent expansion of relay working operations. To address
concerns about the amount of sleep obtained by drivers in relay vans, and potential deficits in
alertness associated with relay work, the current study assessed the sleep behaviour and alertness
of 15 train drivers working short (<48 h) relay operations. In total, drivers obtained 8-12h of
sleep during the relay trip (which took approx 40 h). Overall, they reported that they felt more
alert following each sleep period. Drivers were able to sustain attention during the 10-min
vigilance tasks administered before and after each shift. These findings suggest that the amount
of sleep obtained in crew vans during short relay operations is sufficient to maintain alertness
during the trip. They also emphasise the importance of scheduling shifts to maximise the number
of sleep opportunities that occur between 2200 and 0700 h.
21
26. Overtime work, insufficient sleep, and risk of non-fatal acute myocardial infarction in
Japanese men.
Occup Environ Med. 2002 Jul;59(7):447-51.
Liu Y, Tanaka H; Fukuoka Heart Study Group.
Graduate student of Department of Preventive Medicine, Graduate School of Medical Sciences,
Kyushu University, Fukuoka 812-8582, Japan. yliu@gan2.res.ncc.go.jp
OBJECTIVES: To examine the relation between working hours and hours of sleep and the risk
of acute myocardial infarction (AMI), with special reference to the joint effect of these two
factors.
METHOD: Case-control study in Japan. Cases were 260 men aged 40-79 admitted to hospitals
with AMI during 1996-8. Controls were 445 men free from AMI matched for age and residence
who were recruited from the resident registers. Odds ratios of AMI relative to mean weekly
working hours and daily hours of sleep in the past year or in the recent past were calculated.
RESULTS: Weekly working hours were related to progressively increased odds ratios of AMI in
the past year as well as in the past month, with a twofold increased risk for overtime work
(weekly working hours >or=61) compared with working hours <or=40. Short time sleep (daily
hours of sleep <or=5) and frequent lack of sleep (2 or more days/week with <5 hours of sleep)
were also associated with a two to threefold increased risk. Frequent lack of sleep and few days
off in the recent past showed greater odds ratios than those in the past year.
CONCLUSIONS: Overtime work and insufficient sleep may be related to increased risk of AMI.
27. Burnout and risk of type 2 diabetes: a prospective study of apparently healthy
employed persons.
Psychosom Med. 2006 Nov-Dec;68(6):863-9.
Melamed S, Shirom A, Toker S, Shapira I.
Department of Epidemiology and Preventive Medicine, Sackler Faculty of Medicine, Tel Aviv
University, Ramat Aviv, Tel Aviv, Israel. smelamed@post.tau.ac.il
OBJECTIVE: This prospective study was designed to test the extent to which the onset of type 2
diabetes in apparently healthy individuals was predicted by burnout, a unique affective response
to combined exposure to chronic stressors.
METHODS: The study participants were 677 employed men and women who were followed up
for 3 to 5 years (mean = 3.6 years) for the onset of diagnosed type 2 diabetes. Burnout was
assessed by the Shirom-Melamed Burnout Measure with its three subscales: emotional
exhaustion, physical fatigue, and cognitive weariness.
RESULTS: The burnout symptoms were remarkably consistent over the follow-up period
irrespective of changes in place of work and in employment status. During the follow-up period,
17 workers developed type 2 diabetes. Logistic regression results indicated that burnout was
22
associated with a 1.84-fold increased risk of diabetes (95% confidence interval [CI] = 1.19-2.85)
even after adjusting for age, sex, body mass index, smoking, alcohol use, leisure time physical
activity, initial job category, and follow-up duration. In a subsample of 507 workers, the relative
risk of diabetes was found to be much higher after additional control for blood pressure levels
(odds ratio = 4.32, 95% CI = 1.75-10.67), available only for this subsample.
CONCLUSIONS: These findings suggest that chronic burnout might be a risk factor for the
onset of type 2 diabetes in apparently healthy individuals.
28. Hours of work and the risk of developing impaired fasting glucose or type 2 diabetes
mellitus in Japanese male office workers.
Occup Environ Med. 2001 Sep;58(9):569-74.
Nakanishi N, Nishina K, Yoshida H, Matsuo Y, Nagano K, Nakamura K, Suzuki K, Tatara K.
Department of Social and Environmental Medicine, Course of Social Medicine, Osaka
University Graduate School of Medicine F2, 2-2 Yamada-oka, Suita-shi, Osaka 565-0871, Japan.
noriyuki@pbhel.med.osaka-u.ac.jp
OBJECTIVE: To investigate the association between duration of overtime and the development
of impaired fasting glucose (IFG) or type 2 diabetes mellitus (DM).
METHODS: A cohort of 1266 Japanese male office workers aged 35-59 years and free of IFG
(fasting plasma glucose concentration 6.1-6.9 mmol/l), type 2 DM (fasting plasma glucose
concentration of 7.0 mmol/l or more or taking hypoglycaemic medication), history of diabetes, or
medication for hypertension were re-examined over 5 successive years after their initial
examinations in 1994.
RESULTS: 138 men developed IFG or type 2 DM during the 5736 person-years of follow up.
After controlling for potential predictors of diabetes, the relative risks of IFG or type 2 DM,
compared with those who worked <8.0 hours a day, were 0.82 (95% confidence interval (95%
CI) 0.54 to 1.26), 0.69 (95% CI 0.38 to 1.26), 0.63 (95% CI: 0.37 to 1.09), and 0.50 (95% CI:
0.25 to 0.98) for those who worked 8.0-8.9, 9.0-9.9, 10.0-10.9, and of 11.0 hours or more a day,
respectively (p for trend=0.020). 87 and 54 men developed IFG and type 2 DM during the 5817
and 5937 person-years of follow up, respectively. The multivariate adjusted relative risks of IFG
tended to decrease with an increase in hours of overtime work a day, but did not reach
significance (p for trend=0.202). On the other hand, the multivariate adjusted relative risks of
type 2 DM significantly decreased with an increase in hours of overtime work a day (p for
trend=0.014).
CONCLUSION: Longer overtime is a negative risk factor for the development of IFG or type 2
DM in Japanese male office workers.
23
29. Long working hours and risk for hypertension in Japanese male white collar workers.
J Epidemiol Community Health. 2001 May;55(5):316-22.
Nakanishi N, Yoshida H, Nagano K, Kawashimo H, Nakamura K, Tatara K.
Department of Social and Environmental Medicine, Course of Social Medicine, Osaka
University Graduate School of Medicine F2, 2-2 Yamada-oka, Suita-shi, Osaka 565-0871, Japan.
noriyuki@pbhel.med.osaka-u.ac.jp
STUDY OBJECTIVE: To evaluate the association of long working hours with the risk for
hypertension.
DESIGN: A five year prospective cohort study.
SETTING: Work site in Osaka, Japan.
PARTICIPANTS: 941 hypertension free Japanese male white collar workers aged 35-54 years
were prospectively examined by serial annual health examinations. Men in whom borderline
hypertension and hypertension were found during repeated surveys were defined as incidental
cases of borderline hypertension and hypertension.
MAIN RESULTS: 336 and 88 men developed hypertension above the borderline level and
definite hypertension during the 3940 and 4531 person years, respectively. After controlling for
potential predictors of hypertension, the relative risk for hypertension above the borderline level,
compared with those who worked < 8.0 hours per day, was 0.63 (95% confidence intervals (CI):
0.43, 0.91) for those who worked 10.0-10.9 hours per day and 0.48 (95% CI: 0.31, 0.74) for
those who worked > or = 11.0 hours per day. The relative risk for definite hypertension,
compared with those who worked < 8.0 hours per day, was 0.33 (95% CI: 0.11, 0.95) for those
who worked > or = 11.0 hours per day. The multivariate adjusted slopes of diastolic blood
pressure (DBP) and mean arterial blood pressure (MABP) during five years of follow up
decreased as working hours per day increased. From the multiple regression analyses, working
hours per day remained as an independent negative factor for the slopes of systolic blood
pressure, DBP, and MABP.
CONCLUSIONS: These results indicate that long working hours are negatively associated with
the risk for hypertension in Japanese male white collar workers.
30. Beyond working time: Factors affecting sleep behaviour in rail safety workers
Accident Analysis & Prevention (2011) Article in progress
Jessica L. Paterson, Jill Dorrian, Larissa Clarkson, David Darwent, Sally A. Ferguson
Centre for Sleep research, University of South Australia
Abstract: There are many factors that may affect the sleep behaviour and subsequent fatigue risk
of shift workers. In the Australian rail industry the emphasis is primarily on the impact of
working time on sleep. The extent to which factors other than working time might affect the
sleep behaviour of employees in the large and diverse Australian rail industry is largely
24
unknown. The present study used sleep, work and fatigue diaries completed for two weeks, in
conjunction with actigraphy, to understand the contribution of demographic and health factors to
sleep behaviour in 40 rail safety workers. Both shift type and having dependents were significant
predictors of sleep duration (P&#xa0;&lt;&#xa0;.05). Sleep duration was greatest prior to night
shifts, followed by afternoon shifts and morning shifts. Participants with dependents got
significantly less sleep than participants without dependents. Both timing of sleep and smoking
were significant predictors of sleep quality (P&#xa0;&lt;&#xa0;.05). Day sleeps were associated
with lower subjective sleep quality than night sleeps and smokers reported poorer sleep quality
than non-smokers. These findings indicate that factors other than working time have the potential
to influence both the sleep duration and subjective sleep quality of rail safety workers.
31. Work/rest cycles in railroad operations: effects of shorter than 24-h shift work
schedules and on-call schedules on sleep.
Ergonomics. 2000 May;43(5):573-88.
Pilcher JJ, Coplen MK.
Department of Psychology, Bradley University, Peoria, IL 61625, USA. pilcher@bradley.edu
The current study examined the frequency with which shorter than 24-h work/rest cycles occur in
locomotive engineer work schedules, and what effects these work/rest cycles had on sleep
quantity and sleep quality. The results indicated that shorter than 24-h work/rest cycles occurred
in 33.6% of the work days reported by 198 locomotive engineers. In addition, the shorter than
24-h work/rest cycles occurred more frequently in work schedules that created an on-call work
system, such as road pool turn and extra board assignments, than in work schedules that used
more predictable or regular work times, such as regular road assignments and yard/local work.
As would be expected, when engineers worked shorter than 24-h work/rest cycles, they reported
less sleep and poorer sleep than under the longer than 24-h work/rest cycles. Similarly, on-call
work assignments resulted in less sleep and poorer sleep than regular work assignments. These
results indicate that specific aspects of the work schedules used in railroad operations,
particularly on-call operations that result in shorter than 24-h work/rest cycles, can lead to
increased sleep-related problems. Although the North American railroad industry is making
significant changes in on-call operations to minimize sleep-related problems from on-call
schedules, better fatigue-related models validated within the railroad industry are needed.
25
32. Self-report naps in irregular work schedules.
Ind Health. 2005 Jan;43(1):123-8.
Pilcher JJ, Popkin SM, Adkins K, Roether L.
Department of Psychology, Clemson University, 418 Brackett Hall, Clemson University,
Clemson, SC 29634-1355, USA.
Few studies have examined napping in irregular work schedules such as those experienced by
freight locomotive engineers. The current study examined the effect of napping in irregular work
schedules on sleep length and three subjective measures: ability to go to sleep, ability to stay
asleep, and a feeling of being well-rested upon awakening. One hundred and seventy-nine freight
engineers completed a 14-d activity log, providing information on sleep times and subjective
evaluations of sleep. The results indicated that days with naps resulted in significantly more total
sleep but less sleep in the main sleep period of the day. The days with naps also resulted in
somewhat more difficulty with going to sleep, staying asleep and with feeling well-rested upon
awakening. It is important to note, however, that when examining the days with naps, nap length
was not significantly correlated with main sleep time, ability to go to sleep, ability to stay asleep,
or feeling well-rested upon awakening. These results suggest that napping may be useful when
working irregular work schedules if the engineer is willing to accept a slight decrease in ability
to go to sleep, stay asleep, and feeling rested.
33. Comparing the effects of fatigue and alcohol consumption on locomotive engineers'
performance in a rail simulator.
J Hum Ergol (Tokyo). 2001 Dec;30(1-2):125-30.
Roach GD, Dorrian J, Fletcher A, Dawson D.
Centre for Sleep Research, University of South Australia, Adelaide, Australia.
Laboratory studies have established that the performance impairments due to fatigue and alcohol
consumption are quantitatively similar. However, the generalisability of this phenomenon is not
clear because comparisons have not been made in realistic work settings with experienced
shiftworkers. The aim of the current study was to quantify the effects of fatigue on performance
in a simulated work environment (i.e. rail simulator) and compare them with the effects of
alcohol consumption. It was hypothesised that fatigue would significantly impair driving
performance, and that this impairment would be quantitatively similar to that associated with
moderate levels of alcohol consumption. Twenty locomotive engineers participated in the study
with a randomised cross-over design and three conditions: baseline, fatigue, and alcohol. During
each 8-hour condition, participants completed four driving sessions in the rail simulator. The
results indicate that fatigue caused participants to disengage from operating the simulator such
that safety was traded off, not necessarily deliberately, against efficiency. The impairment in
safety due to fatigue was in a range similar to the impairment associated with moderate levels of
alcohol consumption. In summary, the study demonstrated that the effects of fatigue in a
simulated work environment can be quantified and may be considerable.
26
34. The amount of sleep obtained by locomotive engineers: effects of break duration and
time of break onset.
Occup Environ Med. 2003 Dec;60(12):e17.
Roach GD, Reid KJ, Dawson D.
Centre for Sleep Research, The University of South Australia, Woodville, South Australia,
Australia. greg.roach@unisa.edu.au
AIMS: To determine the effects of break duration and time of break onset on the amount of sleep
that locomotive engineers obtain between consecutive work periods.
METHODS: A total of 253 locomotive engineers (249 male, 4 female, mean age 39.7 years)
participated. Data were collected at 14 rail depots, where participants drove electric or diesel
locomotives; worked with another engineer or drove alone; carried passengers, freight, or coal;
and operated in rural or urban areas. Participants completed sleep diaries and work diaries for a
two week period while working their normal roster patterns.
RESULTS: For breaks that began at similar times of day, total sleep time (TST) increased with
break duration. For breaks of similar duration, TST was greater for those that occurred during the
night-time than for those that occurred during the daytime. An average of 3.1-7.9 hours sleep
was obtained in 12 hour breaks (minimum break requirement in the Australian rail industry),
depending on when the break began.
CONCLUSIONS: The duration and timing of breaks are both important factors in determining
the amount of sleep that locomotive engineers obtain between consecutive work periods.
Consequently, minimum length break requirements that do not include a time of day component
may not provide locomotive engineers with the opportunity to obtain a sufficient amount of sleep
prior to resuming work.
35. Sleepiness in various shift combinations of irregular shift systems.
Ind Health. 2005 Jan;43(1):114-22.
Sallinen M, Härmä M, Mutanen P, Ranta R, Virkkala J, Müller K.
Brain Research Unit, Finnish Institute of Occupational Health, Topeliuksenkatu 41a A, 00250
Helsinki, Finland.
The present study examined the occurrence of sleepiness in various shift combinations ending
with a night or morning shift. Three weeks' sleep/work shift diary data, collected from 126
randomly selected train drivers and 104 traffic controllers, were used in statistical analyses. The
occurrence of sleepiness at work (i.e., Karolinska Sleepiness Scale 7 or higher) was tested with a
generalised linear model with repeated measurements including explanatory factors related to
shifts, sleep, and individual characteristics. The prevalence of severe sleepiness varied between
25% and 62% in the combinations ending with a night shift and between 12% and 27% in the
combinations ending with a morning shift. The occurrence of sleepiness did not, however,
27
systematically vary between the shift combinations in either case. An increased risk for
sleepiness was associated with high sleep need and long shift duration in the night shift and with
high sleep need, short main sleep period, long shift duration and an early shift starting time in the
morning shift. Also having a child was associated with an increased risk for sleepiness in the
night shift. The results suggest that the shift history of 24-36 h prior to the night and the morning
shift is not strongly associated with the occurrence of sleepiness at work, but there are other
factors, such as shift length and starting time and sleep need, that affect a risk for sleepiness at
work.
36. Sleep-wake rhythm in an irregular shift system.
J Sleep Res. 2003 Jun;12(2):103-12.
Sallinen M, Härmä M, Mutanen P, Ranta R, Virkkala J, Müller K.
Brain and Work Research Units, and Department of Epidemiology and Biostatistics, Finnish
Institute of Occupational Health, Helsinki, Finland. mikael.sallinen@occuphealth.fi
Sleep in shift work has been studied extensively in regular shift systems but to a lesser degree in
irregular shifts. Our main aim was to examine the sleep-wake rhythm in shift combinations
ending with the night or the morning shift in two irregular shift systems. Three weeks'
sleep/work shift diary data, collected from 126 randomly selected train drivers and 104 traffic
controllers, were used in statistical analyses including a linear mixed model and a generalized
linear model for repeated measurements. The results showed that the sleep-wake rhythm was
significantly affected by the shift combinations. The main sleep period before the first night shift
shortened by about 2 h when the morning shift immediately preceded the night shift as compared
with the combination containing at least 36 h of free time before the night shift (reference
combination). The main sleep period before the night shift was most curtailed between two night
shifts, on average by 2.9 and 3.5 h among the drivers and the controllers, respectively, as
compared with the reference combination. Afternoon napping increased when the morning or the
day shift immediately preceded the night shift, the odds being 4.35-4.84 in comparison with the
reference combination. The main sleep period before the morning shift became 0.5 h shorter
when the evening shift preceded the morning shift in comparison with the sleep period after a
free day. The risk for dozing off during the shift was associated only with the shift length,
increasing by 17 and 35% for each working hour in the morning and the night shift, respectively.
The results demonstrate advantageous and disadvantageous shift combinations in relation to
sleep and make it possible to improve the ergonomy of irregular shift systems.
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37. Shift work and health.
Prim Care. 2000 Dec;27(4):1057-79.
Scott AJ.
Department of Environmental and Occupational Health, University of Pittsburgh Graduate
School of Public Health, Pittsburgh, USA.
Night work and rotating shift work disrupt the circadian timing system. This disruption may
produce significant deleterious symptoms in some workers. Certain medical conditions may be
aggravated by shift-work scheduling, and shift workers are at increased risk of experiencing
cardiovascular, gastrointestinal, and reproductive dysfunction. Vulnerable individuals may
develop clinical depression when working shifts. Primary care practitioners may intervene by
providing medical surveillance and educational programs for shift-working patients and their
families.
38. The Hinton train disaster.
Accid Anal Prev. 1990 Oct;22(5):443-55.
Smiley AM.
Human Factors North Inc., Toronto, Canada.
In February of 1986 a head-on collision occurred between a freight train and a passenger train in
western Canada killing 23 people and causing over $30 million of damage. A Commission of
Inquiry appointed by the Canadian government concluded that human error was the major reason
for the collision. This report discusses the factors contributing to the human error: mainly poor
work-rest schedules, the monotonous nature of the train driving task, insufficient information
about train movements, and the inadequate backup systems in case of human error.
39. Fatigue and alertness in the United States railroad industry part I: the nature of the
problem
Transportation Research Part F: Traffic Psychology and Behaviour, Volume 3, Issue 4,
December 2000, Pages 211-220, ISSN 1369-8478, 10.1016/S1369-8478(01)00005-5.
Donald Sussman, Michael Coplen
US Department of Transportation
Abstract: The railroad industry must actively manage employee fatigue and alertness problems to
maintain an optimal level of operational safety and productivity. Given the necessity to operate
29
nights and irregular hours, weekends and holidays under a wide range of physical conditions and
service demands, we must explore every reasonable avenue to ensure employees are fit, alert,
and well-rested. Effective fatigue management programs must address train crews, dispatchers,
signalmen, track workers, and others – both operating and non-operating personnel. Work
scheduling is a particular problem in on-call operations because of start-time variability, “call”
predictability, and the common use of “shorter-than 24-h work/rest schedules”. Extensive night
operations are incompatible with normal circadian rhythms. Staffing limitations often require
extensive overtime and reduce the effectiveness of any work schedule. These and other
institutional factors significantly contribute to employee sleep deficit and overall fatigue. Lack of
alertness and reduced vigilance are related not only to sleep disruption and resulting sleep
deficits, but also to cognitive workload, workload transition, the physical working environment,
and the design of advanced control systems. Ongoing research into fatigue mitigation and
alertness enhancement strategies and into advanced technologies such as Positive Train Control
(PTC) can lead to improvements. These include better labor–management agreements, more
effective fatigue-related educational programs, improved schedule regularity, and more practical
and adaptable federal laws and regulations.
40. Fatigue and alertness in the United States railroad industry part II: fatigue research in
the Office of Research and Development at the Federal Railroad Administration
Transportation Research Part F: Traffic Psychology and Behaviour, Volume 3, Issue 4,
December 2000, Pages 221-228
Donald Sussman, Michael Coplen
Abstract: The Federal Hours of Service Act of 1907, which regulates the US railroad industry,
imposes both maximum work hours and minimum rest periods. However, this act does not limit
employees' weekly or monthly work hours, restrict the irregularity or unpredictability of on-call
work schedules, or restrict mandatory commuting distances without compensatory time off.
Extensive night work, irregular work schedules, extended work periods with few or no days off,
and the policies, procedures, and agreements that encompass these work scheduling practices, all
evolved within the limited provisions of this act. It is not clear, though, that broad changes in the
hours of service laws are the answer to these problems. Consequently, the Office of Research
and Development at the Federal Railroad Administration, with its Fatigue Research Program, has
embarked upon a non-prescriptive approach to better manage fatigue in the railroad industry.
This program includes the development and implementation of improved fatigue data collection
methodologies, better measurement and evaluation tools, and more effective fatigue
countermeasure strategies. The North American Rail Alertness Partnership (NARAP) has
become an important means for understanding the fatigue-related problems in various
operational settings, and for identifying specific programmatic areas that will better meet the
needs of the industry. The program goals of improving the feasibility, utility and cost
effectiveness of fatigue management are to be realized with the cooperative efforts of the
government, unions, and the railroad industry, particularly though NARAP, and by broadly
disseminating important technical findings through journal publications and conference
proceedings.
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41. Work schedule differences in sleep problems of nursing home caregivers.
Appl Ergon. 2008 Sep;39(5):597-604. Epub 2008 Feb 20.
Takahashi M, Iwakiri K, Sotoyama M, Higuchi S, Kiguchi M, Hirata M, Hisanaga N, Kitahara
T, Taoda K, Nishiyama K.
National Institute of Occupational Safety and Health, 6-21-1, Nagao, Tama-ku, Kawasaki 2148585, Japan. takaham@h.jniosh.go.jp <takaham@h.jniosh.go.jp>
Nursing home caregivers (n=775; 604 women; mean age 33.6 years) were studied to examine
how work schedules affect their sleep. The shift group (n=536) worked under a rotating two-shift
system (n=365), a rotating three-shift system (n=66), or other types of shifts (n=78). The nonshift group included 222 caregivers. Participants completed a questionnaire about working
conditions, sleep problems, health, lifestyle, and demographic factors. The two-shift caregivers
reported the highest levels of difficulty initiating sleep (DIS, 37.6%), insomnia symptoms
(43.0%), and poor quality of sleep (24.9%) among the groups. Adjusted odds ratios for these
problems were significantly greater for the two-shift caregivers than for non-shift counterparts:
DIS (odds ratio 2.86, 95% confidence interval 1.57-5.20), insomnia symptoms (2.33, 1.36-4.02),
and poor sleep quality (2.15, 1.09-4.22). Our data suggest that working under a rotating two-shift
system, which has a longer night shift, is associated with an elevated risk of sleep problems for
nursing home caregivers.
42. Sleepiness on the job: continuously measured EEG changes in train drivers.
Electroencephalogr Clin Neurophysiol. 1987 Jun;66(6):502-11.
Torsvall L, Akerstedt T.
Eleven train drivers participated in the study during 1 night and 1 day journey (4.5 h) over the
same route. Their EEG, EOG and ECG were recorded on portable tape recorders. The EEG
records were subjected to spectral analysis (FFT) and the EOG was scored visually for slow eye
movements (SEMs). The results showed that rated sleepiness increased sharply during the night
journey. A similar pattern was seen for spectral power density in the alpha band, SEM and, to a
lesser extent, also for power in the theta and delta bands. Heart rate was low during the entire
night drive. The day journey showed low values without any trend for all variables. The intraindividual correlations were very high between rated sleepiness and, particularly, alpha and theta
power density, as well as SEM. Further analyses showed that most of the night time increases in
EEG/EOG parameters were confined to the 6 most sleepy subjects. Among these, 4 admitted to
dozing off during the night drive and 2 of these 4 subjects failed to act on signals while
exhibiting large bursts of alpha activity. It was concluded that EEG and EOG parameters closely
reflect variations in sleepiness on the job and that these parameters, together with self-ratings,
demonstrate that severe sleepiness may occur in train drivers during night work.
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43. Age, sleep and irregular workhours: A field study with electroencephalographic
recordings, catecholamine excretion and self-ratings.
Scand J Work Environ Health. 1981 Sep;7(3):196-203.
Torsvall L, Akerstedt T, Gillberg M.
The Laboratory for Clinical Stress Research, Karolinska Institute, Stockholm, Sweden.
Day sleep (after night work) and night sleep (after day work) were studied in two groups of
locomotive engineers aged 25-35 and 50-60 a, respectively. All recordings were made in the
homes of the subjects. For both groups day sleep was reduced by approximately 3.3 h, mainly
affecting rapid eye movement sleep and stage 2 sleep. Diuresis and the excretion of
noradrenaline were increased during day sleep. The ratings of sleepiness were higher after night
work than after day work. Several indices of disturbed daytime sleep correlated significantly
with catecholamine excretion. The age groups differed mainly in that the older subjects had
relatively more stage shifts, awakenings, stage 1 sleep, a higher diuresis, and a higher
noradrenaline excretion during day sleep. It was concluded that night work is detrimental to
sleep and that negative effects are exacerbated by increasing age.
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