Psychological distress

Studies examined prevalence using cut-offs on validated scales. Prevalence rates of psychological distress varied across eight studies: onshore workers (10.0%–36.3%, n=6 studies)18 43 52 58–60 and offshore workers (8.0%–14.0%, n=2 studies).61 62 No study recruited a general population comparison group, only comparing these rates with secondary data sources reflecting the general population (typically ranging from 7.6% to 13%) in five studies.43 52 59 60 62

Depression

Studies showed mixed findings for depression and depressive symptoms in rotation workers. Studies employed a mixture of methods to identify cases of depression within rotation workers, including cut-offs on validated scales18 41 42 50 63 64 and symptoms checklist.58 65–67 Six studies examined the prevalence of depression among rotation workers: onshore workers (28.3%–32.3%, n=3 studies)18 41 42; offshore workers (16.7%–28.0%, n=3 studies).50 63 64 No general population comparison groups were recruited in any study, though two studies41 42 made reference to a secondary source68 reporting prevalence of depressive episodes (4.1%) and affective disorders (6.2%) in Australia. One study recruited both offshore rotation workers (16.7% prevalence) and onshore non-rotation petroleum workers (22.8%), but statistical comparisons were not performed.64

Seven studies examined the levels of depressive symptoms among rotation workers using symptoms checklist.18 42 50 58 65–67 Using the cut-offs belonging to the scales used, the sample means suggested that, on average, rotation workers had minimal depressive symptoms in four studies (one offshore, three onshore)58 65–67 and moderate in one study.18 Two studies with a comparison group compared fathers with onshore rotation jobs with other fathers in cross-sectional surveys, but the difference was not statistically significant.66 67 Two other studies with comparison group compared rotation workers with onshore non-rotation workers and found depressive symptoms to be statistically significantly lower in rotation workers in one study (marginal mean scores 15.5; 95% CI=14.3 to 16.6 vs 19.7; 95% CI=17.0 to 22.4, p=0.01)42 but no differences in the other study.50

Anxiety

Studies regarding anxiety among rotation workers also showed mixed findings. Studies employed a mixture of methods to identify cases of anxiety within rotation workers using cut-offs on validated scales18 50 63 64 and symptoms checklist.58 67 69 70 Four studies examined the prevalence of anxiety among rotation workers18 50 63 64: 22.3% among onshore rotation workers18 and 11.4%–15% among offshore rotation workers.50 63 64 Only one study recruited and compared offshore rotation workers (11.4% prevalence) with onshore non-rotation petroleum workers (13.9%), but statistical comparisons were not performed.64

Furthermore, nine studies examined the level of anxiety symptoms among rotation workers using symptoms checklist.50 58 66 67 69–73 Of these studies, seven reported low level of anxiety symptoms: one study described their samples as having low levels of anxiety symptoms based on their sample means being below some threshold on the scale used58 and remaining studies also reported sample means below any threshold for normal/mild anxiety.66 67 69 71–73

No study recruited a general population comparison group, only comparing the mean scores with secondary data sources and reported comparable scores among onshore rotation workers in one study58 but higher scores among offshore rotation workers in another study.70 Four studies with comparison groups compared rotation jobs with non-rotation workers in cross-sectional surveys: one study found offshore rotation had higher level of anxiety symptoms than onshore non-rotation petroleum workers (3.62±3.42 vs 2.43±2.18, p<0.01),69 but no statistically significant differences were reported in three studies.50 66 67

Stress

Six studies examined levels of stress symptoms among rotation workers using symptoms checklist.18 30 58 66 67 74 Using the cut-offs and scores based on scales used, the sample means suggested rotation workers had low level of stress symptoms in five studies18 30 58 67 74 and moderate in one study.66 Two cross-sectional studies with comparison groups compared fathers working onshore rotation jobs with fathers working non-rotation jobs, but the differences were not statistically significant.66 67 No study recruited a general population comparison group, one study only compared mean scores on Depression, Anxiety and Stress-21 Scale with secondary data sources in non-clinical general population and reported comparable scores among onshore rotation workers, but no statistical comparison was done.58

Emotional exhaustion and worn-out

Four studies examined emotional exhaustion and feeling ‘worn-out’ among rotation workers using symptoms checklist.29 75–77 Both emotional exhaustion and ‘worn-out’, defined by ‘symptoms of emotional liability, tiredness and cognitive confusion’, have been operationalised by the same Worn-out Scale from the General Well-Being Questionnaire.75–77 Based on the mean scores and cut-offs of scales used, the sample means suggested rotation workers had low emotional exhaustion and low ‘worn-out’ in three studies.75–77 One longitudinal study documented a daily increase in emotional exhaustion and decrease in work engagement over the course of up to 28-day onshore rotation work period, but there was no comparison group.29 Only one study with a comparison group compared offshore rotation workers with onshore non-rotation petroleum workers, and found statistically lower worn-out level than in onshore non-rotation oil workers (mean score 13.82 vs 15.11, p<0.001).76 No study recruited general population comparison group, two studies only compared mean scores with secondary data sources in factory workers and reported comparable scores among offshore rotation workers, but no statistical comparison was done.76 77 Qualitative evidence suggested offshore rotation workers experienced mental exhaustion due to the long shift hours associated with rotation work.34

Suicide risk

Only two studies examined suicide risk among rotation workers, and both used the same sample (onshore rotation workers in Australia). In these studies, suicide risk was determined using Beck Hopelessness Scale, with scores above 9 indicating elevated risk for suicide intentions and behaviour. Here, suicide risk prevalence was reported as 26.7%.41 42 One of these studies found suicide risk was lower among onshore rotation mining workers (26.7% prevalence) than onshore non-rotation mining workers (27.4%) (p=0.02).42 No general population comparison groups were recruited, though both studies made reference to a secondary source reporting prevalence of one in six of the general population.41 42 There was no study that examined suicide intention or behaviour among offshore rotation workers.

Psychological well-being

Studies showed inconsistent findings. Studies employed a mixture of methods to examine the levels of psychological well-being within rotation workers using symptoms checklist,54 69 70 78 79 cut-off points on validated scales34 80 and self-reported diagnosis of mental health problems.35 48 Sample mean scores suggested good mental well-being among offshore rotation workers in three cross-sectional studies69 78 79 and a daily diary study also reported low daily use of medication for mental health problems among onshore rotation workers across on-shift and off-shift days.35

Five studies compared psychological well-being of rotation workers with other work group.48 54 69 70 78 Three of the studies with comparison group compared rotation workers with non-rotation workers and found prevalence of mental health problems to be statistically significantly lower in rotation workers in one study (7.7%; 95% CI=4.4% to 11.0% vs 13.0%; 95% CI=12.1% to 13.9%, p<0.01),48 higher mean scores (ie, high levels of poor mental health symptoms) among rotation workers in one study (8.75±3.76 vs 7.64±2.94 ; p<0.05),69 but comparable psychological health complaints in the other study (no statistical analysis was done).78 Two studies did not recruit comparison group, but compared sample mean scores with secondary data source in non-rotation industrial workers and reported comparable levels of mental health well-being among offshore rotation workers, but no statistical comparisons were done.54 70 No study recruited a general population comparison group, two studies compared mean scores with secondary data sources and reported higher mental functioning and mental well-being in offshore rotation workers than in the normative population,34 80 but no statistical comparisons were done.

Similarly, qualitative evidence was also mixed. Eight qualitative studies reported that onshore rotation workers experience high mental distress due to the demands and challenges of rotation work lifestyle34 51 81–86; for instance experiencing isolation and loneliness,83 85 work–home conflicts,34 81–83 family and social disruptions,81 83–85 worries of delegating house chores to partners83 84 and ‘pre-boarding stress syndrome’ characterised by symptoms including anxiety and bad mood in the last days of leave periods.51 However, four of the qualitative studies also reported onshore rotation workers expressed job and life satisfaction with their work, highlighting financial rewards, enough quality time to spend with family/friends on leave periods, freedom from home stressors/chores and less effect on their mood.34 83–85

Job demands

Five studies showed high job demands were associated with poor mental health outcomes.16 29 59 64 76 87 For instance, one cross-sectional study reported increase in job demands was associated with increased level of mental distress.64 Bowers et al in another cross-sectional study also found workers who were stressed by job tasks were more likely to experience higher mental distress than those who were not stressed at all by their job task (OR=6.2; 95% CI=1.8 to 21.2).59 A daily survey study found that increases in workload and emotional demands were associated with a daily increased level of emotional exhaustion.29 Another longitudinal study also found high job demands to be correlated with increased symptoms of work-stress worn-out (indicative of poor well-being) (r=−0.382; p<0.001).76

Two cross-sectional studies identified job type/categories as a predictor of psychological health.69 78 Parkes69 reported working in higher roles such as supervisory or managerial roles was associated with high level of anxiety.

Job control and clarity

Four studies found significant association between job control/autonomy and better mental health outcomes.29 64 76 78 For instance, a daily diary study reported increase in job autonomy was associated with increased levels of engagement.29 Further, a cross-sectional study found increased in job control was associated with decreased level of mental distress.64 Bergh et al in another cross-sectional study found rotation workers’ control over their job was also correlated with less work-stress worn-out (r=−0.472; p<0.001).76

Two cross-sectional studies also found job clarity was associated with better mental health outcomes.64 76 One study showed increased in job clarity was associated with decreased level of mental distress.64 The other study found rotation workers’ clarity on their jobs was also correlated with less work-stress worn-out (r=−0.415; p<0.001).76

Roster characteristics

Three cross-sectional studies found significant associations between roster type/length and shift length with mental health.43 59 63 One study found that the odds of high psychological distress, defined by a score of 22–50 on a scale of 10–50, were higher in workers with 2 weeks on/1 week off roster (OR=2.4; 95% CI=1.7 to 3.4; p<0.001) and 1 week on/1 week off roster (OR=1.6; 95% CI=1.00 to 2.5; p=0.039) compared with a 4 weeks on/1 weeks off roster.59 Another study in offshore workers on long roster cycle found the odds of higher level of anxiety symptoms (defined by a higher score on a scale of 0–21) were higher in those on 56 days on/28 days off than those on 28 days on/28 days off roster cycle (OR=1.53; 95% CI=1.15 to 2.04).63 Additionally, one study found workers who were stressed by the length of their shifts had increased odds of higher psychological distress (OR=2.4; 95% CI=1.2 to 5.1; p=0.017) than workers who were not.59 Another study reported workers on longer shifts (>12 hours) had higher odds of high psychological distress (scores of 22–50 on a scale of 0–50) than those on shorter shifts (<12 hours) (OR=1.61; 95% CI=1.17 to 2.30).43 Similarly, evidence from a qualitative study indicated workers experience mental exhaustion following long shift hours.34

Work–home interference

Four cross-sectional studies have also established high work–home interference (undesired interaction between work and home domains/roles) was associated with poor mental health outcomes.16 38 70 87 For instance, Ljosa et al16 established that increase in levels of shift work–home interference was associated with increased mental distress among offshore rotation workers. Similarly, one study found that increase in stress from work–home interference was associated with increased poor mental well-being.38 Another study also reported that feeling socially isolated while on-site was strongly related to high psychological distress (r²=0.61).52

Similarly, qualitative evidence showed psychological/emotional strain due to social life disruptions34 51 81–84: six studies noted many rotation workers had difficulties balancing work and home/social life, leading to social and domestic conflicts,34 51 81–83 and difficulties in maintaining family and social relationships.81 83 84 Another qualitative study indicated absence from family made rotation workers feel isolated and lonely, and the ‘physical and psychological distance’ caused tension and distrust which put a strain on the relationship with partners.83 Three qualitative studies again indicated rotation workers experience the worries of delegating their domestic responsibilities to their partners83 84 and missing out on family events.34 83 84

Financial situation

Two cross-sectional studies found an association between workers’ financial situation and psychological distress. One study found workers experiencing financial stress were more likely to report high psychological distress (OR=6.0; 95% CI=2.7 to 13.1)59 than those who were not stressed at all by their financial situation. Another study also found that working primarily for financial reasons was associated with increased odds of high psychological distress (OR=1.34; 95% CI=1.12 to 1.61).43

Evidence from three qualitative studies also documented that rotation workers’ relatively high income had become a source of stress due to a perceived lack of control or autonomy over their work and career, but being forced or ‘trapped’ into work rotation due to the financial gain.34 81 83

Remoteness and living conditions

A cross-sectional study found workers stressed from the remoteness of the living environment were more likely to have high psychological distress than those who were not (OR=3.7; 95% CI=1.6 to 8.6).59 Another cross-sectional study found increase in stress from living in a remote environment (including factors such as sharing accommodation, disturbance in living accommodation and lack of privacy) was associated with increased levels of anxiety and poor mental well-being.70

Similarly, qualitative evidence showed that sharing accommodation at work made workers experience stress from the lack of privacy.34

Social support

Five cross-sectional studies found social support was associated with better mental health outcomes.16 42 61 76 88 For instance, one study documented perceived support from supervisors was associated with lower risk of psychological distress (relative risk (RR)=0.76; 95% CI=0.63 to 0.92, p<0.01).61 Likewise another study found increased social support was associated with lower suicidal risk and lower levels of depression.42 Similarly, one study found increased in social support was also associated with decreased in worn-out from work-stress (r=−0.457; p<0.001).76

Similarly, two qualitative studies explored ways of improving the mental well-being of rotation workers and discussed the provision of social support.82 83 Ebert and Strehlow82 further noted the availability of confidential, trustworthy and proactive chaplaincy support on worksite helped break the ‘culture of masculinity’ or stigma attached to seeking help for health, and effectively promoted the mental health of rotation workers. Workers identified support from employers, colleagues and emotional support from family and other rotation families as ways to improve their mental well-being.83

Stigmatisation and bullying

Five cross-sectional studies identified workplace bullying to be associated with poor mental health outcomes.41 42 52 62 73 Two studies documented workers who experienced workplace bullying were more likely to have high levels of suicide risk (OR=2.70; 95% CI=1.53 to 4.76), clinical depression (OR=2.38; 95% CI=1.40 to 4.05)41 and psychological distress (OR=1.49; 95% CI=1.07 to 2.10)62 than those who did not. Likewise, one study found increase in workplace bullying was associated with increased level of anxiety.73 Two other studies reported workers stressed by the fear of workplace stigma attached to mental health problems were much more likely to have high/very high mental distress (OR=23.5; 95% CI=7.5 to 73.2) than those not stressed at all,59 whereas workers with a high perception of the organisation’s commitment to mental health were less likely to have high psychological distress than those who had low perceptions (OR=0.69; 95% CI=0.55 to 0.85).43

Evidence from two qualitative studies similarly highlighted that onshore rotation workers are faced with workplace stigma attached to mental health83 and public stigmatisation of rotation work as being ‘dirty’ and ‘substance misusers’,81 and an underappreciation of how hard rotation work is, which contribute to worse psychological well-being.81 83 Furthermore, three qualitative studies reported rotation worksites were characterised by the ‘culture of masculinity’ which frowns on weakness but upholds hard work, leading to the uptake of behaviours and bullying, and the reluctance to seek help for health and well-being by workers in order to fit in the work environment.34 81 83

Leadership style of managers

Evidence from four studies showed that the leadership style of managers and supervisors is associated with mental health outcomes among workers.59 62 64 87 One longitudinal study identified workers exposed to laissez-faire leadership style, style where managers or supervisors are ‘passive and avoidant’, had higher odds of psychological distress among rotation workers than those who were not exposed (OR=1.69; 95% CI=1.12 to 2.54).62 Similarly, one cross-sectional study reported an increase in the experience of fair and empowering leadership was associated with decreased in mental distress.64 Another cross-sectional study identified workers who were stressed by their immediate supervisors had more increased odds of poor mental health (OR=4.3; 95% CI 1.6 to 11.3) than those who were not stressed at all.59 Chen et al in a cross-sectional study also identified increase in stress from management problems was associated with increased poor mental health among workers.87

Other occupational stressors

Occupational stressors were identified to significantly predict poor mental health outcomes in five studies.10 38 87 89 One cross-sectional study found increase in risk perception was associated with increased levels of anxiety among offshore rotation workers.73 Two other cross-sectional studies found increase in stress from safety concerns was associated with increased poor mental health.38 87 Another cross-sectional study found motion of offshore platforms had a positive relationship with feelings of depression and anxiety.89 Additional cross-sectional study also identified increased in perceived job dissatisfaction was associated with reduced mental well-being.38 Another cross-sectional study found workers satisfied with rotation work had less odds of psychological distress (OR=0.33; 95% CI=0.25 to 0.43) than workers who were not satisfied.43

Job insecurity has also been found to be associated with mental distress. One cross-sectional study reported that rotation workers with increased concerns about job loss were more likely to have high psychological distress (OR=3.17; 95% CI=1.96 to 5.16) than those who were not concerned about losing their jobs.43

Likewise, evidence from two qualitative studies showed that rotation workers are reluctant to report or seek help for their mental health problems due to the fear of losing their jobs.81 83

Perceived physical health and subjective health complaints

Studies showed generally good/very good perceived physical health status among rotation workers. Nine studies examined perceived physical health complaints among rotation workers using self-ratings,34 36 37 39 58 90 91 self-reported use of medication for physical health problems35 and score cut-offs.34 80 Seven studies reported high proportions (73.4%–88.6%) of rotation workers perceived their general physical health as good or very good.34 36 37 39 58 90 91 Additionally, one longitudinal study found low daily use of physical health medication across on-shift days and off-shift days among onshore rotation workers.35 No study recruited a general population comparison group, two studies compared mean scores with secondary data sources and reported higher physical health functioning in offshore rotation workers than in the norm-based population,34 80 but no statistical comparisons were done.

Eight studies examined subjective health complaints among rotation workers using the Subjective Health Complaints Scale,36 37 39 40 62 75 78 92 all within offshore workers. Based on the mean scores on scale used, the sample means suggested low/some subjective health complaints in seven studies.36 37 40 62 75 78 92 One of these was a longitudinal study, reporting no significant changes in the level of subjective health complaints from the start to the end of a 2-week work period.37 However, one cross-sectional study reported high prevalence of subjective health complaints based on one or more complaints in the last 30 days among offshore rotation workers, and that was significantly higher among workers with shift work disorder (SWD) (condition of excessive sleepiness and insomnia) than workers without SWD (100% vs 89.9%; p<0.001).39

Gastric problems

Studies examining gastric problems reported mixed findings. Six studies examined gastric problems among rotation workers using symptoms checklist. Two cross-sectional studies documented prevalence (31%) of general gastric problems including indigestion, heartburns and stomach pains,61 and prevalence of poor appetite (66.8%) and localised epigastric pain (52.3%)10 in offshore rotation workers. Another cross-sectional study reported high prevalence of gastrointestinal complaints based on one or more complaints in the last 30 days among offshore rotation workers, and that was significantly higher among workers with SWD than workers without SWD (87% vs 50.6%; p<0.01).39 However, based on the mean scores of scales used, sample means suggested in two other cross-sectional studies40 93 and one longitudinal study,36 low scores on complaints of gastric problems (ie, low levels) among offshore rotation workers.

Musculoskeletal disorders

Ten studies examined musculoskeletal disorders among rotation workers using symptoms checklist and findings were mixed. Seven of these studies reported prevalence of musculoskeletal disorders: among offshore rotation workers (7.7%–56.3%)15 34 61 77 94 and onshore rotation workers (ranging from 1% headache to 5% pain in the legs).30 Another cross-sectional study reported high prevalence of musculoskeletal pain based on one or more complaints in the last 30 days among offshore rotation workers, and that was significantly higher among workers with SWDs than workers without SWDs (90.9% vs 69.6%; p=0.04).39

Three other studies, based on the sample mean scores of scales used, reported few subjective musculoskeletal complaints.36 40 44 But one of these studies compared musculoskeletal complaints among age groups and reported high levels of musculoskeletal complaints among offshore rotation workers aged above 50 years compared with younger workers (16.93±45.19 vs 1.71±5.61, p<0.001).40 Another of the studies found complaints of musculoskeletal pain symptoms increased across a 1-year work period.44 The knees, neck, lower back and shoulder were the common reported locations of musculoskeletal problems among rotation workers in four studies.15 44 77 94

Qualitative evidence similarly showed that onshore rotation workers frequently experienced physical pain and commonly reported were muscle and joint pains, neck and back pains, and leg and foot pains.81

Job demands

Two studies reported job demands were associated with perceived poor physical health status and health complaints.78 93 One cross-sectional study reported an increase in physical workload was associated with increased level of physical strain.93 Another cross-sectional study found an increase in job demand of repetitive work was associated with decreased perceived good physical health status.78

Job and roster type

Four cross-sectional studies documented job types to be associated with perceived physical health status and complaints.61 78 94 95 For instance, Parkes identified working in managerial (RR=1.88; 95% CI=1.21 to 2.91, p<0.01), construction (RR=1.84; 95% CI=1.17 to 2.89, p<0.01) and drilling (RR=1.64; 95% CI=1.11 to 2.42, p<0.05) roles was associated with higher risk of headache complaints compared with working in maintenance roles.61 Workers on drilling roles (RR=1.68; 95% CI=1.14 to 2.47, p<0.01) were also at increased risk of muscular complaints, while working in catering role (RR=0.50; 95% CI=0.28 to 0.89, p<0.05) was associated with less muscular complaints compared with working in maintenance roles.61 Another study found working in maintenance and modification role was related to perceived poor general health, while working accommodation role was related to higher symptoms of ill-health compared with other work groups.95

Two cross-sectional studies found rotation work roster type to be associated with physical health complaints.61 94 One of the studies reported working a swing shift (nights-to-days shift) roster was associated with higher risk of gastric problems (RR=1.36; 95% CI=1.00 to 1.84, p<0.05) compared with working on day shift.61 The other study found working tour-scheduling jobs (without regular work hours) to be related to more muscular complaints.94

Social support

One cross-sectional study found an increase in social support was associated with decreased level of physical strain.93 Another cross-sectional study further identified workers with perceived high support from their supervisors were at lower risk of gastric problems (RR=0.82; 95% CI=0.72 to 0.94; p<0.01)61 and complaints of headaches (RR=0.83; 95% CI=0.73 to 0.94, p<0.01).61

Leadership style

One cross-sectional study found management prioritisation of safety issues (r=−0.21; p<0.01) and authentic leadership style (r=−0.21; p<0.01) to be associated with fewer subjective health complaints among workers.96

Other occupational stressors

Experiences of occupational stress were also identified to be associated with perceived physical health status and health complaints. Two cross-sectional studies identified perceived safety climate (perceived importance placed on safety in an organisation) to be associated with subjective health complaints.15 92 For instance, one of the studies identified workers who were stressed by safety climate were identified to be more likely to have more muscular pains in the low back (OR=1.29; 95% CI=1.05 to 1.59), neck (OR=1.53; 95% CI=1.26 to 1.93), knees (OR=1.59; 95% CI=1.24 to 2.06) and shoulder (OR=1.54; 95% CI=1.20 to 1.99) compared with those who were not.15

Further two cross-sectional studies identified risk perception to be associated with physical health complaints.93 96 One study found an increase in risk perception was associated with increased physical strain.93 Likewise, the other study also reported stress from risk perception was positively related to more health complaints (r=0.24; p<0.01).96

Similarly, one cross-sectional study reported increase in stress from communication and participation in work decisions was associated with increased physical strain.93 Additionally, another cross-sectional study found increase in occupational stress was also associated with increased complaints of ulcer-like symptoms.10

Two cross-sectional studies identified stress from physical work environment was associated with muscular pain complaints.15 61 For example, one of the studies reported workers who experienced high stress from the physical work environment were more likely to complain of muscular pains in the low back (OR=1.37; 95% CI=1.11 to 1.69), neck (OR=1.43; 95% CI=1.14 to 1.79) and shoulder (OR=1.32; 95% CI=1.03 to 1.68) compared with those who did not.15

One cross-sectional study also found workers who experienced stress from the interface between job and family/social life were more likely to have muscular pains including in the low back (OR=1.46; 95% CI=1.18 to 1.82) and shoulder (OR=1.35; 95% CI=1.02 to 1.71) compared with those who did not.15 Furthermore, one cross-sectional study found increase in workers’ satisfaction with employee relations and extrinsic satisfaction with working conditions was associated with increased level of strain.93

Perceived sleep problem

Studies’ findings were inconsistent. Seven studies examined the levels of perceived sleep problems using self-rating39 58 61 and checklist.30 74 92 93 Of these, three cross-sectional studies reported prevalence ranging from 45% to 79.4% for perceived sleep problems during work periods.39 58 61 Based on the sample mean scores of scales used, three studies reported scores below the threshold for subjective sleep problems (ie, low levels),30 74 92 whereas one study reported moderate levels for sleep difficulties93 during work periods. Similarly, one longitudinal study also reported workers show no sleep deterioration over a 2-year period.30

Evidence from a qualitative study showed offshore workers experience poor sleep at the first and the last 2–3 days of the leave periods.51

Sleep duration

Evidence from the studies was mixed but generally suggested short sleep duration in rotation workers during work periods. Fourteen studies examined sleep duration among rotation workers.31 33 47 65 71 72 94 97–103 Of these, two cross-sectional studies reported that 33.1%–51.2% of workers slept for less than 6 hours during work periods.65 94 Four longitudinal studies33 47 101 102 further reported shorter sleep duration of less than 7 hours during work periods; with offshore rotation workers reporting an average acute sleep loss of 1.32 hours per day (95% CI: 88.6 to 94.9 min), and chronic sleep loss of 21.20 hours (SD=08.10 hours) per rotation or work period.33 Seven of the studies compared and found shorter sleep duration during on-shifts than on off-shifts, for both day and night shifts.31 71 72 97–100 103 For instance, one longitudinal study found ‘total sleep time’ for days off (7.0±1.9 hours) was longer than day (6.0±1.0 hours) and night (6.2±1.6 hours) shifts (p<0.001).97 Another longitudinal study reported shorter ‘total sleep time’ during work periods for both day (6.1±1.0 hours) and night (5.7±1.5 hours) shifts than days off (7.3±1.2 hours) (p<0.0001).98 However, in two of the studies comparing sleep among offshore rotation workers and non-rotation onshore oil workers, one cross-sectional study showed longer sleep duration among offshore workers than onshore petroleum workers during day (6.84±1.00 hours vs 6.58±0.96 hours) and night (6.57±1.38 hours vs 5.62±1.33 hours) shifts (p<0.001),103 while another showed long sleep duration on night shifts (7.20±1.3 hours vs 5.86±1.26 hours) but shorter on day shifts (6.99±1.18 hours vs 7.07±0.82 hours) than onshore petroleum workers (p<0.0001).100

Sleep quality

Studies’ findings were mixed but generally suggested poor sleep quality in rotation workers during work periods. Thirteen studies examined sleep quality among rotation workers. Using cut-off points on validated scales, three studies found prevalence (67%–72%) of poor sleep quality among offshore rotation workers.65 80 104 Ten of the studies examined sleep quality during work and leave periods. In eight of the studies, sample means based on the scales used suggested generally poorer sleep quality on both day shifts and night shifts compared with leave periods.31 35 37 71 72 99 100 103 For instance, one longitudinal study found sleep quality was lower (on a scale of 1–5) during on-shift periods (3.3±0.8) compared with pre-on-shift (3.5±0.8) and post-on-shift (3.5±0.8) days (p<0.001).31 However, two studies showed better sleep quality during work periods.44 97 For example, one longitudinal study found no significant differences in sleep quality during on-shifts (both day and night shifts) and off-shift days among onshore rotation workers.97 The other longitudinal study among onshore rotation workers found high sleep efficiency and good sleep quality but decreased towards the end of the work period.44 Furthermore, two cross-sectional studies compared sleep quality and found better sleep quality among offshore workers than onshore petroleum workers during day shifts103 and night shifts.100 103

Sleepiness and insomnia

Studies show sleepiness and insomnia among rotation workers. Five studies examined sleepiness and insomnia among rotation workers using cut-off points37 39 65 and symptoms checklist.31 37 39 44 65 Two of these studies found a 23.3%–27.0% prevalence of shift work disorder characterised by excessive sleepiness and insomnia,39 65 and one of the studies reported 67% of offshore rotation workers had insomnia.65 Based on the mean scores of scales used, the sample means suggested high levels of sleepiness and insomnia during work periods in three studies.31 37 44 For example, one longitudinal study found more insomnia complaints (higher score on a scale of 0–42) at the end of work periods compared with the start of a 2-week work period (13.8±9.6 vs 7.1±6.8; p<0.0005).37 Another longitudinal study reported complaints of insufficient sleep increased across a 1-year period, while severe sleepiness accumulated across the work period and was highest on the last morning shifts during work periods.44 Additionally, another longitudinal study found morning sleepiness levels were highest during work periods, while evening sleepiness also increased during offshore work periods and decreased during post-offshore work period.31

Fatigue

Findings from studies suggested high fatigue during work periods. Seven studies examined fatigue among rotation workers using cut-off points,34 self-ratings32 33 44 and symptoms checklist.47 74 98 Based on the mean scores of scale used, the sample means suggested high levels of fatigue during work periods in five studies32 33 44 47 98 and generally low fatigue in one study.74 Another cross-sectional study reported 73% of offshore rotation workers indicated experiencing prolonged fatigue during on-shift periods.34 A longitudinal study reported fatigue was lower during pre-shift than post-shift periods, but increased and accumulated faster by 0.03 points per day (on a 1–9 scale) (95% CI=0.00 to 0.07; p=0.037) in post-shifts compared with pre-shift periods.33 A similar longitudinal study found that daily subjective post-shift fatigue increased by 0.05 points per day (on a 1–9 scale) (95% CI=0.02 to 0.08, p=0.004) and over a 2-week offshore work period,32 though daily objective fatigue (eg, performance on a reaction time task measured by reaction times) was stable (1.00; 95% CI=0.99 to 1.00) over the course of the offshore work period.32 Another longitudinal study reported among onshore rotation workers critical levels of fatigue at the end of the day 1–3 of night shifts and after the 7th day of a day shift.47 Furthermore, onshore rotation workers reported higher pre-sleep and post-sleep fatigue and a significantly higher post-sleep fatigue ratings during on-site days for both day and night shifts than days off in another longitudinal study.98

Similarly, two qualitative studies reported onshore and offshore rotation workers indicated fatigue as one of their main occupational health and safety issues.34 105 Another qualitative study reported fatigue among some onshore rotation workers which was indicated to affect their mood and social life at home.84

Shift/roster pattern

Evidence showed working night shift and/or swing/rotation shift was likely to be associated with more sleep problems than working day shifts. Four studies examined the relationship between general sleep problems and roster/shift patterns.57 61 106 Three of the studies found night/swing shift to be related to sleep problems.57 61 106 One cross-sectional study found workers on night/swing shift were at increased risk of more sleep problems compared with day workers (RR=1.81; 95% CI=1.36 to 2.42, p<0.001).61 Additionally, one longitudinal study reported sleep efficacy was higher among offshore day shift workers than night (93% vs 88%; p<0.001) and swing shift workers (93% vs 88%; p<0.05).106 However, a longitudinal study reported subjective sleepiness did not differ between day, night and swing shift work periods.107

Four studies examined the relationship between sleep duration and roster/shift patterns. Three of studies found night and/or swing shifts to be related to short sleep duration57 71 106 For instance, one cross-sectional study found workers on a fixed-day shift reported significantly longer sleep duration than those on swing shift (nights-to-day shift; 7 nights/7 days).71 Another cross-sectional study found more night/swing shift workers to have short sleep episodes than day shift workers (44.1% vs 16.3%; p<0.01).57 However, a cross-sectional study among offshore rotation workers documented longer sleep duration in swing shift workers than day shift workers.40

Eight studies examined the relationship between sleep quality and roster/shift patterns and evidence was unclear. Three of the studies reported night and/or swing shift was related to poor sleep quality.71 90 108 For instance, one longitudinal study found night shift and swing shift workers reported poorer sleep quality throughout the 14 days of leave periods than in day shift workers.90 In contrast, two studies found better sleep quality working night and swing shifts.100 106 One of the studies showed better sleep quality (higher score on a scale of 0–6) in night shift workers than day shift workers (3.66±1.52 vs 3.20±1.84; p<0.01).100 The other longitudinal study reported better sleep quality (higher score on a scale of 1–5) during swing shift than during day (3.40±0.49 vs 3.37±0.61; p<0.01) and night shifts (3.40±0.49 vs 3.32±0.62; p<0.05) for the first week of work period.106

Three other studies found no significant relationship between sleep quality and shift schedules.37 97 104 For example, one longitudinal study reported no significant differences in the proportion of workers with better sleep quality at the start (27.8% vs 26.9%; p=0.96) and end (33.3% vs 44.1%; p=0.09) of the work period between day and swing shifts.37 Another cross-sectional study reported no differences in the proportion of workers with impaired sleep quality working fixed day (66.1%), fixed night (66.6%) and swing (83.3%) shifts (p=0.34).104

Only two studies examined relationship between fatigue and shift/roster pattern. A longitudinal study found pre-sleep fatigue was higher in working night shifts compared with day shifts, but recovery of sleep on night shift was higher than day shift.98 In contrast, another longitudinal study reported no significant differences in fatigue measures such as physical and mental tiredness during night shift, and swing shift compared with day shift workers.90

Qualitative evidence study showed perceived high fatigue among onshore rotation attributed to roster patterns and sleep difficulties which improved after a change of roster from a rapid swing roster 7 nights on/7 days on/7 days off to a longer swing roster of 8 days on/6 days off/8 nights on/6 days off.105 Another qualitative study suggested high-perceived fatigue was attributed to the long shift hours of rotation work.34

Job demand and control

Two studies reported job demands and control were associated with sleep problems.11 99 One cross-sectional study reported increase in workload was associated with decreased sleep duration.99 Furthermore, increase in job demands among older rotation workers was associated with decreased sleep quality than in their younger counterparts.99 Similarly, Parkes,11 in a cross-sectional study, reported increase in job demand was associated with reduced sleep duration in rotation workers who work overtime. One cross-sectional study reported increase in job control was also associated with increased sleep quality.99

Three cross-sectional studies reported working overtime was associated with short sleep duration and poor sleep quality.11 71 72 For instance, one of the studies found offshore rotation workers working overtime of >16 hours per week during night shifts were associated with shorter sleep duration than those not working overtime.71 Another study found that an increase in working overtime was associated with decreased sleep quality among day shift workers.11

Social support

Two cross-sectional studies found social support was associated with longer sleep duration and better sleep quality.11 99 One of the studies found increase in social support was related to increased sleep quality and sleep duration in day shift rotation workers.99 The other study reported increase in support from supervisors was associated with increased sleep duration in day shift workers working overtime.11

Other occupational stressors

One cross-sectional study found increase in risk perception to be associated with reduced sleep quality.108 Further, the study reported increase in perceived safety climate was associated with increased subjective sleep quality.108

Three cross-sectional studies reported adverse physical environment was associated with sleep problems.11 61 99 For instance, one of the studies reported workers with high perception of adverse physical environment had increased risk of sleep problems (RR=1.16; 95% CI=1.01 to 1.33, p<0.05).61 Two of the studies reported increase in perceived adverse physical environment was associated with decreased sleep quality among offshore rotation workers.11 99

A longitudinal study also found the increase in motion of offshore platforms was related to high incidence of physical tiredness, mental tiredness, poor sleep quality and short sleep duration.89 Similarly, qualitative evidence showed that rotation workers perceived sleep disturbances to be caused by work environmental stressors such as motion and noise of platforms, and accommodation arrangements.34

Alcohol consumption

Studies showed higher alcohol consumption among rotation workers on off-shift days than in other workgroups and in the general population. Eight studies described the regular alcohol intake of rotation workers17 34 35 54 55 80 109: the proportion of consuming ‘any’ alcohol ranged from 22.1% to 84.1% across three studies17 34 109 and the proportion consuming alcohol above recognised safe limits ranged from 16.0% to 53.4% across four studies.17 54 55 80 One longitudinal study found alcohol consumption was typically within the healthy consumption limit (average 1.05 standard drinks/day) among onshore workers across both on-shift and off-shift days.35

Furthermore, two longitudinal studies reported inconsistent drinking among rotation workers during on-shift days; one documented that drinking on on-shift days was at high-risk levels (median 3.0 (IQR 2.0–6.0) standard drinks per session),17 while the other reported daily drinking of average: 2 (1.7–2.8 units/day) during day shifts and 1 (median 0.6–1.4 units/day) during night shifts.47 Similarly, two other longitudinal studies compared drinking on on-shift days with off-shift days35 47; and one of the studies reported drinking was less during on-shift days compared with off-shift days.35 Muller et al47 also reported rotation workers on off-shift days engage in high-risk drinking with a median of 6 (IQR 3–10) standard drinks per session and a median of 4 (IQR 2–6) standard drinks per session during on-shift.

Additionally, three cross-sectional studies compared drinking in rotation workers with non-rotation workgroups and the general population and found drinking to be consistently higher among rotation workers.48 55 67 One study with comparison group compared rotation workers with onshore non-rotation workers and found more rotation workers drink alcohol at levels that have high risk of both short-term health (more than four alcoholic drinks per day) (29.8%; 95% CI=22.8% to 36.8% vs 21.5%; 95% CI=20.2% to 22.9%) and long-term health (more than two alcoholic drinks per day) (64.7%; 95% CI=57.5% to 71.9% vs 50.9%; 95% CI=49.4% to 52.4%) harm (p<0.01).48 Another study did not recruit a comparison group, only comparing the means of alcohol intake per week among offshore rotation manual workers with secondary data sources in onshore non-rotation manual industrial male workers, and reported statistically significantly higher mean units of alcohol intake per week among offshore rotation workers (49.3 units vs 21.4 units, p<0.005).55

One study recruited a general population comparison group, compared onshore rotation workers with non-rotation fathers and found higher alcohol intake scores on Alcohol Use Disorders Identification Test Scale (ie, high alcohol intake) in rotation workers than in non-rotation work fathers (5.52±3.97 vs 3.50±2.86, p<0.05).67 Another study did not recruit a general population comparison group, only comparing the prevalence of drinking among offshore rotation workers with secondary data source among general male population, and reported higher prevalence of heavy drinkers among offshore rotation workers (approximately 30% vs 10% heavy drinkers).55

Similarly, two qualitative studies84 110 described onshore work camps as having a strong ‘culture of drinking’,110 and another qualitative study49 noted some offshore workers indicated that the high levels of alcohol consumption among offshore workers should change.

Illicit drug use

Studies examining drug use among rotation workers were limited. Only two cross-sectional studies examined drug use and reported mixed findings: one cross-sectional study found 33.8% of onshore mining rotation worker were illicit drug users;43 however, another cross-sectional study reported 5.2% of offshore rotation workers were illicit drug users.80

Smoking

Studies examining smoking suggested higher smoking among rotation during on-shift days, than off-shift days and non-rotation workgroups. Fourteen studies described regular smoking in rotation workers and of these, 12 studies showed prevalence of smoking ranging from 17.7% to 47.1% across onshore and offshore rotation workers.34 37 47 48 54 80 97 103 104 109 111 112 One cross-sectional study reported a low proportion (3.3%) of smokers among onshore rotation workers.58 Two studies examined the number of cigarettes smoked and reported rotation workers smoked on average 13.22±8.46 cigarettes per day across both on-shift and off-shift days in a daily diary study35 and mean pack of 3.04±1.9 per day during on-shift days in a cross-sectional study.34

Two cross-sectional studies with comparison groups compared smoking among rotation workers with other non-rotation workgroups and reported smoking prevalence to be consistently higher among rotation workers than onshore non-rotation petroleum workers (33.6% vs 20.6%; p<0.001)103 and other employment arrangements (26.7%; 95% CI=20.5% to 33.0% vs 17.4%; 95% CI=16.3% to 18.5%, p<0.01).48 One daily study examined smoking during on-shift days and off-shift days and reported rotation workers during on-shift days significantly smoke more cigarettes compared with off-shift days.35

Likewise, evidence from two qualitative studies showed smoking was common on-shift days but not a behaviour accepted by all workers,34 with some workers suggesting smoking behaviour should change.49

Physical activity

Studies reviewed suggested rotation workers engage in physical activity. Six studies examined the prevalence of physical activity among rotation workers17 58 80 91 94 109: five studies reported proportions ranging from 46.7% to 97.0% to engage in regular physical activity/exercise,17 58 80 91 94 but one other study reported a high proportion (63.1%) of offshore rotation workers do not engage in any leisure-time exercises after work.109 Four studies examined physical activity/exercise during either on-shift days17 47 94 and off-shift days,47 91 and documented high levels of physical activity/leisure time exercises of at least 2 or more days per week. Two longitudinal studies compared physical activity on on-shift days with off-shift days.35 47 Rebar et al35 reported workers during on-shift days engage in fewer minutes of exercises and relaxations compared with off-shift days, but Muller et al47 reported rotation workers engaged in >30 min of vigorous exercise for more days on on-shift days (median 5 days per week) against median 4 days per week during off-shift days.

One cross-sectional study with comparison groups examined physical activity/exercise among the rotation work and non-rotation workgroups, and reported the proportion of rotation workers who engaged in inadequate physical activity/exercise during leisure time or work (<30 min of physical activity) was not statistically different from that of other employment arrangements (40.4%; 95% CI=33.5% to 47.4% vs 46.2%; 95% CI=44.8% to 47.6%, p>0.05).48

Qualitative evidence was mixed for onshore and offshore workers. A qualitative study reported that most onshore rotation workers engage in sporting activities more than once a week.110 However, another qualitative study discussed how some offshore rotation workers emphasised the need for a change in behaviour toward increasing physical activity.49

Diet/nutrition and BMI

Studies suggested poor nutrition or eating behaviour among rotation workers at worksites. Four studies reported perceived poor food/diet quality during work periods.34 35 53 56 Oshaug et al53 reported high consumption of fats and carbohydrates at offshore worksites. Another cross-sectional study found a large proportion of offshore rotation workers (45.1%) did not meet the dietary requirement of healthy eating of fruits and vegetables (five per day fruit and vegetable intake) during on-shift days.80 A cross-sectional study compared nutrition intake on-shift with the general dietary recommendations and reported offshore workers’ diet may in the long term predispose them to coronary artery disease.53 One longitudinal study compared onshore workers’ perception of nutrition on on-shift days with off-shift days and reported workers during on-shift days perceived their nutritional intake to be poorer compared with off-shift days .35 One cross-sectional study examined the diet among the onshore rotation workers and other workgroups and reported high proportions of workers consume insufficient fruits (48.9% vs 47.7%) and vegetables (87.7% vs 87.9%), but there was no difference between rotation workers and other non-rotation employment.48

Similarly, two qualitative studies34 49 also highlighted the unhealthy eating behaviours of offshore rotation workers, and workers indicated the unhealthy behaviour should change.49

Sixteen studies reported an average BMI of 26.6±3.1 kg/m² (range 22.7–28.9)31 33 34 45–47 57 65 94 97 101 102 107 111–113 indicating rotation workers are usually overweight. Eight studies further reported a large proportion (40.0%–79.3%) of rotation workers as being overweight.34 46 48 58 80 111 112 114 Six studies also reported a large proportion (5.5%–30.0%) of rotation workers as being obese.34 46 80 111 112 114

Three studies compared the BMI of rotation workers with other populations.46 48 114 One cross-sectional study compared onshore rotation workers with non-rotation workgroups and found a higher proportion of overweight and obesity among rotation workers than in non-rotation workgroups (79.3%; 95% CI=73.2% to 85.5% vs 68.0%; 95% CI=66.7% to 69.4%, p<0.01).48 No study recruited a general population comparison group, only comparing BMI with secondary data sources of the general population, found statistically significantly higher prevalence of overweightness/obesity in offshore rotation workers than the general population.46 114 For instance, one of the studies found higher prevalence of overweightness among rotation workers aged 40–49 years compared with the same age group in the general population (66.2% vs 50.0%, p<0.05).46

Social support

One cross-sectional study found offshore rotation workers who lack social support from supervisors were less likely to smoke (OR=0.34; 95% CI=0.18 to 0.65), and those who lack support from friends were less likely to consume alcohol (OR=0.54; 95% CI=0.32 to 0.96) compared with those who had support.109 Further, the study found workers who lack support from both supervisors (OR=1.74; 95% CI=1.113 to 2.65) and friends (OR=1.68; 95% CI=1.06 to 2.42) were more likely not to engage in leisure-time physical activities.109

Evidence from two qualitative studies84 110 suggested alcohol consumption in onshore mining rotation workers at work camps was promoted by a ‘culture of drinking’ that influences workers to take part in drinking if they were to fit in the social work environment.84

Occupational stress

One cross-sectional study found workers who were stressed from the interface between job and family/social life (OR=1.32; 95% CI=1.02 to 1.70) and organisational structure (OR=1.35; 95% CI=1.06 to 1.74) were more likely to be current consumers of alcohol compared with those who were not stressed.109 Further, the study found workers who experience high stress from safety concerns were less likely to smoke (OR=0.74; 95% CI=0.58 to 0.94) and more likely not to undertake leisure-time physical activities (OR=1.44; 95% CI=1.16 to 1.79) compared with those who did not.109

Job type

One cross-sectional study demonstrated job type, that is, working as a manual worker was significantly related to higher alcohol consumption than those in executive roles (49.3 vs 29.5 mean units per week; p<0.005).55

Other working conditions

Qualitative evidence also cited improvement and maintenance of exercise facilities49 110 and other work-related characteristics including time constraints due to ‘long shift hours and travel times’ as barriers to engaging in physical activities/exercises.110 Two other qualitative studies explored rotation workers’ perception of a healthy diet34 49 and indicated workers perceived unhealthy eating of rotation workers to be connected to the availability of unhealthy food or easy access to unhealthy foods at worksites.