Importance of an Integrated Assessment of Functional Disability and Work Ability in Workers Affected by Low Back Pain

Background

This study examines the relationship between functional disability and work ability in workers affected by low back pain (LBP) through an analysis of correlations between the Oswestry Disability Index (ODI) and Work Ability Index (WAI). The role of personal and work factors on functional disability/work ability levels has also been studied. LBP is the most common musculoskeletal problem and a major disabling health problem worldwide. Its etiology is multifactorial. Multidisciplinary approaches may help reduce the burden of pain and disability and improve job continuity and reintegration at work.

Methods

A cohort of 264 patients affected by LBP from an Italian outpatient clinic were included in a clinical diagnostic/therapeutic trial aiming at rehabilitation and return to work through an integrated investigation protocol. Data were collected during the first medical examination using anamnestic and clinical tools. The final sample is composed of 252 patients, 57.1% man, 44.0 % blue collars, 46.4% with the high school degree, 45.6% married.

Results

WAI and ODI reported a negative and fair correlation (r = -0.454; p = .000). Workers with acute LBP symptoms have a higher probability of severe disability than those with chronic LBP symptoms. White collars without depressive symptoms reported higher work ability - even in chronic disability conditions-than those with depressive symptoms.

Conclusion

The study found that ODI and WAI have a convergent validity and this suggests that the two tools measure capture distinctive aspects of disability related to personal, environmental, and occupational characteristics. The most important and modifiable prognostic factors found for ODI and WAI were depressive symptoms, workday absence, and intensity of back pain. The study also found a mild association between age and ODI. The study's findings highlight the importance of using a multidisciplinary approach to manage and prevent disability due to LBP.

Relationship Between Occupational Safety and Health Policy Principles, Organizational Action on Work-related Stress and the Psychosocial Work Environment in Italy

Background

It is acknowledged that legislation acts as a motivator for organizational action on psychosocial risks. Our study aims to provide evidence on the relationship between key occupational safety and health (OSH) policy principles and organizational action on work-related stress, and, in turn, with reported employee job demands and resources and their experience of work-related stress. We focus on Italy where specific legislation and practices on work-related stress were introduced in 2008 which are underpinned by these key OSH policy principles.

Methods

Secondary analysis of the Italian samples from the employer ESENER-2 and employee 6th EWCS surveys was conducted, using path analysis in structural equation modeling (SEM) linking the two datasets.

Results

We found a strong statistically significant relationship between OSH policy principles and organizational action on work-related stress (C.I. = .62-.78 p < .001). The existence of an organizational action plan on work-related stress was found to be significantly associated with more reported job resources (C.I. = .02-.24, p < .05) but these were not found to be significantly associated with less work-related stress. No significant association was found between having an organizational action plan for work-related stress and reported job demands. However, job demands were significantly related to reported work-related stress (C.I. = .27-.47, p < .001).

Conclusions

Findings add support to the call for specific legislation on work-related psychosocial risks and highlight how an organizational OSH culture underpinned by key OSH principles, and awareness/competence development on psychosocial risk management can have a positive effect on organizational action. However, further support needs to be provided to organizations around developing primary prevention interventions at the organizational level with the aim of reducing job demands.

Systematic Violence Monitoring to Reduce Underreporting and to Better Inform Workplace Violence Prevention Among Health Care Workers: Before-and-After Prospective Study

BACKGROUND

Monitoring workplace violence (WPV) against health care workers (HCWs) through incident reporting is crucial to drive prevention, but the actual implementation is spotty and experiences underreporting.

OBJECTIVE

This study aims to introduce a systematic WPV surveillance in 2 public referral hospitals in Italy and assess underreporting, WPV annual rates, and attributes "before" (2016-2020) and "after" its implementation (November 2021 to 2022).

METHODS

During 2016-2020, incident reporting was based on procedures and data collection forms that were neither standardized between hospitals nor specific for aggressions. We planned and implemented a standardized WPV surveillance based on (1) an incident report form for immediate and systematic event notification, adopting international standards for violence definitions; (2) second-level root cause analysis with a dedicated psychologist, assessing violence determinants and impacts and offering psychological counseling; (3) a web-based platform for centralized data collection; and (4) periodic training for workforce coordinators and newly hired workers. We used data from incident reports to estimate underreporting, defined as an observed-to-expected (from literature and the "before" period) WPV ratio less than 1, and the 12-month WPV rates (per 100 HCWs) in the "before" and "after" periods. During the latter period, we separately estimated WPV rates for first and recurrent events.

RESULTS

In the "before" period, the yearly observed-to-expected ratios were consistently below 1 and as low as 0.27, suggesting substantial violence underreporting of up to 73%. WPV annual rates declined in 1 hospital (from 1.92 in 2016 to 0.57 in 2020) and rose in the other (from 0.52 to 1.0), with the divergence being attributable to trends in underreporting. Available data were poorly informative to identify at-risk HCW subgroups. In the "after" period, the observed-to-expected ratio rose to 1.14 compared to literature and 1.91 compared to the "before" period, consistently in both hospitals. The 12-month WPV rate was 2.08 (95% CI 1.79-2.42; 1.52 and 2.35 in the 2 hospitals); one-fifth (0.41/2.08, 19.7%) was due to recurrences. Among HCWs, the youngest group (3.79; P<.001), nurses (3.19; P<.001), and male HCWs (2.62; P=.008) reported the highest rates. Emergency departments and psychiatric wards were the 2 areas at increased risk. Physical assaults were more likely in male than female HWCs (45/67, 67.2% vs 62/130, 47.7%; P=.01), but the latter experienced more mental health consequences (46/130, 35.4% vs 13/67, 19.4%; P=.02). Overall, 40.8% (53/130) of female HWCs recognized sociocultural (eg, linguistic or cultural) barriers as contributing factors for the aggression, and 30.8% (40/130) of WPV against female HCWs involved visitors as perpetrators.

CONCLUSIONS

A systematic WPV surveillance reduced underreporting. The identification of high-risk workers and characterization of violence patterns and attributes can better inform priorities and contents of preventive policies. Our evaluation provides useful information for the large-scale implementation of standardized WPV-monitoring programs.

Promoting health and productivity among ageing workers: a longitudinal study on work ability, biological and cognitive age in modern workplaces (PROAGEING study)

BACKGROUND

Large changes in ageing population and in retirement age are increasing the number of older people in the workforce, raising many challenges for policymakers in promoting employment opportunities and health for older workers. In this respect, longitudinal assessments of workability, well-being perception and cognitive skills over time may allow to detect factors influencing workers' health. Moreover, new available molecular markers permit the measurement of biological age and age-related changes. Most studies analysed one aspect at time (psychological, biological, labour productivity), without considering their interaction. Aims of the study are to evaluate the relationship between workability, cognitive skills, and biological age in a population of ageing workers; to conduct a cross-sectional analysis to assess the impact of occupational exposures on workability, cognitive skills, and biological age; to evaluate inter-individuals changes in a prospective analysis with a re-evaluation of each worker.

METHODS

Our study plans to enrol 1000 full-time workers, aged over 50, undergoing the medical surveillance required by the current Italian Legislation. Data collection includes information about: (a) work ability and psychosocial risk factors (work ability index, HSE Management Standard-21 item, Utrecht Work Engagement Scale, World Health Organisation-Five, Well-Being Index, job satisfaction, general well-being, technostress); (b) cognitive skills (Stroop Color and Word test, Simon task, Corsi's block-tapping test, Digit span test); (c) sleep habits and psychological well-being (Pittsburgh Sleep Quality Index, Insomnia Severity Index, Ford Insomnia Response to Stress Test; Symptom Check List 90, Psychological Well-Being Index, Profile of Mood State, Beck Depression Inventory, Beck Anxiety Inventory, Perceived Stress Scale, Brief COPE); (d) biological age (telomere length, DNA methylation) for 500 workers. All workers will repeat the evaluation after one year.

DISCUSSION

This study aims to increase our knowledge about interactions between work ability, cognitive ability, well-being perception and psychological status also by including molecular markers, with a longitudinal and multidisciplinary approach. By bringing better insights into the relationship between risk factors and their impact on perceived and biological health, this study also aims at identifying possible interventions and protective measures to ensure aged workers' well-being, consistent with all the eminent calls for actions promoted by key International and European labour organizations.

The Effect of Transitioning to Remote Working in Patients Affected by Chronic Low Back Pain: A Cross-Sectional Study

OBJECTIVE

To assess the effect of transitioning to remote working during the coronavirus disease 2019 pandemic in a population of adults affected by chronic low back pain (cLBP).

METHODS

An online questionnaire was sent by email to teleworkers affected by cLBP. Demographic data, remote working features and tasks, and LBP burden were analyzed. The psychological burden of remote working was evaluated with the World Health Organization Five Well-Being Index and the Patient Health Questionnaire-2. LBP severity was evaluated using a visual analogue scale. LBP-related disability was assessed using the Oswestry Disability Index. The effect of LBP on working capacity was examined with the Occupational Role Questionnaire. Independent risk factors related to LBP worsening were identified using a multivariate logistic regression model.

RESULTS

During remote working, LBP severity was significantly higher compared to previous in-person working (p < 0.0001), as well as average weekly work hours (p < 0.001). Furthermore, the risk of LBP worsening was associated with higher depression scores (odds ratio [OR], 1.38; 95% confidence interval [CI], 1.00-1.91; p = 0.048), increased stress levels (OR: 3.00, 95% CI: 1.04-8.65; p = 0.042), and being divorced (OR: 4.28, 95% CI: 1.27-14.47; p = 0.019). Conversely, living with others (OR: 0.24, 95% CI: 0.07-0.81; p = 0.021), and reporting unchanged stress levels (OR: 0.22, 95% CI: 0.08-0.65; p = 0.006) were associated with a lower risk of LBP worsening.

CONCLUSION

Our findings highlight key factors to consider for improving remote workers' physical and mental wellbeing and decrease their LBP burden.

Is Gender an Antecedent to Workplace Stressors? A Systematic Review and an Empirical Study Using a Person-Centred Approach

OBJECTIVE

Work is a key domain of life in which gender inequality can manifest, yet gender is rarely the explicit focus of research seeking to understand exposure to stressors. We investigated this research gap in two studies.

METHODS

Study 1 was a systematic review of the relationship between gender and key stressors (e.g., high demands, poor support, lack of clarity and control). From a total of 13,376,130 papers met our inclusion criteria. Study 2 was a cross-sectional study that included 11,289 employees nested within 71 public organisations (50.6% men). Through a latent profile analysis, we investigated the profiles of stressors separately from men and women.

RESULTS

The systematic review revealed that, for all stressors, a significant proportion of studies found no significant gender differences, and the review found mixed evidence of greater exposure for both men and women. The results of Study 2 revealed that both genders could be optimally represented by three psychosocial risk profiles reflecting medium, low and high stressors. The results also showed that while the shape of profiles was similar for both genders, men had a higher probability than women of being in the virtuous (i.e., low stressors) profile, and the opposite pattern emerged for the average profile (i.e., medium levels of stressors). Men and women displayed the same likelihood of being classified in the at-risk profile (i.e., high levels of stressors).

CONCLUSION

Gender differences in exposure to stressors are inconsistent. Although the literature on gender role theory and the gendering of work suggests different exposures to stressors in men and women, we find little empirical support for this.

Psychosocial Risks in the Changing World of Work: Moving from the Risk Assessment Culture to the Management of Opportunities

Increased attention to psychosocial risks and their potential impacts on workers' mental and physical health has flourished due to the changes taking place in the world of work. The changes in the world of work and the recent worldwide events have exacerbated the existing psychosocial risks and brought out new psychosocial risks to be considered for protecting workers' health. This favors the opening up of national and international debate on prioritizing psychosocial risks at work at the policies, strategies, and actions level. This contribution highlights the critical issues to be addressed, the needs to be covered, and the opportunities for better and more effective OSH protection in the workplace. Starting from a definition of psychosocial risks and their potential impacts, we offer an overview of the most recent developments in policies and strategies and the contribution of research in this field over time. A critical reflection on emerging topics, main needs, and challenges for organizations and stakeholders is offered. This time of change poses great concerns but also offers a great opportunity of moving from a culture of assessment to a culture of psychosocial risk management for improving workers' well-being, productivity, and health, where the risk assessment is an important step but not a point of arrival.

Demand-Resource Profiles and Job Satisfaction in the Healthcare Sector: A Person-Centered Examination Using Bayesian Informative Hypothesis Testing

Work characteristics may independently and jointly affect well-being, so that whether job demands deplete or energize employees depends on the resources available in the job. However, contradictory results on their joint effects have emerged so far in the literature. We argue that these inconsistencies can be partially explained by two arguments in the contemporary literature in the field. First, most studies in the job design domain are based on classic variable-centered methodologies which, although informative, are not well suited to investigate complex patterns of interactions among multiple variables. Second, these studies have mainly focused on generic work characteristics (e.g., workload, control, support), and are lacking in occupational specificity. Thus, to overcome these limitations, in the current research we include generic and occupation-specific work characteristics and adopt a person-centered approach to (a) identify different patterns of interactions of job demands and resources in a sample of healthcare employees, and (b) determine the degree to which these patterns are associated with employee well-being. We involved a sample of 1513 Italian healthcare providers and collected data on key job demands (workload, emotional dissonance, patient demands and physical demands) and resources (control, management support and peers' support). We focused on job satisfaction as a broad indicator of well-being. Latent profile analysis revealed four profiles of job demands and resources: high strain-isolated, resourceless, resourceful and active job on the ward. The results of Bayesian informative hypothesis testing showed the highest support for the hypothesis stating that healthcare employees belonging to the active job on the ward profile (medium-high demands, high resources) were the most satisfied. Conversely, employees belonging to the high strain-isolated profile (high demands, low resources) and the resourceless profile (medium-low demands, low resources) were the least satisfied. Overall, our study confirms the key role played by job resources in determining well-being in high-risk sectors, demonstrating that job satisfaction can develop both in challenging and less demanding situations. On a practical level, mapping the complexity of the healthcare psychosocial work environment has important implications, allowing for a better assessment process of employee well-being and helping to identify the most effective and fitting interventions.

Economic change and population health: lessons learnt from an umbrella review on the Great Recession

OBJECTIVES

Worldwide, the COVID-19 pandemic triggered the sharpest economic downturn since the Great Recession. To prepare for future crises and to preserve public health, we conduct an overview of systematic reviews to examine the evidence on the effect of the Great Recession on population health.

METHODS

We searched PubMed and Scopus for systematic reviews and/or meta-analyses focusing specifically on the impact of the Great Recession on population health (eg, mental health). Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines were followed throughout this review and critical appraisal of included systematic reviews was performed using Assessing the Methodological Quality of Systematic Reviews.

RESULTS

Twenty-one studies were identified and consistently showed that the Great Recession was most risky to health, the more a country's economy was affected and the longer strict austerity policies were in place. Consequently, a deterioration of health was highest in countries that had implemented strict austerity measures (eg, Greece), but not in countries that rejected austerity measures (eg, Germany). Moreover, the impact of the Great Recession fell disproportionately on the most vulnerable groups such as people in unemployment, at risk of unemployment and those living in poverty.

CONCLUSIONS

The experiences of the last economic crisis show that it is possible to limit the consequences for health. Prioritising mental healthcare and prevention, foregoing austerity measures in the healthcare system and protecting vulnerable groups are the most important lessons learnt. Moreover, given the further aggravating social inequalities, a health in all policies approach, based on a comprehensive Health Impact Assessment, is advised.

The effect of exposure to long working hours on depression: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are developing the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury (WHO/ILO Joint Estimates), supported by a large number of individual experts. Evidence from previous reviews suggests that exposure to long working hours may cause depression. In this article, we present a systematic review and meta-analysis of parameters for estimating (if feasible) the number of deaths and disability-adjusted life years from depression that are attributable to exposure to long working hours, for the development of the WHO/ILO Joint Estimates.

OBJECTIVES

We aimed to systematically review and meta-analyse estimates of the effect of exposure to long working hours (three categories: 41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on depression (three outcomes: prevalence, incidence and mortality).

DATA SOURCES

We developed and published a protocol, applying the Navigation Guide as an organizing systematic review framework where feasible. We searched electronic academic databases for potentially relevant records from published and unpublished studies, including the WHO International Clinical Trial Registers Platform, Medline, PubMed, EMBASE, Web of Science, CISDOC and PsycInfo. We also searched grey literature databases, Internet search engines and organizational websites; hand-searched reference lists of previous systematic reviews; and consulted additional experts.

STUDY ELIGIBILITY AND CRITERIA

We included working-age (≥15 years) workers in the formal and informal economy in any WHO and/or ILO Member State but excluded children (aged <15 years) and unpaid domestic workers. We included randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of the effect of exposure to long working hours (41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on depression (prevalence, incidence and/or mortality).

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors independently screened titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. Missing data were requested from principal study authors. We combined odds ratios using random-effects meta-analysis. Two or more review authors assessed the risk of bias, quality of evidence and strength of evidence, using Navigation Guide and GRADE tools and approaches adapted to this project.

RESULTS

Twenty-two studies (all cohort studies) met the inclusion criteria, comprising a total of 109,906 participants (51,324 females) in 32 countries (as one study included multiple countries) in three WHO regions (Americas, Europe and Western Pacific). The exposure was measured using self-reports in all studies, and the outcome was assessed with a clinical diagnostic interview (four studies), interview questions about diagnosis and treatment of depression (three studies) or a validated self-administered rating scale (15 studies). The outcome was defined as incident depression in all 22 studies, with first time incident depression in 21 studies and recurrence of depression in one study. We did not identify any study on prevalence of depression or on mortality from depression. For the body of evidence for the outcome incident depression, we had serious concerns for risk of bias due to selection because of incomplete outcome data (most studies assessed depression only twice, at baseline and at a later follow-up measurement, and likely have missed cases of depression that occurred after baseline but were in remission at the time of the follow-up measurement) and due to missing information on life-time prevalence of depression before baseline measurement. Compared with working 35-40 h/week, we are uncertain about the effect on acquiring (or incidence of) depression of working 41-48 h/week (pooled odds ratio (OR) 1.05, 95% confidence interval (CI) 0.86 to 1.29, 8 studies, 49,392 participants, I² 46%, low quality of evidence); 49-54 h/week (OR 1.06, 95% CI 0.93 to 1.21, 8 studies, 49,392 participants, I² 40%, low quality of evidence); and ≥ 55 h/week (OR 1.08, 95% CI 0.94 to 1.24, 17 studies, 91,142 participants, I² 46%, low quality of evidence). Subgroup analyses found no evidence for statistically significant (P < 0.05) differences by WHO region, sex, age group and socioeconomic status. Sensitivity analyses found no statistically significant differences by outcome measurement (clinical diagnostic interview [gold standard] versus other measures) and risk of bias ("high"/"probably high" ratings in any domain versus "low"/"probably low" in all domains).

CONCLUSIONS

We judged the existing bodies of evidence from human data as "inadequate evidence for harmfulness" for all three exposure categories, 41-48, 48-54 and ≥55 h/week, for depression prevalence, incidence and mortality; the available evidence is insufficient to assess effects of the exposure. Producing estimates of the burden of depression attributable to exposure to long working appears not evidence-based at this point. Instead, studies examining the association between long working hours and risk of depression are needed that address the limitations of the current evidence.

How Much Does My Work Affect My Health? The Relationships between Working Conditions and Health in an Italian Survey

BACKROUND

Working condition surveys are widely recognized as useful tools for monitoring the quality of working life and the improvements introduced by health and safety policy frameworks at the European and national level. The Italian Workers' Compensation Authority carried out a national survey (Insula) to investigate the employer's perceptions related to working conditions and their impact on health.

METHODS

The present study is based on the data collected from the Italian survey on health and safety at work (INSULA) conducted on a representative sample of the Italian workforce (n = 8,000). This focuses on the relationship between psychosocial risk factors and self-reported health using a set of logistic and linear regression models.

RESULTS

Working conditions such as managerial support, job satisfaction, and role act as protective factors on mental and physical health. On the contrary, workers' risk perceptions related to personal exposure to occupational safety and health risks, concern about health conditions, and work-related stress risk exposure determine a poorer state of health.

CONCLUSIONS

This study highlights the link between working conditions and self-report health, and this aims to provide a contribution in the field of health at work. Findings show that working conditions must be object of specific preventive measures to improve the workers' health and well-being.

Implementing Smart Working in Public Administration: a follow up study

BACKGROUND

Starting from February 2020, in Italy most organizations have had a forced transition to flexible working practice - called "smart working in emergency" - due to the Covid-19 epidemic outbreak. This allowed to continue work activities and services and contributed to contain the risk of infection in different sectors, particularly in the public administration.

OBJECTIVES

This follow up study focussed on a panel of 187 workers from the Italian Workers' Compensation Authority taking part to a pilot project "Smart Working in INAIL" from January 2019 to December 2019. The aim was to investigate the effects of work organization on work attitudes, work-life balance and health outcomes before and after the introduction of the smart working.

METHODS

The data were collected at two time points through a web-based questionnaire. The first wave aimed to collect information up to one month before the implementation of the smart working. The second wave aimed to collect information about potential changes occurred after one year of smart working.

RESULTS

This study showed that high demands, low control and low social support might lead to reduced well-being and less satisfaction with work, and have an effect on work engagement and work-life balance. Particularly, improving social support can moderate the negative impact of high strain on well-being, preventing work-life imbalance and risk of isolation.

DISCUSSION

Findings and future perspectives are discussed to support stakeholders in defining policies and practices concerning health and wellbeing at work while preserving productivity, for a successful implementation of smart working in the public administration.

The Role of Occupational Health Services in Psychosocial Risk Management and the Promotion of Mental Health and Well-Being at Work

The development and enhancement of occupational health services (OHS) at the national level is central to ensuring the sustainable health, well-being and work engagement of the working population. However, due to differences in national health, social security and occupational safety and health systems, the content, capacity, coverage and provisions of OHS vary considerably across national contexts. Obtaining a better understanding in terms of such similarities and variations internationally is essential as such comparative information can help inform evidenced-based decision-making on OHS at both policy and practice levels. This paper therefore reviews and analyses the key policies, standards and approaches in OH systems and services, using both academic and grey literature, across 12 industrialised countries (Australia, Canada, Finland, France, Germany, Ireland, Italy, Japan, The Netherlands, Poland, United Kingdom and the United States of America). It provides a detailed overview and categorization of OHS in these selected countries in terms of the legal and policy context, organisation and financing and coverage and staffing while specifically discussing variations aimed at psychosocial risk management and the promotion of mental health and well-being at work. It draws conclusions on key development needs of OHS internationally to ensure psychosocial risk management and mental health promotion are prioritised effectively in a preventive manner.

Developing a cost-estimation model for work-related stress: An absence-based estimation using data from two Italian case studies

Objectives:

This paper discusses the development of a cost-estimation model for work-related stress based on psychosocial risk exposure and absence from work. It presents findings from its implementation and evaluation in two organizations in Italy, using national-level tools developed by the Italian Workers’ Compensation Authority (INAIL). It also provides recommendations for the development of similar cost-calculation methods in other countries.

Methods:

The cost-estimation model was based on the human capital approach using an indirect cost indicator: loss of productivity due to days of absence attributable to work-related stress. Furthermore, the population attributable fraction (PAF) epidemiological measure was used to calculate the impact of exposure to work-related stress on the basis of data collected through validated tools developed by INAIL and salary cost data.

Results:

The developed model was implemented and evaluated in two organizations, the first in healthcare (N=1014) and the second in public administration (N=534). In the first case, it was found that absence related to work-related stress cost the organization €445 000. In the second case, the cost was €360 000.

Conclusions:

The proposed model provides an example of how organizations can incorporate well-established indicators associated with work-related stress (eg, various types of absence, psychosocial risk perception, loss of productivity on the basis of salary costs) in a practical way in cost estimations of work-related stress. Such cost estimation can be applied in other countries and organizations to establish the economic and business case of managing work-related stress.

The management of psychosocial risks at work: state of the art and future perspectives

BACKGROUND

Psychosocial risk management represents a current challenge in Occupational Health and Safety (OSH) due to their impacts of such risks on work stress and the rapid changes of the world of work. An effective psychosocial risk management can be carried out on the basis of an integrated multidisciplinary model founded on the risk management paradigm. Over years, the occupational medicine has played an important role at national level in this area, contributing to the creation of an integrated and participatory approach.

OBJECTIVES

This study explores the developmental process of psychosocial risk management over time in Europe and Italy, to offer an update on the state of the art at a national level and insights on future perspectives.

METHODS

Through a reflection on research developments, in Europe and in Italy, we outline how the knowledge obtained has been translated into policies, which have encouraged the implementation at international and national level of consolidated practices for the management of psychosocial risks.

RESULTS

An overview of some key steps of the inclusion of psychosocial aspects in OSH is presented, highlighting the positive impact of the multidisciplinary approach. Moreover, the driving role played by policies for implementation in organizational practice is also highlighted, with particular reference to the Italian example.

DISCUSSION

Starting from the existing knowledge, it is necessary to tackle emerging risks by continuing to translate the knowledge obtained from research into policies that have a driving role in the identification and implementation of actions and practical tools.

The effect of exposure to long working hours on stroke: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are developing joint estimates of the work-related burden of disease and injury (WHO/ILO Joint Estimates), with contributions from a large network of individual experts. Evidence from mechanistic data and prior studies suggests that exposure to long working hours may cause stroke. In this paper, we present a systematic review and meta-analysis of parameters for estimating the number of deaths and disability-adjusted life years from stroke that are attributable to exposure to long working hours, for the development of the WHO/ILO Joint Estimates.

OBJECTIVES

We aimed to systematically review and meta-analyse estimates of the effect of exposure to long working hours (three categories: 41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on stroke (three outcomes: prevalence, incidence, and mortality).

DATA SOURCES

A protocol was developed and published, applying the Navigation Guide to systematic reviews as an organizing framework where feasible. We searched electronic databases for potentially relevant records from published and unpublished studies, including Ovid MEDLINE, PubMed, EMBASE, Scopus, Web of Science, CISDOC, PsycINFO, and WHO ICTRP. We also searched grey literature databases, Internet search engines, and organizational websites; hand-searched reference lists of previous systematic reviews; and consulted additional experts.

STUDY ELIGIBILITY AND CRITERIA

We included working-age (≥15 years) individuals in the formal and informal economy in any WHO and/or ILO Member State but excluded children (aged < 15 years) and unpaid domestic workers. We included randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of the effect of exposure to long working hours (41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on stroke (prevalence, incidence or mortality).

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors independently screened titles and abstracts against the eligibility criteria at a first review stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. Missing data were requested from principal study authors. We combined relative risks using random-effects meta-analysis. Two or more review authors assessed the risk of bias, quality of evidence and strength of evidence, using the Navigation Guide and GRADE tools and approaches adapted to this project.

RESULTS

Twenty-two studies (20 cohort studies, 2 case-control studies) met the inclusion criteria, comprising a total of 839,680 participants (364,616 females) in eight countries from three WHO regions (Americas, Europe, and Western Pacific). The exposure was measured using self-reports in all studies, and the outcome was assessed with administrative health records (13 studies), self-reported physician diagnosis (7 studies), direct diagnosis by a physician (1 study) or during a medical interview (1 study). The outcome was defined as an incident non-fatal stroke event in nine studies (7 cohort studies, 2 case-control studies), incident fatal stroke event in one cohort study and incident non-fatal or fatal ("mixed") event in 12 studies (all cohort studies). Cohort studies were judged to have a relatively low risk of bias; therefore, we prioritized evidence from these studies, but synthesised evidence from case-control studies as supporting evidence. For the bodies of evidence for both outcomes with any eligible studies (i.e. stroke incidence and mortality), we did not have serious concerns for risk of bias (at least for the cohort studies). Eligible studies were found on the effects of long working hours on stroke incidence and mortality, but not prevalence. Compared with working 35-40 h/week, we were uncertain about the effect on incidence of stroke due to working 41-48 h/week (relative risk (RR) 1.04, 95% confidence interval (CI) 0.94-1.14, 18 studies, 277,202 participants, I² 0%, low quality of evidence). There may have been an increased risk for acquiring stroke when working 49-54 h/week compared with 35-40 h/week (RR 1.13, 95% CI 1.00-1.28, 17 studies, 275,181participants, I² 0%, p 0.04, moderate quality of evidence). Compared with working 35-40 h/week, working ≥55 h/week may have led to a moderate, clinically meaningful increase in the risk of acquiring stroke, when followed up between one year and 20 years (RR 1.35, 95% CI 1.13 to 1.61, 7 studies, 162,644 participants, I² 3%, moderate quality of evidence). Compared with working 35-40 h/week, we were very uncertain about the effect on dying (mortality) of stroke due to working 41-48 h/week (RR 1.01, 95% CI 0.91-1.12, 12 studies, 265,937 participants, I² 0%, low quality of evidence), 49-54 h/week (RR 1.13, 95% CI 0.99-1.29, 11 studies, 256,129 participants, I² 0%, low quality of evidence) and 55 h/week (RR 1.08, 95% CI 0.89-1.31, 10 studies, 664,647 participants, I² 20%, low quality of evidence). Subgroup analyses found no evidence for differences by WHO region, age, sex, socioeconomic status and type of stroke. Sensitivity analyses found no differences by outcome definition (exclusively non-fatal or fatal versus "mixed") except for the comparison working ≥55 h/week versus 35-40 h/week for stroke incidence (p for subgroup differences: 0.05), risk of bias ("high"/"probably high" ratings in any domain versus "low"/"probably low" in all domains), effect estimate measures (risk versus hazard versus odds ratios) and comparator (exact versus approximate definition).

CONCLUSIONS

We judged the existing bodies of evidence for human evidence as "inadequate evidence for harmfulness" for all exposure categories for stroke prevalence and mortality and for exposure to 41-48 h/week for stroke incidence. Evidence on exposure to 48-54 h/week and ≥55 h/week was judged as "limited evidence for harmfulness" and "sufficient evidence for harmfulness" for stroke incidence, respectively. Producing estimates for the burden of stroke attributable to exposures to working 48-54 and ≥55 h/week appears evidence-based, and the pooled effect estimates presented in this systematic review could be used as input data for the WHO/ILO Joint Estimates. PROTOCOL IDENTIFIER: https://doi.org/10.1016/j.envint.2018.06.016.

PROSPERO REGISTRATION NUMBER

CRD42017060124.

Precarious employment and self-reported experiences of unwanted sexual attention and sexual harassment at work. An analysis of the European Working Conditions Survey

Unwanted sexual attention (UWSA) and sexual harassment (SH) are prevalent experiences for women in working life and often accompanied by poor health. Despite increasing numbers especially of young people working in insecure and irregular employment settings, there is little empirical evidence if such precarious arrangements are associated with UWSA or SH. To investigate this, we used a representative sample of the European working population consisting of 63,966 employees in 33 countries who participated in the European Working Conditions Survey in 2010 or 2015. Precarious employment (PE) was assessed on the basis of seven indicators and a formative index derived from them: temporary employment, contractual duration < 1 year, schedule unpredictability, involuntary part-time, low information on occupational health and safety risks (OSH), low pay (wage < 60%), and multiple job-holding. We measured self-reported experiences of workplace UWSA during the last month and SH during the last 12 months each using a single-item questionnaire. Multi-level Poisson regressions were used to estimate prevalence ratios for UWSA and SH according to PE adjusted for survey year, age, education, type of household, migration background, job tenure, weekly working hours, occupational position, working sector, company size, workplace gender ratio, and visiting customers or clients. 0.8% of men reported UWSA in the last month and 2.6% of the women. SH in the last year was reported by 0.4% of the men and 1.3% of the women. For both men and women, PE was significantly associated with elevated prevalence of UWSA and SH, in particular when reporting schedule unpredictability, multiple job-holding and low information on OSH. Our results suggest that precariously employed individuals may be more prone to experience unwanted sexual behaviour at the workplace compared with workers in non-precarious settings.

Improving Working Conditions and Job Satisfaction in Healthcare: A Study Concept Design on a Participatory Organizational Level Intervention in Psychosocial Risks Management

This paper contributes to the literature on organizational interventions on occupational health by presenting a concept study design to test the efficacy of a Participatory Organizational-level Intervention to improve working conditions and job satisfaction in Healthcare. The Participatory Organizational-level Intervention is developed using the Italian methodology to assess and manage psychosocial risks tailored to Healthcare. We added an additional step: evaluation, aiming to examine how the intervention works, what worked for whom and in which circumstances. This ongoing study is conducted in collaboration with two large Italian hospitals (more than 7000 employees). The study design comprises a quasi-experimental approach consisting of five phases and surveys distributed pre- and post-intervention aiming to capture improvements in working conditions and job satisfaction. Moreover, to evaluate the efficacy of the Intervention in terms of process and content, we use a realist evaluation to test Context-Mechanisms-Outcome (CMO) configurations. We collect contextual factors at baseline and during and post-intervention process data on the key principles of line manager support and employees participation. This study is expected to provide insights on methods and strategies to improve working conditions and employees’ job satisfaction and on national policies in the occupational health framework.

Assessing the Risk of Stress in Organizations: Getting the Measure of Organizational-Level Stressors

Great Britain's Health and Safety Executive (HSE) developed the Management Standards Indicator Tool to help organizations to assess and monitor organizational risks of work-related stress through surveying employees about the psychosocial risks for stress in their jobs. The use of employee-level data for deriving an organizational-level measure of psychosocial risks assumes that the constructs have equivalent meanings at different levels. However, this isomorphic condition has never been tested and this study fills this gap. Using data collected by the Italian Workers' Compensation Authority (INAIL) from 66,188 employees nested in 775 organizations, we demonstrate that the organizational-level measure representing the seven dimensions of the Management Standards Indicator Tool is equivalent, though not identical, to the individual-level measure. This implies that the organizational level is not a mirror of the aggregation of the individual level, and that the risk of work-related stress in an organization may derive not simply from bottom-up processes, but may be generated by top-down influences (e.g., organizational policies). Interventions may then be meaningfully targeted at the organizational level in the expectation that they will reduce the risk of work-related stress among the entire workforce, the valid measurement of which can be performed through the HSE's Management Standards Indicator Tool.

Do Temporary Workers More Often Decide to Work While Sick? Evidence for the Link between Employment Contract and Presenteeism in Europe

European employees are increasingly likely to work in cases of illness (sickness presenteeism, SP). Past studies found inconsistent evidence for the assumption that temporary workers decide to avoid taking sick leave due to job insecurity. A new measure to identify decision-based determinants of SP is presenteeism propensity (PP), which is the number of days worked while ill in relation to the sum of days worked while ill and days taken sickness absence. We investigated the link between employment contract and PP using cross-sectional data from 20,240 employees participating in the 2015 European Working Conditions Survey. Workers were grouped by type and duration of employment contract. The link between contract and PP was estimated using a multilevel Poisson model adjusted for socio-demographical, occupational and health-related covariates. We found that European employees worked 39% of the days they were ill. In contrast to previous studies, temporary workers were significantly more likely to decide for presenteeism than permanent workers were, especially when the contract was limited to less than 1 year. Controlling for perceived job insecurity did just marginally attenuate this association. Presenteeism was also more common among young and middle-aged workers; however, we did not find a significant interaction between contract and age affecting presenteeism. In conclusion, the employment contract is an important determinant of presenteeism. Our results give reason to believe that temporary workers show increased attendance behavior independent of job insecurity, because they are less likely to have access to social protection in case of illness.

WHO/ILO work-related burden of disease and injury: Protocol for systematic reviews of exposure to long working hours and of the effect of exposure to long working hours on depression

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are developing a joint methodology for estimating the national and global work-related burden of disease and injury (WHO/ILO joint methodology), with contributions from a large network of experts. In this paper, we present the protocol for two systematic reviews of parameters for estimating the number of deaths and disability-adjusted life years from depression attributable to exposure to long working hours, to inform the development of the WHO/ILO joint methodology.

OBJECTIVES

We aim to systematically review studies on occupational exposure to long working hours (Systematic Review 1) and systematically review and meta-analyse estimates of the effect of long working hours on depression (Systematic Review 2), applying the Navigation Guide systematic review methodology as an organizing framework, conducting both systematic reviews in tandem and in a harmonized way.

DATA SOURCES

Separately for Systematic Reviews 1 and 2, we will search electronic academic databases for potentially relevant records from published and unpublished studies, including Medline, EMBASE, Web of Science, CISDOC and PsycINFO. We will also search electronic grey literature databases, Internet search engines and organizational websites; hand search reference list of previous systematic reviews and included study records; and consult additional experts.

STUDY ELIGIBILITY AND CRITERIA

We will include working-age (≥15 years) participants in the formal and informal economy in any WHO and/or ILO Member State, but exclude child workers (<15 years) and unpaid domestic workers. For Systematic Review 1, we will include quantitative prevalence studies of relevant levels of occupational exposure to long working hours (i.e. 35-40, 41-48, 49-54 and ≥55 h/week) stratified by country, sex, age and industrial sector or occupation, in the years 2005-2018. For Systematic Review 2, we will include randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of the relative effect of relevant level(s) of long working hours on the incidence of or mortality due to depression, compared with the theoretical minimum risk exposure level (i.e. 35-40 h/week).

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors will independently screen titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. At least two review authors will assess risk of bias and the quality of evidence, using the most suited tools currently available. For Systematic Review 2, if feasible, we will combine relative risks using meta-analysis. We will report results using the guidelines for accurate and transparent health estimates reporting (GATHER) for Systematic Review 1 and the preferred reporting items for systematic reviews and meta-analyses guidelines (PRISMA) for Systematic Review 2.

PROSPERO REGISTRATION NUMBER

CRD42018085729.

Assessing Objective and Verifiable Indicators Associated With Work-Related Stress: Validation of a Structured Checklist for the Assessment and Management of Work-Related Stress

Risk assessment represents an essential part of any successful intervention in health and safety at work. The most prominent European methodologies propose multi-method approaches for identifying the risks associated with work-related stress. Nevertheless, the most widely used method is the self-administered questionnaire. By adapting the UK Management Standards approach, the Italian National Workers Compensation Authority (INAIL) developed a checklist for the assessment of objective and verifiable indicators of work-related stress. This checklist is filled in by a steering group composed of homogenous groups of workers. Through a web-platform developed by INAIL, a considerable amount of data over the last 5 years has been collected throughout Italy. The aims of this study are to examine the psychometric properties as well as the practical validity of the checklist in a wide sample of Italian companies. The sample comprised 5,301 homogeneous groups of workers nested within 1,631 organizations. The checklist measures two main areas: (1) the organizational indicators of work-related stress (sentinel events) and (2) four and six factors related respectively to content and context of work. Multilevel and multivariate analyses revealed that the checklist shows adequate factor structure and criterion validity. Results also demonstrate that small companies and the public and healthcare sector show higher risk levels. These results support the use of the checklist as a structured and generalizable tool for assessing and monitoring the risks associated with work-related stress.

WHO/ILO work-related burden of disease and injury: Protocol for systematic reviews of exposure to long working hours and of the effect of exposure to long working hours on stroke

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are developing a joint methodology for estimating the national and global work-related burden of disease and injury (WHO/ILO joint methodology), with contributions from a large network of experts. In this paper, we present the protocol for two systematic reviews of parameters for estimating the number of deaths and disability-adjusted life years from stroke attributable to exposure to long working hours, to inform the development of the WHO/ILO joint methodology.

OBJECTIVES

We aim to systematically review studies on occupational exposure to long working hours (called Systematic Review 1 in the protocol) and systematically review and meta-analyse estimates of the effect of long working hours on stroke (called Systematic Review 2), applying the Navigation Guide systematic review methodology as an organizing framework, conducting both systematic reviews in tandem and in a harmonized way.

DATA SOURCES

Separately for Systematic Reviews 1 and 2, we will search electronic academic databases for potentially relevant records from published and unpublished studies, including Medline, EMBASE, Web of Science, CISDOC and PsychINFO. We will also search electronic grey literature databases, Internet search engines and organizational websites; hand-search reference list of previous systematic reviews and included study records; and consult additional experts.

STUDY ELIGIBILITY AND CRITERIA

We will include working-age (≥15 years) workers in the formal and informal economy in any WHO and/or ILO Member State, but exclude children (<15 years) and unpaid domestic workers. For Systematic Review 1, we will include quantitative prevalence studies of relevant levels of occupational exposure to long working hours (i.e. 35-40, 41-48, 49-54 and ≥55 h/week) stratified by country, sex, age and industrial sector or occupation, in the years 2005-2018. For Systematic Review 2, we will include randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of the relative effect of a relevant level of long working hours on the incidence of or mortality due to stroke, compared with the theoretical minimum risk exposure level (i.e. 35-40 h/week).

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors will independently screen titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. At least two review authors will assess risk of bias and the quality of evidence, using the most suited tools currently available. For Systematic Review 2, if feasible, we will combine relative risks using meta-analysis. We will report results using the guidelines for accurate and transparent health estimates reporting (GATHER) for Systematic Review 1 and the preferred reporting items for systematic reviews and meta-analyses guidelines (PRISMA) for Systematic Review 2. PROSPERO registration number: CRD42017060124.

What makes employees engaged with their work? The role of self-efficacy and employee’s perceptions of social context over time

Purpose

– Work engagement represents an important aspect of employee well-being and performance and has been related to both job and personal resources. The purpose of this paper, based on Social Cognitive Theory, is to emphasize the proactive role of self-efficacy which is hypothesized to predict work engagement, not only directly, but also indirectly through positive changes in employee’s perceptions of social context (PoSC); namely, perceptions of one’s immediate supervisor, colleagues and top management.

Design/methodology/approach

– A sample of 741 employees of a communication service company completed two questionnaires, with a time interval of three years. Structural equation modeling was performed in order to test the hypothesized model.

Findings

– Results revealed that, as expected: first, initial self-efficacy predicts work engagement three years later; and second, positive changes in employee’s perceptions of the social work context across the three year period, mediates the relationship between self-efficacy and work engagement.

Research limitations/implications

– Results relied only upon self-report data. Moreover, each variable was only measured at the time in which it was hypothesized by the conceptual model.

Practical implications

– The significant role of self-efficacy as a direct and indirect predictor of work engagement suggests the development of training programs centered on the main sources of self-efficacy, specifically focussed on the social work domain.

Originality/value

– This research provides evidence of the substantial contribution of self-efficacy to work engagement over time. Moreover, the results also support the beneficial effects of self-efficacy through its influence on the improvements in the individuals’ perceptions of their social context.

Do Italian Companies Manage Work-Related Stress Effectively? A Process Evaluation in Implementing the INAIL Methodology

Studies on Intervention Process Evaluation are attracting growing attention in the literature on interventions linked to stress and the wellbeing of workers. There is evidence that some elements relating to the process and content of an intervention may have a decisive role in implementing it by facilitating or hindering the effectiveness of the results. This study aimed to provide a process evaluation on interventions to assess and manage risks related to work-related stress using a methodological path offered by INAIL. The final sample is composed of 124 companies participating to an interview on aspects relating to each phase of the INAIL methodological path put in place to implement the intervention. INAIL methodology has been defined as useful in the process of assessing and managing the risks related to work-related stress. Some factors related to the process (e.g., implementation of a preliminary phase, workers' involvement, and use of external consultants) showed a role in significant differences that emerged in the levels of risk, particularly in relation to findings from the preliminary assessment. Main findings provide information on the key aspects of process and content that are useful in implementing an intervention for assessing and managing risks related to work-related stress.

Temporary Workers’ Satisfaction

Workers exposed to job insecurity and job changes are ever increasing, however, studies among temporary workers are underrepresented in the literature. This study adopts a positive approach to the topic investigating the individual factors leading temporary workers to take advantage from their flexible jobs. This study, carried on among 471 temporary workers, hypothesized that self-efficacy and internal locus of control are associated with work satisfaction and with the perception of situational opportunities. Moreover, self-efficacy is posited to indirectly relate to work satisfaction through the perception of situational opportunities and career enhancement strategies. Findings attested a direct association between internal locus of control and satisfaction and an indirect association between self-efficacy and work satisfaction.

[The INSuLa Project: a knowledge survey of employers]

In the framework of the INSuLa project, supported by Italian Ministry of Health, a national survey was conducted to evaluate the perceptions of employers about Occupational Safety and Health (OSH) activities. Main findings of this survey are presented in this paper. The survey was conducted on a sample of 1,010 employers weighted by economic activity sector, company size and geographic area. An ad hoc questionnaire was administered through Computer Assisted Telephone Interviewing methodology. Most of employers "mostly" or "completely" agree with the usefulness of OSH activities and the efficacy of specific prevention and protection measures. Around 37.7% of employers consider OSH management a shared responsibility with workers and 56.1% of them feel the OSH level to be increased following the implementation of Legislative Decree no. 81/08. The findings of this survey provide a picture of Italian employers' point of view about OSH and identify gaps and needs, thus contributing to choose proper actions for the improvement of OSH

Self efficacy, perceptions of social context, job satisfaction and their relationship with absence from work. An integrated model founded on social cognitive theory

BACKGROUND

Absenteeism is a major concern for organizations and companies since it has negative repercussions on productivity and represents a huge cost due to sick pay and expensive temporary replacement of employees who are obliged to take long-term absences.

OBJECTIVES

The current study aimed at focussing on absenteeism and its causes through the investigation of a conceptual model founded on social cognitive theory where self-efficacy and Perceptions of Social Context (PoSC, i.e., perceptions of immediate supervisor, colleagues and top management) concur to predict absence from work through the mediating role of job satisfaction.

METHODS

A group of 361 sales assistants and administrative staff employed by the Italian branch of a retail clothing multinational were administered a self-report questionnaire for measuring self-efficacy, PoSC and job satisfaction. We then matched the self-report answers with objective absence measures.

RESULTS

Structural equation modelling lent support to the presumed relationships between variables. We found that: 1) self-efficacy was positively related to the three PoSC; 2) PoSC had a positive relationship with job satisfaction; 3) job satisfaction was negatively related to absence from work; 4) job satisfaction mediated the relationship between PoSC and absence from work.

CONCLUSIONS

Overall, our contribution offers a theoretical basis for further investigations on the role of individual characteristics and perceptions of social context in absenteeism studies via both observational and intervention studies and cost-effectiveness analysis.

The relevance of socio-demographic and occupational variables for the assessment of work-related stress risk

BACKGROUND

Work-related stress is widely recognized as one of the major challenges to occupational health and safety. The correlation between work-related stress risk factors and physical health outcomes is widely acknowledged. This study investigated socio-demographic and occupational variables involved in perceived risk of work-related stress.

METHODS

The Italian version of the Health and Safety Executive Management Standards Indicator Tool was used in a large survey to examine the relationship between work-related stress risks and workers' demographic and occupational characteristics. Out of 8,527 questionnaires distributed among workers (from 75 organizations) 6,378 were returned compiled (74.8%); a set of mixed effects models were adopted to test single and combined effects of the variables on work-related stress risk.

RESULTS

Female workers reported lower scores on control and peer support and more negative perceptions of relationships and change at work than male workers, most of them with full-time contracts. Age, job seniority, and educational level appeared positively correlated with control at work, but negatively with job demands. Fixed-term workers had positive perceptions regarding job demands and relationships, but more difficulties about their role at work than permanent workers. A commuting time longer than one hour and shift work appeared to be associated with higher levels of risk factors for work-related stress (except for role), the latter having more negative effects, increasing with age.

CONCLUSIONS

The findings suggest that the assessment and management of work-related stress risk should consider specific socio-demographic and occupational risk factors such as gender, age, educational level, job status, shift work, commuting time, job contracts.