Exploring expected and perceived facilitators and barriers of an indicated prevention strategy to prevent future long-term sickness absence; a qualitative study among employers and employees.

BACKGROUND: An indicated prevention strategy (IPS), consisting of a screening questionnaire and early treatment, was found to be effective for the prevention of future long-term sickness absence (LTSA) in two large Dutch RCT's. This IPS aims to detect employees who have a high risk to become absent, and subsequently offer them early treatment. Despite the overall effectiveness, only a few companies have implemented this strategy so far. This suggests that companies may not be convinced of the (cost) effectiveness of this strategy yet. In companies where IPS has been implemented, screenings uptake and adherence to early treatment appeared to be moderate, indicating that both employees and employers might perceive barriers. METHODS: The aim of this qualitative study was to explore the expected and perceived facilitators and barriers for the implementation of the IPS. Semi-structured interviews were conducted with 9 employers and 11 employees (acquainted and unacquainted with IPS) from large companies. Purposive sampling was used to recruit participants. All interviews were transcribed and analyzed thematically. RESULTS: The employers believed they were primarily responsible for psychological and work-related health complaints and SA, while the employees felt responsible for health complaints related to their lifestyle. According to the employees, the responsibility of the employer was solely related to work-related health. This finding exposed a relation with the health culture, which was solely based on creating a safe work environment, omitting psychological health issues. The efficacy of this IPS regarding reducing SA was estimated positive, however, the efficacy regarding LTSA was questioned. Fear of a privacy breach was often mentioned by the respondents as an important barrier. CONCLUSIONS: This study showed that the health culture within a company may be important for the perceived responsibility towards SA and health. A health culture which primarily focuses on physical complaints may raise barriers for the adoption and implementation of this preventive strategy. Participant' perceptions of the nature of LTSA and the fact that not all participants were familiar with the exact content and phasing of IPS may have doubted the efficacy regarding LTSA. This study provides important clues for future and improved implementation of IPS.

The course of complaints of arm, neck and/or shoulder: a cohort study in a university population participating in work or study.

BACKGROUND: Not much is known about the characteristics, course and prognosis of complaints of arm, neck and/or shoulder that have not been caused by a trauma or systemic disease (CANS), in a screened population. This study aims to: (1) describe personal and complaint characteristics in a screened population; (2) describe the course during one-year follow-up, in terms of the three different domains of functioning of the International Classification of Functioning, Disability and Health (ICF); and (3) to explore prognostic factors for the different domains of functioning at one-year follow-up. Additionally, this study aims to investigate the manifestation of selection effects (i.e. tertiary selection effects), in order to understand their impact on the interpretation of results. METHODS: A cross-sectional survey was conducted in a university population. Survey respondents who fulfilled eligibility criteria were asked to participate in a longitudinal cohort study. The course of CANS was assessed in terms of the three ICF domains of functioning. Possible prognostic factors across the different components of the ICF were selected to investigate their influence on outcome at one-year follow-up. Non-response analyses were performed to investigate the presence of tertiary selection effects. RESULTS: The results revealed a population with relatively mild complaints at baseline, and a relatively stable course during follow-up. Because of the small change in scores between baseline and follow-up measurements, examination of prognostic factors was not feasible. The results of the non-response analyses revealed some indications for the potential presence of tertiary selection effects, which may imply that the results obtained are a slight overestimation of the true results. CONCLUSION: The results of this study demonstrate mild complaints at baseline and an overall stable course during one-year follow-up. Since selection effects cannot be ruled out, the true course might possibly be somewhat less favourable than our results suggest.

The impact of work-related and personal resources on older workers' fatigue, work enjoyment and retirement intentions over time.

This study aims to examine the impact of work-related and personal resources on older workers' retirement intentions by studying the pathways (fatigue and work enjoyment) from resources to retirement intentions, the buffering role of resources for psychological job demands, in a cross-sectional and longitudinal timeframe. Longitudinal results on a subsample of full-time, older workers (n = 1642) from the Maastricht Cohort Study suggest that over four years of follow-up personal resources like personal mastery and perceived health related to less (prolonged) fatigue and more work enjoyment. Personal mastery also related to later retirement intentions. A work-related resource like decision authority related to less prolonged fatigue. (Prolonged) fatigue related to earlier retirement intentions, suggesting that fatigue may be a pathway to early retirement. Finally, little evidence was found for effect modification by resources. This prospective study indicates that work-related and personal resources may be useful for prolonging working careers. Practitioner Summary: To date, the impact of work-related and personal resources on older workers' retirement intentions is rarely studied. As this prospective study shows that resources may impact older workers' (prolonged) fatigue, work enjoyment and retirement intentions, the monitoring and fostering of resources is of importance for prolonging their working careers.

Towards a preventive strategy for complaints of arm, neck and/or shoulder (CANS): the role of help seeking behaviour.

BACKGROUND: When developing an effective early preventive strategy for employees and students with CANS (Complaints of Arm, Neck or Shoulder, not caused by acute trauma or systemic disease), insight in help seeking behaviour and knowledge of factors associated with help seeking behaviour within the target population, is a prerequisite. The aim of this study was to examine whether perceived hindrance is associated with help seeking behaviour, specifically in employees and students identified with CANS. Additionally, the associations of factors related to functioning and participation, work-environment and demographics with help seeking behaviour were explored in these groups. METHODS: A cross-sectional survey was conducted among employees and students of two universities in the South of the Netherlands. The questionnaire included questions to assess (1) demographics, work/study and activity related factors (2) experience of CANS (3) perceived hindrance (4) help seeking behaviour. A subpopulation of the survey, consisting of those employees and students with self-reported CANS, received additional questionnaires to examine the impact of (1) participant characteristics (2) complaint and health related variables (3) functioning and participation (4) work-environment and social support, on help seeking behaviour. RESULTS: 37.3% of the employees and 41.4% of the students reported CANS. Of these, respectively 43.3% and 45.5%, did not seek help and had no intention to seek help either. Employees and students who had not sought help reported less hindrance, less perceived disabilities and shorter duration of complaints, compared those who did seek help. Employees and students within this group who had also no intention to seek help, perceived fewer disabilities and reported shorter duration of complaints. CONCLUSION: The absence of help seeking behaviour in respondents with CANS is a bottleneck for implementation of preventive strategies. In employees and students with CANS, help seeking behaviour is primarily determined by factors related to experienced hindrance. Our findings emphasize the need to tailor preventive strategies, in order to optimize screening and participation in early interventions for CANS.

Chronic conditions and self-perceived health among older employees in relation to indicators of labour participation and retirement over time.

BACKGROUND: A significant proportion of older employees leave the labour market early, amongst others via unemployment or disability benefits, implying that health might affect possibilities to extend working life. OBJECTIVE: This study 1) examined associations between chronic conditions (subtypes) and self-perceived health (SPH), independently, and indicators of labour participation and retirement over six-year follow-up among older employees, and 2) explored the impact of differences between prevalent and incident presence of chronic condition(s) in this relation. METHODS: Older workers (aged > 45 years) included in the Maastricht Cohort Study were studied (n = 1,763). The Health and Work Performance Questionnaire assessed chronic conditions and one item from the Short Form health survey-36 assessed SPH. Cox regression analyses assessed associations between chronic conditions and SPH, independently, and retirement intentions, employment status, decreasing working hours, and changes in work over time. RESULTS: Employees with coexistent physical-mental chronic conditions showed higher risks to lose employment and to receive a disability benefit (HR 1.85, 95% CI 1.23-2.78; HR 8.63, 95% CI 2.47-30.11) over time compared to healthy employees. No statistically significant associations were found between SPH and indicators of labour participation and retirement over time. Having chronic condition(s) was cross-sectionally associated with lower SPH scores and larger proportion of part-timers -compared to healthy employees. CONCLUSIONS: Chronic condition(s) among older employees were substantially associated with indicators of labour participation and retirement over time. The role of SPH was mainly instantaneous. Findings provide valuable input for preventive measures aiming to prevent an early labour market exit of older employees.

Prevention of long-term sickness absence and major depression in high-risk employees: a randomised controlled trial.

OBJECTIVES: To examine the efficacy of early intervention on the prevention of long-term sickness absence and major depression among employees at high risk of future sickness absence and with mild to severe depressive complaints. METHODS: Randomised controlled trial conducted among employees working in an office environment. 139 employees were identified both at high risk of future sickness absence and with mild to severe depressive complaints through screening. Subsequently, they were randomly assigned to the intervention group (n = 69) or the control group (n = 70). Objective sickness absence was analysed at 12 and 18 months of follow-up. Depressive complaints were assessed by the Beck Depression Inventory (BDI-II) at baseline, and at 6 and 12 months of follow-up. RESULTS: Intention-to-treat analyses showed a significant difference in total sickness absence duration between the intervention (27.5 calendar days (SD 44.7)) and control group (50.8 days (SD 75.8)) over 12 months of follow-up, a reduction of 46% (p = 0.017). The intervention group showed a non-significantly lower proportion of long-term sickness absence spells compared with the control group (p = 0.127). Statistically significant and clinically relevant differences in depressive complaints were found after both 6 months (p = 0.001) and 12 months (p = 0.005) of follow-up, in favour of the intervention group. Relative risk reductions (RRR) were 19.2% and 19.8% respectively. Sickness absence data were available for all participants over 18 months of follow-up. Questionnaire data were available for 99 (at 6 months) and 90 participants (at 12 months). No adverse events or side effects occurred. CONCLUSIONS: Early intervention in employees with mild to severe depressive complaints and high risk of future long-term sickness absence proved to be effective in preventing/reducing both sickness absence and depressive complaints.

Changes in mental health as a predictor of changes in working time arrangements and occupational mobility: results from a prospective cohort study.

OBJECTIVE: The aim of this prospective study was to gain insight into a possible causal relationship between mental health and characteristics of the work situation. METHODS: Using longitudinal data from the Maastricht Cohort Study, this study examines whether deterioration in mental health (prolonged fatigue, need for recovery, and psychological distress) results in a subsequent change in working time arrangements (assessed by means of logistic regression analysis) or occupational mobility (assessed by means of Cox regression analysis). RESULTS: Compared to employees not experiencing a deterioration in mental health, employees who became a prolonged fatigue case were more likely to reduce their working hours (OR 2.49; 95% CI 1.42-4.35) and leave a shift work job (OR 3.44; 95% CI 1.42-8.38). Employees who became a need for recovery case were more likely to reduce their working hours (OR 2.83; 95% CI 1.53-5.26) or change jobs within the company (RR 1.31; 95% CI 1.07-1.61). Employees who became a psychological distress case were more likely to change jobs within the company (RR 1.38; 95% CI 1.16-1.65) or to change jobs from one employer to another (RR 1.45; 95% CI 1.03-2.03). CONCLUSION: The results of this study provide evidence for a possible causal relationship between deterioration in mental health and subsequent change in working time arrangements or occupational mobility. These results suggest that workers adapt to the onset of a mental health problem by reducing their working hours, by leaving a shift work job, by changing jobs within the company, or by changing jobs from one employer to another.

Evaluating Model Fit in Bayesian Confirmatory Factor Analysis With Large Samples: Simulation Study Introducing the BRMSEA.

Bayesian confirmatory factor analysis (CFA) offers an alternative to frequentist CFA based on, for example, maximum likelihood estimation for the assessment of reliability and validity of educational and psychological measures. For increasing sample sizes, however, the applicability of current fit statistics evaluating model fit within Bayesian CFA is limited. We propose, therefore, a Bayesian variant of the root mean square error of approximation (RMSEA), the BRMSEA. A simulation study was performed with variations in model misspecification, factor loading magnitude, number of indicators, number of factors, and sample size. This showed that the 90% posterior probability interval of the BRMSEA is valid for evaluating model fit in large samples (N≥ 1,000), using cutoff values for the lower (<.05) and upper limit (<.08) as guideline. An empirical illustration further shows the advantage of the BRMSEA in large sample Bayesian CFA models. In conclusion, it can be stated that the BRMSEA is well suited to evaluate model fit in large sample Bayesian CFA models by taking sample size and model complexity into account.

Health effects of transitions in work schedule, workhours and overtime in a prospective cohort study.

OBJECTIVES: The aim of this study was to examine the longitudinal relationship between transitions in work schedules, workhours and overtime and changes in several self-reported health outcomes (general health, fatigue, need for recovery, and psychological distress). METHODS: Three-year follow-up data from the Maastricht Cohort Study on fatigue at work were used. Gender-stratified logistic regression analyses using generalized estimating equations were conducted for each of the dichotomized health outcomes, with control for a range of possible confounding factors. RESULTS: In this study, transitions in worktime arrangements were prospectively related to changes in several self-reported health outcomes. Substantial and significant associations were found for transitions in work schedule and the incidence of prolonged fatigue and for the need for recovery among men. Moreover, transitions in workhours affected the need for recovery among men, while they influenced general health and psychological distress among women. Finally, transitions in overtime were significantly associated with the incidence of the need for recovery among both men and women and with the incidence of psychological distress among men only. CONCLUSIONS: Transitions in worktime arrangements are related to changes in health, and studying transitions might be an important means of gaining insight into a possible causal relationship between employment and health. Given the considerable impact of worktime arrangements on the individual worker, employers, and society and the high frequency in which transitions within worktime arrangements can occur, these findings underline the need for interventions addressing worktime arrangements in order to reduce or prevent their impact on employee health.

Experiences of occupational physicians with the implementation of indicated prevention for long term sickness absence.

BACKGROUND: Functioning including work participation, is an emerging challenge in occupational health. The prevention of long term sickness absence (LTSA) through a strategy involving screening and structured early consultation (preventive strategy) was proven effective and can address participation issues. Implementation of this strategy has proven difficult. OBJECTIVE: The aim of this study is to investigate the experiences of occupational physicians (OPs) delivering a structured early consultation to office workers, in order to enhance implementation of the strategy. METHODS: In this case study, a mixed method design was used. Interviews and surveys were conducted to obtain an in-depth picture of OPs experiences. RESULTS: Factors hindering implementation in relation to the OPs were difficulties in communicating the risk of future sick leave, prioritization of other tasks, maintaining a reactive approach due to work pressure, preference for prevention on the level of the work environment, privacy issues related to labeling workers to have mental or psychosocial issues, and the biomedical model being the mental model in use. CONCLUSIONS: Implementation of the preventive strategy seems to require a more profound focus on the biopsychosocial approach. Training of relevant skills is important to achieve a focus on prevention and fostering health over the lifespan.

Smoking among shift workers: More than a confounding factor.

In studies on the cardiovascular disease risk among shift workers, smoking is considered to be a confounding factor. In a study of 239 shift and 157 daytime workers, it was found that shift work was prospectively related to increased cigarette consumption, indicating that smoking might be in the causative pathway; however, the number of study subjects was too low to warrant sound conclusions. Therefore, data from the Maastricht Cohort study were used to investigate the longitudinal relation between smoking and shift work in a much larger population. In this study, a total of 12,140 employees were followed for two years by means of self-administered questionnaires. The authors compared workers who normally worked during daytime hours only (74%) with those who worked other than day shifts (26%). Logistic regression analyses were performed, adjusting for demographic factors of age, gender, and educational level to evaluate the risk of starting to smoke (n = 25) in the group of non-smoking workers and the risk of quitting (n = 318) in the group of smoking workers. Logistic regression analysis showed a significant association between shift work and taking up smoking during the two-year follow-up (odds ratio: 1.46, p = 0.03). The risk to stop smoking was somewhat lower in shift workers (odds ratio: 0.91) but not statistically significant (p = 0.5). To conclude, this study showed that, independent of educational level, shift workers are more prone to start smoking. This finding might have important implications for studies on the health effects of shift workers and for possible interventions aimed at the reduction of the excess health risk among shift workers.

Impact of Development and Accommodation Practices on Older Workers' Job Characteristics, Prolonged Fatigue, Work Engagement, and Retirement Intentions Over Time.

OBJECTIVE: The impact of development and accommodation practices on older workers' retirement intentions was investigated in this prospective study, together with potential pathways and the role of career stage. METHODS: A subsample of full-time, older workers (n = 678) from the Maastricht Cohort Study was followed-up for 2 years. Regression analysis was conducted for three age groups. RESULTS: Development practices related positively with later retirement intentions in workers aged 55 to 59 years. The accommodation practice of demotion related negatively with later retirement intentions in worker aged at least 60 years. Decision latitude and work engagement were found to link development and accommodation practices with later retirement intentions in particular in workers aged 55 to 59 years. CONCLUSIONS: It was indicated in this prospective study that development and accommodation practices may be useful for prolonging working careers.

Critical reflections on the currently leading definition of sustainable employability.

Sustainable employability (SE) is an important topic as it deals with employees' abilities to function adequately at work and in the labor market throughout their working lives. However, until now there has been only one attempt to define SE in the international literature (1). This first definition is a valuable contribution to the field as it rightfully describes SE as a multidimensional concept, recognizes the importance of both employee and work characteristics, and acknowledges the inherently longitudinal nature of SE. Despite these merits, we argue that this definition of SE has some serious omissions that are important in capturing SE comprehensively. Specifically, we argue that the definition could be improved in various ways, namely, it should: (i) clarify which aspects of employment constitute someone's SE; (ii) not counterintuitively treat SE as a characteristic of both the job and the employee simultaneously; (iii) not be based on the insufficiently tested assumption that achieving value in work inherently leads to SE; (iv) be formulated in a way that SE can also apply to unemployed individuals; and (v) adequately specify how the inherently longitudinal dimension of SE should be addressed. We would like to contribute to the discussion by providing guidelines for a new adjusted definition of SE that could facilitate further research on this important concept and its determinants. Introduction SE is a topic of vital importance to individual employees, organizations and society alike. It generally refers to employees' capacities to function in work throughout their working life. As participation in work is important for individuals, organizations, and society as a whole, individuals' ability to function in work is essential. For individuals, work provides meaning, financial security as well as social contacts. Organizations need productive employees to survive. Also from a societal perspective, it is important that as many people as possible participate in the labor market to maintain economic welfare (1). Moreover, as a consequence of population aging (2-6), longevity, rapid changes in technology (7, 8) and changes in the nature of work (1), both the need to promote sustainable employability of individuals in society and the complexity to succeed in doing so increase even further. Only recently, van der Klink et al provided the first definition of the concept in the international scientific literature (1, p74): "Sustainable employability means that throughout their working lives, workers can achieve tangible opportunities in the form of a set of capabilities. They also enjoy the necessary conditions that allow them to make a valuable contribution through their work, now and in the future, while safeguarding their health and welfare. This requires, on the one hand, a work context that facilitates this for them and, on the other, the attitude and motivation to exploit these opportunities." This definition is accompanied by an equally recent operationalization of SE as a set of capabilities (9). Moreover, the definition itself also appeared in an earlier Dutch publication (10), which other international publications about SE most commonly refer to [ie, in comparison with other definitions in the non-international (eg, Dutch) literature] (11-13). As mentioned, the present paper provides a critical reflection on van der Klink et al's aforementioned definition of SE (1). Merits Van der Klink et al's definition of SE (1) has three important merits. First, SE is seen as a multidimensional construct. It is presented as consisting of a broad set of opportunities for employees to create value for themselves and for their employer that cover various aspects of working. Moreover, the individual's health and well-being as well as attitudinal and motivational aspects are included in the definition as well. This acknowledgement of the multidimensionality of SE is favorable, as it illustrates the complexity of the construct and of what constitutes functioning in work. This is in accordance with the International Classification of Functioning, Disability and Health (ICF) (14), in which functioning is seen from three different perspectives (body, activities, and participation). The ICF underlines the multifaceted and complex nature of functioning in which disease, environmental factors, and personal factors play a role. Similarly, the multifaceted nature of functioning is also illustrated by the fact that different disciplines focus on different aspects to understand functioning at work (15, 16). Second, SE is (partially) defined as the degree to which (i) employees are able to work throughout their entire working lives, and (ii) their work context enables them to do so. This suggests that SE is a set of interacting characteristics of the employee and the work context that codetermine the opportunities and conditions affecting employees' capacity to participate in the labor market throughout their working lives. As such, the definition describes an equal responsibility for employee and employer to maintain the employee's ability to work. This could be considered as a great merit, as research shows how strongly an employee's ability to function is influenced by both the individual, work and work-contextual factors (17). Third, van der Klink et al's definition recognizes that SE is an inherently longitudinal construct as clearly embedded in the words "throughout their working lives". This is essential as "sustainable" necessarily implies a time dimension. Need for further development Despite the aforementioned merits, there are important needs for improvement of van der Klink et al's definition of SE. First, it is not immediately clear from the definition what particular element(s) of the work situation constitute(s) SE. The paper provides some clarity by equating SE with the capability set it propagates, as evidenced by these statements: "… in an accompanying paper also published in this issue, we report on the development and validation of a questionnaire that allows for the assessment of sustainable employability based on the concept of capability" (1, p72) and "This [capability] set, in our view, represents the best possible operationalization of sustainable employability" (1, p74). However, in the paper, SE is also referred to as being determined by a worker's capability: "this model holds that an individual's sustainable employability is determined by how he or she succeeds in converting resources into capabilities, and subsequently into work functioning, in such a way that values such as security, recognition and meaning are met"(1, p72). As it is not feasible that SE is predicted by itself in the form of a capability set, perhaps the capability set does not actually refer to SE itself but rather to a favorable employment situation that may cause SE. More clarity on this issue is needed. Second, the definition seems to treat SE as a characteristic of both the job and the individual at the same time. This is counterintuitive and problematic as the job and work context may predict an individual's ability to be sustainably employed, but they can never be aspects that are part of SE. Instead, employability is a characteristic of the individual alone. Of course the individual's ability to be employed does depend on work and work-contextual factors, but these should be predictors and not be embedded in the construct itself. For an adequate definition of SE, it is essential to disentangle these relationships between causes (employment) and effects (employability). Moreover, future approaches should treat SE as an individual characteristic that is an outcome of the complex interaction between other individual, work, and work-contextual characteristics. Third, the definition and operationalization of SE assume that achieving value in work inherently predicts SE and that, therefore, SE can be conceptualized as achieving value in work. This is problematic, as before such claims can be made, such relationships need to be tested with SE as criterion. This is, however, impossible within the approach van der Klink et al provides. (1), as SE is equated with its predictor(s). Therefore, similar to the first conceptual issue, it seems unlikely that the capability set adequately reflects SE. Fourth, the definition by van der Klink et al (1) suggests that SE only applies to individuals who are employed. In the Abma et al publication (9), which accompanies van der Klink's definition paper as a validation paper, this is shown by the way in which capabilities are measured. Moreover, the definition also suggests this because individuals can only be considered to be sustainably employable if their work context enables them to achieve tangible opportunities. However, individuals who are not currently working can still be highly employable and even sustainably so, but just be between jobs. It is therefore not required for individuals to be enabled by their employer to be sustainably employable. Consequently, in line with our aforementioned points on improving the definition, being enabled by an employer to achieve value may be an important predictor of SE, but it is not necessarily part of SE itself. Moreover, future approaches to SE should define the concept in such a way that it is applicable to every individual regardless of employment status. Finally, the definition and operationalization of SE in the form of a capability set do not include any specification on how the longitudinal aspect of SE should be captured. The definition rightfully acknowledges the longitudinal dimension of SE, but its operationalization focuses solely on achieving value. Although achieving value at work may be an important predictor of SE, a complete operationalization and definition should include its longitudinal nature as well. Outlook In conclusion, while van der Klink etal's definition of SE (1) does have strong merits, it requires further improvement. The approach's main drawback is that capabilities seem more apt at describing a potentially important set of predictor(s) of SE than at capturing the construct itself. Either way, future developments in conceptualizing SE should build on the aforementioned merits, but also define SE in a way that (i) clearly labels which aspects of the employment situation constitute SE; (ii) explicitly separates causes and effects; (iii) treats SE as an individual characteristic that may be affected by other employment characteristics at the individual, work, and work-contextual levels; (iv) makes the concept applicable to any individual regardless of their employment status; and (v) clearly addresses the longitudinal nature of SE as embedded in the word "sustainable". These guidelines should not only enable the development of an appropriate definition of SE but also a conceptually sound way of measuring the construct.

The Impact of Physical Work Demands on Need for Recovery, Employment Status, Retirement Intentions, and Ability to Extend Working Careers: A Longitudinal Study Among Older Workers.

OBJECTIVE: Prospectively investigating whether different approaches of physical work demands are associated with need for recovery (NFR), employment status, retirement intentions, and ability to prolong working life among older employees from the industry and health care sector. METHODS: A subsample from the Maastricht Cohort Study was studied (n = 1126). Poisson, Cox, and logistic regression analyses were performed to investigate outcomes. RESULTS: Perceiving physical work demands as strenuous was associated with higher NFR. Continuous physical strain was associated with being out of employment 4 years later. Employees with the highest amount of physical work demands perceived they were less able to prolong working life, although no significant associations between physical work demands and retirement intentions were found. CONCLUSIONS: Overall, physical work demands were associated with adverse outcomes, with divergent insights for the different approaches of physical work demands.

Approaches for predicting long-term sickness absence. Re: Schouten et al. "Screening manual and office workers for risk of long-term sickness absence: cut-off points for the Work Ability Index".

We read with much interest the article of Schouten et al (1) on identifying workers with a high risk for future long-term sickness absence using the Work Ability Index (WAI). The ability to identify high-risk workers might facilitate targeted interventions for such workers and, consequently, can reduce sickness absence levels and improve workers' health. Earlier studies by both Tamela et al (2), Kant et al (3), and Lexis et al (4) have demonstrated that such an approach, based on the identification of high-risk workers and a subsequent intervention, can be effectively applied in practice to reduce sickness absence significantly. The reason for our letter on Schouten et al's article is twofold. First, by including workers already on sick leave in a study predicting long-term sick leave will result in an overestimation of the predictive properties of the instrument and biased predictors, especially when also the outcome of interest is included as a factor in the prediction model. Second, we object to the use of the term "screening" when subjects with the condition screened for are included in the study. Reinforced by the inclusion of sickness absence in the prediction model, including workers already on sick leave will shift the focus of the study findings towards the prediction of (re)current sickness absence and workers with a below-average return-to-work rate, rather than the identification of workers at high risk for the onset of future long-term sickness absence. The possibilities for prevention will shift from pure secondary prevention to a mix of secondary and tertiary prevention. As a consequence, the predictors of the model presented in the Schouten et al article can be used as a basis for tailoring neither preventive measures nor interventions. Moreover, including the outcome (sickness absence) as a predictor in the model, especially in a mixed population including workers with and without the condition (on sick leave), will result in biased predictors and an overestimation of the predictive value. A methodological approach of related issues is provided in the works of Glymour et al (5) and Hamilton et al (6). This phenomenon is even more clearly illustrated by the predictive properties of the workability index, as described by Alavinia et al (7, page 328), which reported that "when adjusted for individual characteristics, lifestyle factors, and work characteristics, two dimensions of the WAI were significant predictors for both moderate and long durations of sickness absence: (i) the presence of sickness absence in the past 12 months prior to the medical examination and (ii) experienced limitations due to health problems." So, when applied to the study by Schouten et al (1), this means that most of the predictive value would be related to the factors "sickness absence in the past 12 months". In addition, we object to the use of the term "screening" in the Schouten et al study as it includes workers with the intended outcome (long-term sickness absence). One can identify three separate aims to study the longitudinal association between risk factors and subsequent long-term sickness absence: (i) to establish causal risk factors for long-term sickness absence, often to find clues for primary preventive strategies (beyond the scope here); (ii) to identify high-risk workers who are still at work and might benefit from an intervention before sickness absence occurs (secondary prevention); and (iii) to identify workers on sick leave who might suffer a below-average return-to-work rate or have a high risk for the recurrence of (long-term) sickness absence and might benefit from intensification or optimization of the return-to-work process (tertiary prevention). In this light, one needs to separate screening instruments from predictive instruments and reserve the term "screening" for the situation as defined by Wilson and Junger (8, page 7): "The object of screening for disease is to discover those among the apparently well who are in fact suffering from disease" (ie, situations of secondary prevention). This means that, when applying this definition on long-term sickness absence under the precondition that the individuals are still at work, screening enables the identification of high-risk individuals in the early "stages" of a "disease" that can progress into long-term sickness absence. In the case of the Schouten et al study, the population at risk, as derived from their predictive instrument, consists of workers with and without sickness absence, and as such excludes the use of the term "screening" in this case. To conclude, we have substantiated that, in addition to correct usage of the term "screening", careful selection of the study population, predictors and most importantly the aim of the predictive model are essential in the process of developing predictive instruments aimed at identifying workers at high risk of long-term sickness absence. Two fundamentally different approaches are possible. One approach aims at identifying workers on sick leave with either a below-average chance to return to work an/or a high risk for a successive episode of long-term sickness absence. From a methodological and practical point of view, such an instrument should be developed and validated among workers already on sick leave. A second approach aims at identifying workers who are still at work but at high risk for future long-term sickness absence. To develop and validate such an instrument, a study sample where workers already on sick leave are excluded is a prerequisite. Such instruments fit in a pro-active approach of preventing future sickness absence, where an early intervention can be offered to those workers with an increased risk for future sickness absence.

Antecedents and consequences of work-family conflict: a prospective cohort study.

This study examined both risk factors for the onset of work-family conflict and consequences in terms of need for recovery and prolonged fatigue for men and women separately. Two-year follow-up data from the Maastricht Cohort Study on "Fatigue at Work" (n = 12,095) were used. At baseline, the prevalence of work-family conflict was 10.8% (9.0% in women; 11.1% in men), the cumulative incidence at 1 year follow-up was 5.1%. For men, several work-related demands, shift work, job insecurity, conflicts with coworkers or supervisor, having full responsibility for housekeeping, and having to care for a chronically ill child or other family member at home were risk factors for the onset of work-family conflict, whereas decision latitude and coworker and supervisor social support protected against work-family conflict. In women, physical demands, overtime work, commuting time to work, and having dependent children were risk factors for work-family conflict, whereas domestic help protected against work-family conflict at 1 year follow-up. Work-family conflict was further shown to be a strong risk factor for the onset of elevated need for recovery from work and fatigue.

Prevalence of common infections among employees in different work schedules.

This study examined the prevalence of common infections among employees in different work schedules. Self-administered questionnaire data from the Maastricht Cohort Study on "Fatigue at Work" (n = 12,140) were used. Job title was used as a matching variable between day and shift workers to control for their different work environment. We used a multilevel analysis of a two-level structure, in which the individual employees (level 1) were nested within job titles (level 2), adjusted for demographics, longstanding disease, health behavior, work-related factors, fatigue and sleep quality. Results from the multilevel analyses showed that, compared to day work, shift work was associated with a higher risk for common infections, with the highest risk in three-shift workers. Compared to day work, shift work was further associated with differences in health, health behavior, sleep, fatigue and perceived job characteristics, factors that may influence the occurrence of infections and should be taken into account in future studies as well.

Impact of worktime arrangements on work-home interference among Dutch employees.

OBJECTIVES: This study examined the effects of different worktime arrangements on work-home interference while taking into account other work-related factors, private situation and health status, explored gender differences in this relation, and examined reciprocal effects between workhours and work-home interference. METHODS: Data from the Maastricht cohort study on fatigue at work were used with 8 months of follow-up (N=6947 at baseline). RESULTS: Worktime arrangements were related to work-home interference among the men and women, even after control for confounding. As compared with daywork, baseline shiftwork was associated with higher work-home interference over time. Within daywork, full-time work was prospectively related to higher work-home interference than part-time work was. For full-timers, baseline overtime work, hours of overtime work, change in number of workhours, and commuting time were related to higher work-home interference over time, whereas compensation for overtime work, familiarity with work roster, ability to take a day off, and a decrease in workhours at own request were associated with less work-home interference. For the part-timers, baseline overtime work and commuting time were related to higher work-home interference over time, whereas compensation for overtime, flexible workhours, and ability to take a day off were protective against work-home interference. Reciprocal relations between work-home interference and workhours were also found. CONCLUSIONS: Worktime arrangements are clearly related to work-home interference. Because reciprocal effects exist as well, important selection processes may exist. Nevertheless, specific characteristics of worktime arrangements could constitute useful tools for reducing work-home interference.

Direction of shift rotation among three-shift workers in relation to psychological health and work-family conflict.

OBJECTIVES: The aim of the present study was to investigate whether the direction of shift rotation was related to the need for recovery, fatigue, sleep quality, work-family conflict, and leisure time among three-shift workers. METHODS: Data of 95 workers in forward-rotating three-shift work and 681 workers in backward-rotating three-shift work, with 32 months of follow-up, in the Maastricht cohort study (N=12,095) were used. Both cross-sectional and longitudinal analyses were carried out. RESULTS: A backward rotation schedule was prospectively related to an increased need for recovery [relative risk (RR) 2.88, 95% confidence interval (95% CI) 1.06-7.81] and poor general health (RR 3.21, 95% CI 1.32-7.83), as compared with a forward rotation schedule. Adjustment for demographic and health variables and the characteristics of the work environment did not alter these relations considerably. Furthermore, a forward rotation schedule was prospectively related to less work-family conflict and better sleep quality over the 32 months of follow-up. Finally, high levels of fatigue, need for recovery, poor sleep quality, poor general health, insufficient leisure time, and work-family conflict at first measurement were associated with an increased risk of leaving shiftwork during the follow-up. CONCLUSIONS: Optimization of shiftwork schedules, in terms of shift rotation, seems a promising method for decreasing the negative impact accompanying shiftwork. Future studies should investigate whether these findings for three-shift workers are applicable to other shiftwork schedules as well. Furthermore, this study clearly illustrates the existence of secondary selection processes among shiftworkers and thereby emphasizes the complexity of valid shiftwork research.