Higher risks when working unusual times? A cross-validation of the effects on safety, health, and work-life balance.

PURPOSE: Replication and cross-validation of results on health and safety risks of work at unusual times. METHODS: Data from two independent surveys (European Working Conditions Surveys 2005 and 2010; EU 2005: n = 23,934 and EU 2010: n = 35,187) were used to examine the relative risks of working at unusual times (evenings, Saturdays, and Sundays) on work-life balance, work-related health complaints, and occupational accidents using logistic regression while controlling for potential confounders such as demographics, work load, and shift work. RESULTS: For the EU 2005 survey, evening work was significantly associated with an increased risk of poor work-life balance (OR 1.69) and work-related health complaints (OR 1.14), Saturday work with poor work-life balance (OR 1.49) and occupational accidents (OR 1.34), and Sunday work with poor work-life balance (OR 1.15) and work-related health complaints (OR 1.17). For EU 2010, evening work was associated with poor work-life balance (OR 1.51) and work-related health complaints (OR 1.12), Saturday work with poor work-life balance (OR 1.60) and occupational accidents (OR 1.19) but a decrease in risk for work-related health complaints (OR 0.86) and Sunday work with work-related health complaints (OR 1.13). Risk estimates in both samples yielded largely similar results with comparable ORs and overlapping confidence intervals. CONCLUSIONS: Work at unusual times constitutes a considerable risk to social participation and health and showed structurally consistent effects over time and across samples.

[Health and safety regulations concerning working time according to the FRG-using the example of the COVID-19 working time ordinance (COVID-19-ArbZV)]. / Arbeits(zeit)schutz nach Art der BRD ­ am Beispiel der COVID-19-Arbeitszeitverordnung.

Following a short discussion concerning the contradictions of the COVID-19 working time ordinance (COVID-19-ArbZV) with the existing ergonomics evidence on the design of working time and its effects on safety, health and wellbeing possible effects of this regulation with regard to the risks of accidents, health and social impairments have been estimated using computer based risk assessments for selected working time systems constructed in accordance with the ordinance.The results show significantly increased risk estimates for all analyzed systems and for all domains, demonstrating a sincere loss in the effectiveness and efficiency of health and safety prevention. Applying these results to the medical sector leads to the conclusion of an elsewhere empirically demonstrated reduction in patient care and patient safety.It is argued that increasing working and reducing rest times of the available work force is not an effective solution for problems of lacking human resources due to its adverse side effects on employees and third parties. Health and safety protection via working time regulations based on ergonomics evidence obviously is not a prominent approach in the FRG.Practical Relevance: A reorientation towards health and safety approaches taking ergonomics evidence into due account is required in the FRG.

Development and preliminary validation of an index for indicating the risks of the design of working hours to health and wellbeing.

BASS 4, a computer program for the design and evaluation of workings hours, is an example of an ergonomics-based software tool that can be used by safety practitioners at the shop floor with regard to legal, ergonomic, and economic criteria. Based on experiences with this computer program, a less sophisticated Working-Hours-Risk Index for assessing the quality of work schedules (including flexible work hours) to indicate risks to health and wellbeing has been developed to provide a quick and easy applicable tool for legally required risk assessments. The results of a validation study show that this risk index seems to be a promising indicator for predicting risks of health complaints and wellbeing. The purpose of the Risk Index is to simplify the evaluation process at the shop floor and provide some more general information about the quality of a work schedule that can be used for triggering preventive interventions. Such a risk index complies with practitioners' expectations and requests for easy, useful, and valid instruments.

Extended working hours and health.

Statistical analyses of the relation between the amount of working hours and impairments to health, based on data from a European survey on working conditions in 2000, clearly reveal that there is a substantial correlation between the number of working hours per week and the frequencies of health complaints. This applies to both musculo-skeletal disorders as well as to psycho-vegetative complaints. The relationship of the duration of the exposure to working conditions to health impairments is moderated by a great number of individual (e.g., age) and situational (e.g., shift-work) variables, showing additive or interactive effects for which selected examples have been presented. In general, however, there is a consistent functional relationship between the number or working hours and their effects on the workers that holds over a great variety of conditions. It is argued that requests for extending working hours should thus be handled with care.

A new approach for evaluating flexible working hours.

Recent studies on flexible working hours show at least some of these working time arrangements seem to be associated with impairing effects of health and well-being. According to available evidence, variability of working hours seems to play an important role. The question, however, is how this variability can be assessed and used to explain or predict impairments. Based on earlier methods used to assess shift-work effects, a time series analysis approach was applied to the matter of flexible working hours. Data on the working hours of 4 week's length of 137 respondents derived from a survey on flexible work hours involving 15 companies of different production and service sectors in Germany were converted to time series and analyzed by spectral analysis. A cluster analysis of the resulting power spectra yielded 5 clusters of flexible work hours. Analyzing these clusters for differences in reported impairments showed that workers who showed suppression of circadian and weekly rhythms experienced severest impairments, especially in circadian controlled functions like sleep and digestion. The results thus indicate that analyzing the periodicity of flexible working hours seems to be a promising approach for predicting impairments which should be investigated further in the future.

Flexible working hours, health, and well-being in Europe: some considerations from a SALTSA project.

The project brought together researchers from 9 EU-Countries and resulted in a number of actions, in particular the following: (a) There is an urgent need of defining the concept of flexible working hours, since it has been used in many different and even counterintuitive ways; the most obvious distinction is where the influence over the working hours lies, that is between the "company-based flexibility" and the "individual-oriented flexibility"; (b) The review of the Legislation in force in the 15 European countries shows that the regulation of working times is quite extensive and covers (Council Directive 93/104/EC) almost all the various arrangements of working hours (i.e., part-time, overtime, shift, and night work), but fails to provide for flexibility; (c) According to the data of the Third EU Survey on Working Conditions, longer and "irregular" working hours are in general linked to lower levels of health and well-being; moreover, low (individual) flexibility and high variability of working hours (i.e., company-based flexibility) were consistently associated with poor health and well-being, while low variability combined with high autonomy showed positive effects; (d) Six substudies from different countries demonstrated that flexible working hours vary according to country, economic sector, social status, and gender; overtime is the most frequent form of company-based flexibility but has negative effects on stress, sleep, and social and mental health; individual flexibility alleviates the negative effects of the company-based flexibility on subjective health, safety, and social well-being; (e) The literature review was able to list more than 1,000 references, but it was striking that most of these documents were mainly argumentative with very little empirical data. Thus, one may conclude that there is a large-scale intervention ongoing in our society with almost completely unknown and uncontrolled effects. Consequently, there is a strong need for systematic research and well-controlled actions in order to examine in detail what flexible working hours are considered, what and where are their positive effects, in particular, as concerns autonomy, and what regulation seem most reasonable.

Diversity and equity: dealing with biological and social differences.

In the context of the design of working hours inequities in health associated with biological, psychological, social, and socioeconomic diversities can be observed. The paper first tries to set up a frame of reference for a discussion of this topic, relating to the Universal Declaration of Human Rights and some recent discussions on equity in health and then goes into some factors that produce inequities in health in the context of the design of working hours, dealing with sex or gender, age and job age, personality traits, marital status, social support, diversities in values, and socio-economic differences; the discussion deals with approaches on how to deal with these differences and inequities.

Health and psychosocial effects of flexible working hours.

OBJECTIVE: To examine whether any impairments in health and social lives can be found under different kinds of flexible working hours, and whether such effects are related to specific characteristics of these working hours. METHODS: Two studies -- a company based survey (N=660) and an internet survey (N=528) -- have been conducted. The first one was a questionnaire study (paper and pencil) on employees working under some 'typical' kinds of different flexible working time arrangements in different companies and different occupational fields (health care, manufacturing, retail, administration, call centres). The second study was an internet-based survey, using an adaptation of the questionnaire from the first study. RESULTS: The results of both studies consistently show that high variability of working hours is associated with increased impairments in health and well-being and this is especially true if this variability is company controlled. These effects are less pronounced if variability is self-controlled; however, autonomy does not compensate the effects of variability. CONCLUSIONS: Recommendations for an appropriate design of flexible working hours should be developed in order to minimize any impairing effects on health and psychosocial well-being; these recommendations should include -- besides allowing for discretion in controlling one's (flexible) working hours -- that variability in flexible working hours should be kept low (or at least moderate), even if this variability is self-controlled.

BASS 4: a software system for ergonomic design and evaluation of working hours.

OBJECTIVE: To extend an existing computer programme for the evaluation and design of shift schedules (BASS 3) by integrating workload as well as economic aspects. METHODS: The redesigned prototype BASS 4 includes a new module with a suitable and easily applicable screening method (EBA) for the assessment of the intensity of physical, emotional and cognitive workload components and their temporal patterns. Specified criterion functions based on these ratings allow for an adjustment of shift and rest duration according to the intensity of physical and mental workload. Furthermore, with regard to interactive effects both workload and temporal conditions, e.g. time of day, are taken into account. In a second new module, important economic aspects and criteria have been implemented. Different ergonomic solutions for scheduling problems can now also be evaluated with regard to their economic costs. RESULTS: The new version of the computer programme (BASS 4) can now simultaneously take into account numerous ergonomic, legal, agreed and economic criteria for the design and evaluation of working hours. CONCLUSIONS: BASS 4 can now be used as an instrument for the design and the evaluation of working hours with regard to legal, ergonomic and economic aspects at the shop floor as well as in administrative (e.g. health and safety inspection) and research problems.

Health effects of supplemental work from home in the European Union.

Internationalization and technological developments have changed the work organization in developed and developing industrial economies. Information and communication technologies, such as computers and smartphones, are increasingly used, allowing more temporal and spatial flexibility of work. This may lead to an increase in supplemental work, i.e. constant availability or working in addition to contractually agreed work hours. This in turn extends work hours and leads to work hours in evenings and weekends, causing interferences of work hours with biological and social rhythms for sleep, recovery and social interaction. However, empirical findings on the effects of supplemental work and work hours on occupational health are rather scarce. Therefore, the aim of this study was to investigate the association between (1) work-related contacts outside of regular work hours and (2) working in the free time with self-reported work-related health impairments in the fourth and fifth European Working Conditions Surveys (EWCS 2005, EWCS 2010). Out of these cross-sectional, large-scale surveys, data on n = 22 836 and n = 34 399 employed workers were used for weighted logistic regression analyses. About half of the sample reported at least occasional supplemental work. The results showed an increased risk of reporting at least one health problem for employees who had been contacted by their employer (EWCS 2005), or worked in their free time to meet work demands (EWCS 2010) in the last 12 months, compared to those reporting no supplemental work or work-related contacts during free time. These results were controlled for demographic variables, physical and mental work load, worker autonomy, and several work hours characteristics (e.g. hours per week, unusual and variable hours). The risk of reporting health problems was increased by being contacted both sometimes (Odds Ratio [OR] 1.26, 95% Confidence Interval [CI] 1.14-1.39) and often (OR 1.13, 95% CI 1.02-1.25), whereas the frequency of working in the free time showed a clear dose-response effect (sometimes: OR 1.14, 95% CI 1.04-1.24; often: OR 1.60, 95% CI 1.47-1.75), both compared to the category "never". The findings, thus, indicate that even a small amount of supplemental work beyond contractually agreed work hours may increase the risk of work-related health impairments. Working in the free time was associated with a substantial risk increase and might be a better indicator for actual work load than being contacted by the employer outside of contractually agreed work hours. Thus, in order to minimize negative health effects, availability requirements for employees outside their regular work hours should be minimized. While these effects definitely need further study, especially regarding a quantification of actual supplemental work and its temporal location, addressing the company culture and using incentives and policies might be options to reduce the amount of supplemental work and maintain the risks of health impairments in the working population at a lower level.

The validity of the risk index for comparing the accident risk associated with different work schedules.

Although it is known that there is an association between working hours and occupational accidents, there are only few tools which allow for an assessment of the risk associated with different working time arrangements, none of them validated yet by independent samples. Promising tools like the risk index (RI), assessed via the fatigue and risk index calculator, thus need to be validated. Since analyses on the validity of the RI based on individual data found only moderate associations between the RI and the actual accident risk, the question arises, whether a validation based on grouped data yields more promising results. Thus, the validity of the RI was re-examined, using aggregated data, i.e. pooling several individuals into groups of respondents according to their RI-score and performing calculations on the group level in order to control for individual and random variation. The study sample (n=337) was derived from an Internet survey on working hours and health, which contained information on working hours over four weeks and on the occurrence of an occupational accident during the last 12 months. Two models of aggregation were used: a distribution based and a criterion based classification, resulting in four RI groups each. Accident rates for each group were calculated and compared via χ(2)-analyses and fitting trends to the data. Results show, for both models of aggregation, that the accident rate increased exponentially with an increasing RI. Risk was 3.7 times (distribution based aggregation) and 6.5 times (criterion based aggregation) higher in the highest compared to the lowest RI-groups. The exponential trend explained 92% (distribution based aggregation) and 98% (criterion based aggregation) of the variance, respectively. Analyses for homogeneous subgroups (e.g., service sector, and workers with high workload) showed similar trends. Thus the analyses based on aggregated data indicated a considerable and consistently higher validity of the RI than the earlier analyses based on individual data, irrespective of the model of aggregation. These results are quite promising although further analyses based on larger samples are needed to confirm these findings and in order to further develop the RI or similar indices.

When work calls-associations between being contacted outside of regular working hours for work-related matters and health.

Boundaries between work and private life are diminishing, but little is known on how this influences worker health. Therefore, we examined the association between work-related contacts outside of regular working hours by e-mail or phone and self-reported health in a representative sample of European employees (n = 23 760). The risk of reporting ≥1 health problem(s) was increased in workers contacted sometimes (odds ratio [OR]: 1.16, 95% confidence interval [CI]: 1.06-1.27) or often (OR: 1.23, 95% CI: 1.12-1.34) as compared with never, controlling for several demographic and workplace characteristics. Further research is needed to quantify work and nonwork patterns and their health effects.

Effects of lifetime exposure to shiftwork on fitness for duty in police officers.

Aging and demographic changes in Europe and other global economies have led to a discussion about postponing the legal retirement age; however, health and safety consequences for the workforce have not yet been examined. Thus, the aim of this study was to investigate the effects of lifetime exposure to shiftwork on health impairments and fitness for duty. Two samples of the police force from one of the states of the Federal Republic of Germany were used. One sample was collected in 2008-2009 with a self-administered Internet questionnaire (n = 705); the other sample was derived from employment records provided by the police force of the same federal state for the years 2002-2009 (n = 2460). Both samples contained information about the number of years worked in shiftwork across the entire working life and impairments to fitness for duty assessed by occupational physicians. Thus, the number of years of shiftwork until the diagnosis of the first reduction in fitness for duty could be calculated. Survival analyses were performed to estimate the risk (hazard rate) for experiencing a reduction in fitness for duty across lifetime exposure to shiftwork in years, controlling for age, sex, work type, and police district. Hazard estimates were compared across both samples to cross-validate the results. The findings indicated an increase in the risk of reduced fitness for duty with increasing number of years in shiftwork during the working life in both samples. The hazard rates followed an exponential trend, indicating a rapid increase in health impairments in particular beyond 20 yrs of shiftwork. These findings were consistent in both samples, collected with different methods and over different time periods, thus indicating high validity. Therefore, occupational stress factors, such as exposure to shiftwork, need to be taken into account when discussing the postponement of the legal retirement age.

Working on Sundays­effects on safety, health, and work-life balance.

Several attributes of the work schedule can increase the risk of occupational injuries and accidents, health impairments, and reduced social participation. Although previous studies mainly focused on the effects of shiftwork and long working hours on employee health and safety, there is little evidence of a potential negative impact of working Sundays on the incidence of occupational accidents, health impairments, and work-life balance. A representative sample of employed workers in 31 member and associated states of the European Union (n = 23,934) served as the database for a cross-sectional analysis. The sample was collected via face-to-face interviews in the year 2005. The association of the risks of occupational accidents, health impairments, and decreases in work-life balance with working Sundays was calculated using logistic regression models, controlling for potential confounders, such as shiftwork, workload, and demographic characteristics. The results indicated that working one or more Sundays/month was associated with increase both in the risk of reporting one or more health impairments (odds ratio [OR]: 1.17, 95% confidence interval [CI]: 1.06-1.29) and poorer work-life balance (OR: 1.15, 95% CI: 1.02-1.28). These effects remained after controlling for potentially confounding factors, such as other work schedule attributes, intensity of physical and mental workload, and individual characteristics. Furthermore, working Sundays was also related to increased risk of occupational accidents within the last year (OR: 1.34, 95% CI: 1.03-1.73). Controlling again for individual, workload, and working-time characteristics, a significant association with accident risk, however, remained only in work sectors with low a priori risk of occupational accidents (OR: 1.40, 95% CI: 1.02-1.91), although the increased risk could be observed for both medium and high a priori risk sectors working Sundays (without controlling for additional confounders). The results thus indicate that the detrimental effects of working Sundays on safety, health, and social well-being should be taken into account when designing work schedules. The potential hazards to employees' safety, health, and work-life balance, in particular, should be considered in discussions concerning extending work on Sundays in certain sectors, e.g., retail.

The effects of extended working hours on health and social well-being--a comparative analysis of four independent samples.

Using structural equation modeling, it can be shown that long weekly working hours and work on weekends, nights, and in shifts have detrimental effects on psychovegetative health. Employees' reported subjective work-life balance also decreases with increasing number of hours worked/week, days worked on weekends, or at nights, and with working shifts. A decrease in work-life balance in turn increases the risk of psychovegetative impairments (PVIs). Thus, long and unusual working hours increase the risk of psychovegetative health impairments both directly and indirectly, moderated by the subjective work-life balance. In fact, the indirect effects of working time on PVIs via the work-life balance seem to be stronger than the direct effects. Results of a cross-validation study of four independent and representative samples from Germany and the European Union (N > 50,000) indicate high structural stability of these results and thus an increased validity and range for generalization.

The validity of the fatigue and risk index for predicting impairments of health and safety under different shift schedules in the context of risk assessments.

In Germany, risk assessment of the working time arrangement is legally required, and within this context the authors assessed the usefulness of the fatigue and risk index (FRI) to predict any detrimental effects to health and safety. This assessment was made using data from two different surveys. Each contained records of working hours over a 4-wk period plus information on occupational accidents and health complaints. The independent variables drawn from the FRI parameters included the maxima, means, variances, and index factor scores. Phi-correlations between the FRI (dichotomized to the index of the reference system) and the incidence of an occupational accident were rather moderate, with a maximum correlation of .22 using the mean fatigue index (FI). Correlations between the two index factor scores and health complaints (sleep problems, stomach pain, eructation/heartburn) revealed the FI component, but not the risk index (RI) component, was related to those health complaints. Forward stepwise logistic regression analysis indicated the FI (but not the RI) predicted occupational accidents (FI(factor) odds ratio [OR] = 1.90, confidence interval [CI] 1.23-2.93). When using multiple regression analyses, the FI was able to predict sleep problems and other circadian related-problems, but the regression coefficients were moderate. In general, the results were not considered sufficient to justify a mandatory use of the FRI.

The interference of flexible working times with the utility of time: a predictor of social impairment?

Periodic components inherent in actual schedules of flexible working hours and their interference with social rhythms were measured using spectrum analysis. The resulting indicators of periodicity and interference were then related to the reported social impairments of workers. The results show that a suppression of the 24 and the 168 h (seven-day) components (absence of periodicity) in the work schedules predicts reported social impairment. However, even if there are relatively strong 24 and 168 h components left in the work schedules, their interference with the social rhythm (using the phase difference between working hours and the utility of time) further predicts impairment. The results thus indicate that the periodicity of working hours and the amount of (social) desynchronization induced by flexible work schedules can be used both for predicting the impairing effects of the specific work schedules on social well-being as well as for the design of socially acceptable flexible work hours.

The interference of flexible working times with the circadian temperature rhythm--a predictor of impairment to health and well-being?

In order to analyze whether impairments to health and well-being under flexible working hours can be predicted from specific characteristics of the work schedules, periodic components in flexible working hours and their interference with the circadian temperature rhythm were analyzed applying univariate and bivariate spectrum analyses to both time series. The resulting indicators of spectral power and phase shift of these components were then related to reported health impairments using regression analysis. The results show that a suppression of both the 24 and the 168 h components in the work schedules (i.e., a lack of periodicity) can be used to predict reported health impairments, and that if there are relatively strong 24 and 168 h components left in the work schedules, their phase difference with the temperature rhythm (as an indicator of the interference between working time and the circadian rhythm) further predicts impairment. The results indicate that the periodicity of working hours and the amount of (circadian) desynchronization induced by flexible work schedules can be used for predicting the impairing effects of flexible work schedules on health and well-being. The results can thus be used for evaluating and designing flexible shift rosters.

Sensitivity and diagnosticity of the 0.1-Hz component of heart rate variability as an indicator of mental workload.

We investigated whether the 0.1-Hz component of heart rate variability (HRV) allows one to discriminate among levels of mental work stress induced by different types of tasks (diagnosticity) as well as among those induced by different levels of difficulty (sensitivity). Our 14 participants were presented 14 tasks of the Advisory Group for Aerospace Research and Development Standardized Tests for Research with Environmental Stressors battery in a repeated-measures design. Sufficient sensitivity was obtained for a discrimination between work and rest, but we found no support for a more fine-grained sensitivity. Concerning diagnosticity, only the grammatical reasoning task could be discriminated from all other tasks, indicating for this task a level of mental strain comparable to rest, which was in contrast with the results both for perceived difficulty and performance. We propose that HRV is an indicator for time pressure or emotional strain, not for mental workload, given that it seems to allow discrimination between tasks with and without pacing. Application of this research argues against using HRV as a measure of mental and especially cognitive workload, particularly where system safety or occupational risks may be at stake (e.g., when evaluating operator tasks or interface design in control room operations).