Danielle C. L. Mohren

Prevalence of common infections among employees in different work schedules.

Learning ObjectivesDiscuss possible mechanisms through which the work schedule—particularly “shift work,” which includes nighttime work—might influence the risk of contracting common infections.Compare the demographic and behavioral features of day workers and shift workers.Contrast the prevalence of common infections in day and shift workers, adjusting for type of work. 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.

DEPRESSED MOOD IN THE WORKING POPULATION: ASSOCIATIONS WITH WORK SCHEDULES AND WORKING HOURS

The impact of working time arrangements (WTA) on health has been studied extensively. Still, little is known about the interrelation between work schedules, working hours, and depressed mood. For work schedules, the underlying assumptions regarding depressed mood refer to a disturbance of social and biological rhythms, whereas for working hours, the assumptions relate to workload and work capacity. Conversely, depressed mood may urge an employee to adjust his/her work schedule and/or number of working hours/week (h/wk). The aim of this study was to assess the association between work schedule and working hours with depressed mood. Using baseline data from the Maastricht Cohort Study, depressed mood in day work was compared with depressed mood in different shiftwork schedules (n = 8843). Within day work, several categories of working h/wk were studied in association with depressed mood (n = 7217). The association between depressed mood and several aspects of overtime was assessed separately. Depressed mood was measured with a dichotomous item: “Did you feel down every day over the last two weeks?” Separate logistic regression analyses were conducted for men and women, with adjustments for potential confounders. The odds ratio (OR) for depressed mood was greater for men involved in shiftwork than for men only involved in day work (three-shift OR = 2.05 [95% confidence interval, CI 1.52–2.77]; five-shift OR = 1.34 [95% CI 1.00–1.80]; irregular-shift OR = 1.79 [95% CI 1.27–2.53]). In female employees, five-shift work was associated with a higher prevalence of depressed mood (OR = 5.96 [95% CI 2.83–12.56]). Regarding the number of working h/wk, men working <26 h/wk had a higher prevalence of depressed mood than men working 36–40 h/wk (OR = 2.73 [95% CI 1.35–5.52]). After conducting trend analyses, a significant decreasing trend was found in men, whereas an increasing trend was found in women working a high number of hours. Furthermore, a dose-response relationship was present in men regarding the number of overtime h/wk. This study showed that different work schedules and working hours are associated with depressed mood. Shiftwork was related to a higher prevalence of depressed mood than day work. The association was more pronounced for male employees. Regarding the number of working h/wk, male and female employees showed an opposite trend in depressed mood. Because of the possibility of a healthy worker effect and the possibility of a reciprocal relationship between WTA and depressed mood, the reported relation might be underestimated. This study has illustrated that occupational physicians, who deal with depressed mood among workers, should carefully consider the impact of WTA. (Author coorespondence: Karolien.Driesen@epid.unimaas.nl)

Psychological job demands as a risk factor for common cold in a Dutch working population

OBJECTIVE We investigated the effect of Psychological Job Demands (PJD) on the occurrence of the clinical symptoms of common cold. METHODS Subjects, participating in a large prospective cohort study on psychological determinants of fatigue at work, were asked to fill in a questionnaire on the occurrence of common cold during the previous four months. High PJD were considered as a potential risk factor. Other factors such as age, gender, and having young children were considered as potential confounders. RESULTS In logistic regression analysis, the adjusted odds ratio (OR) for having a recent cold in subjects reporting high PJD vs. those reporting low PJD was 1.20 (95% confidence interval (CI), 1.08-1.33). A higher risk emerged among those with young children (OR, 1.70; 95% CI, 1.47-1.96), those having a history of asthma (OR, 1.69; 95% CI, 1.28-2.22), or being under the age of 40 (OR, 1.28; 95% CI, 1.14-1.43) and among smokers (OR, 1.23; 95% CI, 1.09-1.38). CONCLUSION The results support an association between PJD and common cold. In spite of the almost inevitable shortcoming of a large cohort study using questionnaires, this study gave us the opportunity to study the relationship between common cold and work-related factors in a nonexperimental setting with participants observed in a natural environment with all the normal everyday hassles.

Associations between infections and fatigue in a Dutch working population: Results of the Maastricht Cohort Study on Fatigue at Work

The relationship between fatigue and common infections was further explored, as part of a 3 year prospective cohort study on Fatigue at Work. The current study is based on seven successive questionnaires, covering the first 2 years of follow-up. The overall response at baseline was 45% (n = 12,140). On T1 10,592 (87.2% compared to baseline response) employees returned the questionnaire. For T2, T3, T4, T5 and T6, 10,270 (84.6%), 9655 (79.5%), 8956 (73.8%), 8692 (71.6%) and 8070 (66.5%) employees respectively returned the questionnaire. Self-administered questionnaires were used to determine the level of fatigue with the Checklist Individual Strength (CIS) and the occurrence of common cold, flu-like illness and gastroenteritis. Regression analysis using generalized estimated equations (GEE) were used for data analysis. We found a cross-sectional relationship between fatigue and the infections flu-like illness and gastroenteritis, and a longitudinal relationship between an infection as a predictor of fatigue. For fatigue as a predictor of an infection, we found odds ratios (ORs) of 1.35 (confidence interval (CI) 1.28–1.42) for flu-like illness and 1.33 (CI: 1.25–1.42) for gastroenteritis. The highest incidence of infections was found among employees who reported high fatigue levels on two successive occasions. The increased incidence of infections, is regarded as a substantial effect of fatigue because it is associated with significant absenteeism from work and leads to discomfort.

CHANGES IN WORKING TIME ARRANGEMENTS OVER TIME AS A CONSEQUENCE OF WORK-FAMILY CONFLICT

Existing longitudinal studies on the relationship between working time arrangements (WTA) and work-family conflict have mainly focused on the normal causal relationship, that is, the impact of WTA on work-family conflict over time. So far, however, the reversed relationship, that is, the effect of work-family conflict on adjustments in WTA over time, has hardly been studied. Because work-family conflict is highly prevalent in the working population, further insight in this reverse relationship is invaluable to gain insight into secondary selection processes. The aim of this study is to investigate whether work-family conflict is prospectively related to adjustments in work schedules, working hours, and overtime work, and to explore sex differences and different time lags in this relation. Data of the prospective Maastricht Cohort Study were used. To study the effect of work-family conflict on a change from shift- to day work over 32 months of follow-up, male three-shift (n = 727), five-shift (n = 932), and irregular-shift (n = 451) workers were selected. To study effects of work-family conflict on reduction of working hours over 12 and 24 months of follow-up, respectively, only day workers (males and females) were selected, capturing 5809 full-time workers (≥36 h/wk) and 1387 part-time workers (<36 h/wk) at baseline. To examine effects of work-family conflict on refraining from overtime work over 12 months of follow-up, only day workers reporting frequent overtime work at baseline were selected (3145 full-time and 492 part-time workers). Cox regression analyses were performed with adjustments for age, educational level, and presence of a long-term illness. Work-family conflict was associated with a significantly increased risk of changing from shift- to day work over 32 months of follow-up in three-shift workers (relative risk [RR] = 1.77, 95% confidence interval [CI] 1.19–2.63) but not in five-shift workers (RR = 1.32, 95% CI 0.78–2.24) and irregular-shift workers (RR = 0.81, 95% CI 0.50–1.31). Within day workers, work-family conflict among full-time workers was associated with a significantly increased risk of reducing working hours during 1 yr of follow-up in women (RR = 2.80, 95% CI 1.42–5.54) but not men (RR = 1.34, 95% CI 0.81–2.22). In part-time workers, work-family conflict was associated with a significantly increased risk of reducing working hours during 1 yr of follow-up both in women (RR = 1.99, 95% CI 1.04–3.82) and men (RR = 4.03, 95% CI 1.28–12.68). Whereas the effects of work-family conflict on a reduction of working hours somewhat decreased among female full-time workers after 2 yr of follow-up (RR = 2.13, 95% CI 1.24–3.66), among male full-time workers the effects increased and reached statistical significance (RR = 1.53, 95% CI 1.05–2.21). Work-family conflict was not significantly associated with refraining from overtime work over 1 yr of follow-up. This study shows that work-family conflict has important consequences in terms of adjustments in work schedules and working hours over time, with considerable sex differences. The study thereby clearly illustrates secondary selection processes both in shift- and day workers, with significant implications for labor force participation, emphasizing the need for prevention of work-family conflict (Author correspondence: Nicole.Jansen@epid.unimaas.nl).

The association between study characteristics and outcome in the relation between job stress and cardiovascular disease – a multilevel meta-regression analysis

OBJECTIVES Studies about job strain and cardiovascular disease (CVD) have yielded inconsistent results, which hinders making a firm conclusion about the association. Inconsistent findings may be the result of methodological differences. If the relative CVD risk is influenced by methodological differences, these differences should be explored in more detail in future research to clarify which methodological characteristics are inherent to obtain the most accurate estimate between job strain and CVD risk. By assessing how study characteristics are associated with the outcome, we take the first step in unraveling this association. In this review, we explore the following research question: are study characteristics associated with the size of the reported relative CVD risk? METHODS A systematic literature search yielded 71 studies about job stress, assessed with the demand-control model, and CVD. Traditional meta-regression was extended enabling the use of correlated data to quantify heterogeneity within and between studies. RESULTS Compared to studies that use the original Job Content Questionnaire (JCQ), studies in which a more deviant form of the JCQ was used yielded, on average, 43% higher estimates. Studies conducted in the USA yielded about 26% lower estimates compared to studies conducted in Scandinavian countries. CONCLUSIONS Several study characteristics are associated with the size of the reported relative CVD risk. Many of these study features are related to the validity of the exposure and outcome assessment and are inherent to obtain an accurate estimate between work stress and CVD risk. More research is needed to clarify why these study features impact the average relative CVD risk.

The Context Dependency of the Self-Report Version of the Strength and Difficulties Questionnaire (SDQ): A Cross-Sectional Study between Two Administration Settings

Background The Strength and Difficulties Questionnaire (SDQ) is a screening instrument for psychosocial problems in children and adolescents, which is applied in “individual” and “collective” settings. Assessment in the individual setting is confidential for clinical applications, such as preventive child healthcare, while assessment in the collective setting is anonymous and applied in (epidemiological) research. Due to administration differences between the settings it remains unclear whether results and conclusions actually can be used interchangeably. This study therefore aims to investigate whether the SDQ is invariant across settings. Methods Two independent samples were retrieved (mean age = 14.07 years), one from an individual setting (N = 6,594) and one from a collective setting (N = 4,613). The SDQ was administered in the second year of secondary school in both settings. Samples come from the same socio-geographic population in the Netherlands. Results Confirmatory factor analysis showed that the SDQ was measurement invariant/equivalent across settings and gender. On average, children in the individual setting scored lower on total difficulties (mean difference = 2.05) and the psychosocial problems subscales compared to those in the collective setting. This was also reflected in the cut-off points for caseness, defined by the 90th percentiles, which were lower in the individual setting. Using cut-off points from the collective in the individual setting therefore resulted in a small number of cases, 2 to 3%, while ∼10% is expected. Conclusion The SDQ has the same connotation across the individual and collective setting. The observed structural differences regarding the mean scores, however, undermine the validity of the cross-use of absolute SDQ-scores between these settings. Applying cut-off scores from the collective setting in the individual setting could, therefore, result in invalid conclusions and potential misuse of the instrument. To correctly apply cut-off scores these should be retrieved from the applied setting.

Immune effects and exposure to ethylenebisdithiocarbamate pesticides in re-entry workers in the Netherlands.

Ethylenebisdithiocarbamates are widely used as fungicides in agriculture. Although EBDC’s have a low acute toxicity, they are suspected to have immune effects at low doses. However, little human studies on these effects have been published. In the Netherlands, a study was conducted among pesticide exposed workers aimed at evaluating the short-term and long-term immune effects of exposure and the relation between ethylenebisdithiocarbamate and immune effects. Forty-one re-entry workers and 40 nonexposed controls were medically examined; furthermore, immune parameters were determined in blood, and all participants filled in a questionnaire regarding exposure and outcome parameters. The level of ethylenethiourea in urine was determined as indicator of exposure. No relevant adverse immune effects were found in the pesticide exposed workers compared with the nonexposed controls. Also no exposure response relationship between immune effects and ethylenebisdithiocarbamate in urine was found. This finding might be due to very low exposure levels of the re-entry work but might also be due to a lack of immunotoxicity of ethylenebisdithiocarbamate at normal exposure levels.

Toepassing van anonieme onderzoeksgegevens over de SDQ binnen de JGZ : Bruikbaarheid en valkuilen

SamenvattingOm psychosociale problemen binnen de jeugdgezondheidszorg (JGZ) tijdig te signaleren bij basis- en middelbare scholieren wordt er tijdens de periodieke gezondheidsonderzoeken (PGO) gebruik gemaakt van de Strengths and Difficulties Questionnaire (SDQ). Voor de ondersteuning van deze vroegsignalering met behulp van de SDQ zijn er afkappunten opgesteld. Deze afkappunten komen voornamelijk voort uit validatiestudies met een anonieme setting. Deze setting verschilt met de vertrouwelijke, niet-anonieme setting van het PGO, waar de professional inzicht krijgt in de vragenlijst. Hierdoor is er dus een discrepantie tussen de setting waarin de SDQ wordt toegepast en waar deze wordt gevalideerd. In deze studie wordt onderzocht of deze discrepantie zorgt voor een verschil in de SDQ met betrekking tot de betrouwbaarheid, gemiddelde scores en afkappunten. Hiervoor worden gegevens gebruikt van de vragenlijsten uit het vertrouwelijke PGO (N = 6.594) en de anonieme Jeugdmonitor (N = 4.613), beide afgenomen in het tweede jaar van het voortgezet onderwijs. De betrouwbaarheid in beide settings is gelijk; de gemiddelde scores en afkappunten verschillen echter significant. Het is dus niet valide om de afkappunten uit de anonieme validatie studies één-op-één te gebruiken in het PGO, dan wel gemiddelde scores tussen deze settings direct met elkaar te vergelijken.AbstractApplication of anonymous research data of the SDQ within the preventive child healthcare: Usefulness and pitfalls. For the early detection of psychosocial problems within the preventive child healthcare (PCH), for children in primary and secondary school, the Strengths and Difficulties Questionnaire (SDQ) is used during assessments. The early detection with the SDQ is facilitated by the use of cut-off points. These cut-off points are in general extracted from validation studies within an anonymous setting. This setting is different from the confidential, non-anonymous, setting of the PCH in which the SDQ questionnaire is reviewed by the health professional. There is, therefore, a discrepancy between the settings in which the SDQ is validated and in which it is implemented. In the present study it is investigated whether this discrepancy creates a difference in the SDQ regarding reliability, mean scores, and cutoff points. For this study questionnaires were used from confidential PCH assessments (N = 6.594) and the anonymous Youthmonitor (N = 4.613), both administered in the second year of secondary school. The reliability of the SDQ was equal in both settings; the mean scores and cut-off points differed however significantly. It is, therefore, not valid to use the cut-off values for the SDQ derived from anonymous settings within confidential settings (e.g. PCH) nor to directly compare the mean scores of these different settings. Keywords: preventive child healthcare, SDQ, early detection, cut-off points, psychosocial behavior

Toepassing van anonieme onderzoeksgegevens over de SDQ binnen de JGZ

SamenvattingOm psychosociale problemen binnen de jeugdgezondheidszorg (JGZ) tijdig te signaleren bij basis- en middelbare scholieren wordt er tijdens de periodieke gezondheidsonderzoeken (PGO) gebruik gemaakt van de Strengths and Difficulties Questionnaire (SDQ). Voor de ondersteuning van deze vroegsignalering met behulp van de SDQ zijn er afkappunten opgesteld. Deze afkappunten komen voornamelijk voort uit validatiestudies met een anonieme setting. Deze setting verschilt met de vertrouwelijke, niet-anonieme setting van het PGO, waar de professional inzicht krijgt in de vragenlijst. Hierdoor is er dus een discrepantie tussen de setting waarin de SDQ wordt toegepast en waar deze wordt gevalideerd. In deze studie wordt onderzocht of deze discrepantie zorgt voor een verschil in de SDQ met betrekking tot de betrouwbaarheid, gemiddelde scores en afkappunten. Hiervoor worden gegevens gebruikt van de vragenlijsten uit het vertrouwelijke PGO (N = 6.594) en de anonieme Jeugdmonitor (N = 4.613), beide afgenomen in het tweede jaar van het voortgezet onderwijs. De betrouwbaarheid in beide settings is gelijk; de gemiddelde scores en afkappunten verschillen echter significant. Het is dus niet valide om de afkappunten uit de anonieme validatie studies een-op-een te gebruiken in het PGO, dan wel gemiddelde scores tussen deze settings direct met elkaar te vergelijken.