Einar de Croon - Academia.edu (original) (raw)

Papers by Einar de Croon

Stress Medicine, 2000

Karasek's Job Demand±Control Model (JD-C Model) assumes that decision latitude (control) moderate... more Karasek's Job Demand±Control Model (JD-C Model) assumes that decision latitude (control) moderates the impact of job demands on health and well-being. It was proposed that lack of evidence for this core`interaction hypothesis' was a consequence of an inadequate conceptualization of decision latitude. Taking this proposition into consideration, we re-evaluated the JD-C Model using a sample of 517 Dutch truck drivers. Regression analyses revealed a signi®cant job demands by job control interaction effect as well as signi®cant main effects of the two independent variables on psychosomatic health complaints. However, the magnitude of the interaction effect was very small. Therefore, it was concluded that the interaction hypothesis was not supported in the present study. Copyright

Occupational Medicine, 2008

Background Within a clinical context e-learning is comparable to traditional approaches of contin... more Background Within a clinical context e-learning is comparable to traditional approaches of continuing medical education (CME). However, the occupational health context differs and until now the effect of postgraduate e-learning among occupational physicians (OPs) has not been evaluated. Aim To evaluate the effect of e-learning on knowledge on mental health issues as compared to lecturebased learning in a CME programme for OPs. Methods Within the context of a postgraduate meeting for 74 OPs, a randomized controlled trial was conducted. Test assessments of knowledge were made before and immediately after an educational session with either e-learning or lecture-based learning. Results In both groups, a significant gain in knowledge on mental health care was found (P , 0.05). However, there was no significant difference between the two educational approaches. Conclusion The effect of e-learning on OPs' mental health care knowledge is comparable to a lecture-based approach. Therefore, e-learning can be beneficial for the CME of OPs.

International Archives of Occupational and Environmental Health, 2001

To develop and validate a short and user-friendly questionnaire measuring psychological job strai... more To develop and validate a short and user-friendly questionnaire measuring psychological job strain in truck drivers. In cooperation with an occupational physician in the Dutch road transport industry we developed items on the basis of face validity and information of existing questionnaires on the subject. These items were pilot-tested, by means of interviews, in 15 truck drivers. Study I examined the factorial structure of the initial 30-item trucker strain monitor (TSM) in a sample of 153 truck drivers. Subsequently, number of items per factor was reduced on the basis of reliability analyses (Cronbach's alpha). Study II examined construct and criterion validity of the TSM in a randomly selected group of 2,000 truck drivers, of whom 1,111 participated (adjusted response = 63%). Additionally, sensitivity and specificity were assessed by examining the ability of the TSM to identify truck drivers with or without self-reported sickness absence in the past 12 months because of psychological complaints. Factor analyses of the initial 30-item TSM revealed a two-factor solution. Item reduction resulted in a six-item work-related fatigue scale and four-item sleeping problems scale with high internal consistency. Results of study II confirmed the internal consistency of the TSM scales and provided support for construct and criterion validity. The composite, work-related fatigue, and sleeping problems scale had a sensitivity of 83%, 80% and 71% respectively, in identifying truck drivers with prior sickness absence because of psychological complaints. Specificity rates were 72%, 73% and 72% respectively. Despite methodological limitations, the results suggest that the TSM is a reliable and valid indicator of psychological job strain in truck drivers. In particular, the composite and work-related fatigue scale identified drivers with prior absenteeism because of psychological complaints, quite accurately. Future longitudinal research in specific sub-groups of truck drivers including both self-reported and objective psychological health measures should evidence whether (1) the distinction between two indicators of psychological job strain is useful, and whether (2) the TSM can be used in screening out truck drivers at risk of developing psychological health problems.

Ergonomics, 2005

Conventional and innovative office concepts can be described according to three dimensions: (1) t... more Conventional and innovative office concepts can be described according to three dimensions: (1) the office location (e.g. telework office versus conventional office); (2) the office layout (e.g. open layout versus cellular office); and (3) the office use (e.g. fixed versus shared workplaces). This review examined how these three office dimensions affect the office worker's job demands, job resources, short-and long-term reactions. Using search terms related to the office concept (dimensions), a systematic literature search starting from 1972 was conducted in seven databases. Subsequently, based on the quality of the studies and the consistency of the findings, the level of evidence for the observed findings was assessed. Out of 1091 hits 49 relevant studies were identified. Results provide strong evidence that working in open workplaces reduces privacy and job satisfaction. Limited evidence is available that working in open workplaces intensifies cognitive workload and worsens interpersonal relations; close distance between workstations intensifies cognitive workload and reduces privacy; and desk-sharing improves communication. Due to a lack of studies no evidence was obtained for an effect of the three office dimensions on long-term reactions. The results suggest that ergonomists involved in office innovation could play a meaningful role in safeguarding the worker's job demands, job resources and well-being. Attention should be paid, in particular, to effects of workplace openness by providing acoustic and visual protection.

Applied Ergonomics, 2004

A quasi-experimental design was used to study the effect of on board computer-systems (OBC-system... more A quasi-experimental design was used to study the effect of on board computer-systems (OBC-systems) on the Dutch lorry drivers' psychosocial work environment (i.e., control and demands) and coinciding mental health (i.e., need for recovery after work) and job attitudes (i.e., organisational commitment). The intervention group (n ¼ 26) started working with an OBC-system between 1998 and 2000 and was compared with two matched reference groups (n ¼ 26 in both groups). All participants were from a cohort of 650 drivers who participated in a prospective study on occupational stress and health. All outcome variables were quantified by standardised and validated questionnaires. Results showed that the application of OBC-systems negatively affected the drivers' job control and organisational commitment. However, OBC-systems did not influence the drivers' psychological job demands and need for recovery after work. Accordingly, it is concluded that the application of OBC-systems negatively affects the lorry driver's psychosocial work environment and job attitudes.

Journal of Applied Psychology, 2004

Based on a model that combines existing organizational stress theory and job transition theory, t... more Based on a model that combines existing organizational stress theory and job transition theory, this 2-year longitudinal study examined antecedents and consequences of turnover among Dutch truck drivers. For this purpose, self-reported data on stressful work (job demands and control), psychological strain (need for recovery after work and fatigue), and turnover were obtained from 820 drivers in 1998 and 2000. In agreement with the model, the results showed that strain mediates the influence of stressful work on voluntary turnover. Also in conformity with the model, job movement to any job outside the trucking industry (i.e., interoccupational turnover) resulted in a larger strain reduction as compared to job movement within the trucking industry (intraoccupational turnover). Finally, strain was found to stimulate interoccupational turnover more strongly than it stimulated intraoccupational turnover. These findings provide a thorough validation of existing turnover theory and give new insights into the turnover (decision) process.

TBV – Tijdschrift voor Bedrijfs- en Verzekeringsgeneeskunde, 2005

Occupational and environmental medicine, 2006

Monitoring worker health and evaluating occupational healthcare interventions requires sensitive ... more Monitoring worker health and evaluating occupational healthcare interventions requires sensitive instruments that are reliable over time. The Need for Recovery scale (NFR), which quantifies workers' difficulties in recovering from work related exertions, may be a relevant instrument in this respect. To examine (1) the NFR's test-retest reliability and (2) the NFR's sensitivity to detect the effect of a fatigue inducing change, namely an increase in working hours. Two year longitudinal data of 526 truck drivers and 144 nurses were used. Two week, one year, and two year test-retest reliability was examined in both stable and unstable work environments by calculating intraclass correlations (ICCs). Work environmental (in)stability was quantified by four events that might have occurred during the follow up period: (1) a reorganisation or merge (0 = yes, 1 = no), (2) a change of supervisor or management (0 = yes, 1 = no), (3) a change in working hours or work schedules (0 = y...

Occupational and Environmental Medicine, 2006

Journal of Psychosomatic Research, 2003

Incomplete recovery from work-related fatigue after work (i.e., sustained activation) is assumed ... more Incomplete recovery from work-related fatigue after work (i.e., sustained activation) is assumed to mediate the relation between the exposure to stressful working conditions and the development of health problems. The need for recovery after work scale reflects the extent to which workers have difficulties to recover adequately from work-related fatigue after a working day. The aim of this study was to establish if need for recovery after work in truck drivers (1). predicts future sickness absence (>14 working days) and (2). mediates the prospective relation between stressful working conditions (low control, high job demands) and sickness absence. Self-administered questionnaires, providing information about need for recovery after work, sickness absence, job control, and job demands (psychological, physical, and supervisor job demands), were sent to a random sample of 2000 drivers in 1998. Of the 1123 responders, 820 returned a completed questionnaire 2 years later (response 72%). This study was restricted to the 526 participants who still worked at follow-up as a truck driver at the same company. High baseline need for recovery after work was associated with an increased risk for subsequent sickness absence (odds ratio [OR] 2.19, 95% confidence interval [CI] 1.13-4.24) after adjustment for age, previous sickness absence, marital status, educational level, and company size. Additional adjustment for baseline stressful working conditions led to a marginally reduction of the excess risk for sickness absence. High need for recovery after work increases the risk of subsequent sickness absence that is not explained by relevant (non-) work-related factors. However, the results did not testify that need for recovery after work mediates between the exposure to stressful working conditions, and the subsequent occurrence of sickness absence. Practically, the results indicate that monitoring recovery complaints in truck drivers may assist practitioners to take efficient preventive measures at the appropriate time.

… environmental health, 2005

Background: Monitoring psychological job strain may help occupational physicians to take preventi... more Background: Monitoring psychological job strain may help occupational physicians to take preventive action at the appropriate time. For this purpose, the 10-item trucker strain monitor (TSM) assessing work-related fatigue and sleeping problems in truck drivers was ...

Stress Medicine, 2000

Karasek's Job Demand±Control Model (JD-C Model) assumes that decision latitude (control) moderate... more Karasek's Job Demand±Control Model (JD-C Model) assumes that decision latitude (control) moderates the impact of job demands on health and well-being. It was proposed that lack of evidence for this core`interaction hypothesis' was a consequence of an inadequate conceptualization of decision latitude. Taking this proposition into consideration, we re-evaluated the JD-C Model using a sample of 517 Dutch truck drivers. Regression analyses revealed a signi®cant job demands by job control interaction effect as well as signi®cant main effects of the two independent variables on psychosomatic health complaints. However, the magnitude of the interaction effect was very small. Therefore, it was concluded that the interaction hypothesis was not supported in the present study. Copyright

Occupational Medicine, 2008

Background Within a clinical context e-learning is comparable to traditional approaches of contin... more Background Within a clinical context e-learning is comparable to traditional approaches of continuing medical education (CME). However, the occupational health context differs and until now the effect of postgraduate e-learning among occupational physicians (OPs) has not been evaluated. Aim To evaluate the effect of e-learning on knowledge on mental health issues as compared to lecturebased learning in a CME programme for OPs. Methods Within the context of a postgraduate meeting for 74 OPs, a randomized controlled trial was conducted. Test assessments of knowledge were made before and immediately after an educational session with either e-learning or lecture-based learning. Results In both groups, a significant gain in knowledge on mental health care was found (P , 0.05). However, there was no significant difference between the two educational approaches. Conclusion The effect of e-learning on OPs' mental health care knowledge is comparable to a lecture-based approach. Therefore, e-learning can be beneficial for the CME of OPs.

International Archives of Occupational and Environmental Health, 2001

To develop and validate a short and user-friendly questionnaire measuring psychological job strai... more To develop and validate a short and user-friendly questionnaire measuring psychological job strain in truck drivers. In cooperation with an occupational physician in the Dutch road transport industry we developed items on the basis of face validity and information of existing questionnaires on the subject. These items were pilot-tested, by means of interviews, in 15 truck drivers. Study I examined the factorial structure of the initial 30-item trucker strain monitor (TSM) in a sample of 153 truck drivers. Subsequently, number of items per factor was reduced on the basis of reliability analyses (Cronbach's alpha). Study II examined construct and criterion validity of the TSM in a randomly selected group of 2,000 truck drivers, of whom 1,111 participated (adjusted response = 63%). Additionally, sensitivity and specificity were assessed by examining the ability of the TSM to identify truck drivers with or without self-reported sickness absence in the past 12 months because of psychological complaints. Factor analyses of the initial 30-item TSM revealed a two-factor solution. Item reduction resulted in a six-item work-related fatigue scale and four-item sleeping problems scale with high internal consistency. Results of study II confirmed the internal consistency of the TSM scales and provided support for construct and criterion validity. The composite, work-related fatigue, and sleeping problems scale had a sensitivity of 83%, 80% and 71% respectively, in identifying truck drivers with prior sickness absence because of psychological complaints. Specificity rates were 72%, 73% and 72% respectively. Despite methodological limitations, the results suggest that the TSM is a reliable and valid indicator of psychological job strain in truck drivers. In particular, the composite and work-related fatigue scale identified drivers with prior absenteeism because of psychological complaints, quite accurately. Future longitudinal research in specific sub-groups of truck drivers including both self-reported and objective psychological health measures should evidence whether (1) the distinction between two indicators of psychological job strain is useful, and whether (2) the TSM can be used in screening out truck drivers at risk of developing psychological health problems.

Ergonomics, 2005

Conventional and innovative office concepts can be described according to three dimensions: (1) t... more Conventional and innovative office concepts can be described according to three dimensions: (1) the office location (e.g. telework office versus conventional office); (2) the office layout (e.g. open layout versus cellular office); and (3) the office use (e.g. fixed versus shared workplaces). This review examined how these three office dimensions affect the office worker's job demands, job resources, short-and long-term reactions. Using search terms related to the office concept (dimensions), a systematic literature search starting from 1972 was conducted in seven databases. Subsequently, based on the quality of the studies and the consistency of the findings, the level of evidence for the observed findings was assessed. Out of 1091 hits 49 relevant studies were identified. Results provide strong evidence that working in open workplaces reduces privacy and job satisfaction. Limited evidence is available that working in open workplaces intensifies cognitive workload and worsens interpersonal relations; close distance between workstations intensifies cognitive workload and reduces privacy; and desk-sharing improves communication. Due to a lack of studies no evidence was obtained for an effect of the three office dimensions on long-term reactions. The results suggest that ergonomists involved in office innovation could play a meaningful role in safeguarding the worker's job demands, job resources and well-being. Attention should be paid, in particular, to effects of workplace openness by providing acoustic and visual protection.

Applied Ergonomics, 2004

A quasi-experimental design was used to study the effect of on board computer-systems (OBC-system... more A quasi-experimental design was used to study the effect of on board computer-systems (OBC-systems) on the Dutch lorry drivers' psychosocial work environment (i.e., control and demands) and coinciding mental health (i.e., need for recovery after work) and job attitudes (i.e., organisational commitment). The intervention group (n ¼ 26) started working with an OBC-system between 1998 and 2000 and was compared with two matched reference groups (n ¼ 26 in both groups). All participants were from a cohort of 650 drivers who participated in a prospective study on occupational stress and health. All outcome variables were quantified by standardised and validated questionnaires. Results showed that the application of OBC-systems negatively affected the drivers' job control and organisational commitment. However, OBC-systems did not influence the drivers' psychological job demands and need for recovery after work. Accordingly, it is concluded that the application of OBC-systems negatively affects the lorry driver's psychosocial work environment and job attitudes.

Journal of Applied Psychology, 2004

Based on a model that combines existing organizational stress theory and job transition theory, t... more Based on a model that combines existing organizational stress theory and job transition theory, this 2-year longitudinal study examined antecedents and consequences of turnover among Dutch truck drivers. For this purpose, self-reported data on stressful work (job demands and control), psychological strain (need for recovery after work and fatigue), and turnover were obtained from 820 drivers in 1998 and 2000. In agreement with the model, the results showed that strain mediates the influence of stressful work on voluntary turnover. Also in conformity with the model, job movement to any job outside the trucking industry (i.e., interoccupational turnover) resulted in a larger strain reduction as compared to job movement within the trucking industry (intraoccupational turnover). Finally, strain was found to stimulate interoccupational turnover more strongly than it stimulated intraoccupational turnover. These findings provide a thorough validation of existing turnover theory and give new insights into the turnover (decision) process.

TBV – Tijdschrift voor Bedrijfs- en Verzekeringsgeneeskunde, 2005

Occupational and environmental medicine, 2006

Monitoring worker health and evaluating occupational healthcare interventions requires sensitive ... more Monitoring worker health and evaluating occupational healthcare interventions requires sensitive instruments that are reliable over time. The Need for Recovery scale (NFR), which quantifies workers' difficulties in recovering from work related exertions, may be a relevant instrument in this respect. To examine (1) the NFR's test-retest reliability and (2) the NFR's sensitivity to detect the effect of a fatigue inducing change, namely an increase in working hours. Two year longitudinal data of 526 truck drivers and 144 nurses were used. Two week, one year, and two year test-retest reliability was examined in both stable and unstable work environments by calculating intraclass correlations (ICCs). Work environmental (in)stability was quantified by four events that might have occurred during the follow up period: (1) a reorganisation or merge (0 = yes, 1 = no), (2) a change of supervisor or management (0 = yes, 1 = no), (3) a change in working hours or work schedules (0 = y...

Occupational and Environmental Medicine, 2006

Journal of Psychosomatic Research, 2003

Incomplete recovery from work-related fatigue after work (i.e., sustained activation) is assumed ... more Incomplete recovery from work-related fatigue after work (i.e., sustained activation) is assumed to mediate the relation between the exposure to stressful working conditions and the development of health problems. The need for recovery after work scale reflects the extent to which workers have difficulties to recover adequately from work-related fatigue after a working day. The aim of this study was to establish if need for recovery after work in truck drivers (1). predicts future sickness absence (>14 working days) and (2). mediates the prospective relation between stressful working conditions (low control, high job demands) and sickness absence. Self-administered questionnaires, providing information about need for recovery after work, sickness absence, job control, and job demands (psychological, physical, and supervisor job demands), were sent to a random sample of 2000 drivers in 1998. Of the 1123 responders, 820 returned a completed questionnaire 2 years later (response 72%). This study was restricted to the 526 participants who still worked at follow-up as a truck driver at the same company. High baseline need for recovery after work was associated with an increased risk for subsequent sickness absence (odds ratio [OR] 2.19, 95% confidence interval [CI] 1.13-4.24) after adjustment for age, previous sickness absence, marital status, educational level, and company size. Additional adjustment for baseline stressful working conditions led to a marginally reduction of the excess risk for sickness absence. High need for recovery after work increases the risk of subsequent sickness absence that is not explained by relevant (non-) work-related factors. However, the results did not testify that need for recovery after work mediates between the exposure to stressful working conditions, and the subsequent occurrence of sickness absence. Practically, the results indicate that monitoring recovery complaints in truck drivers may assist practitioners to take efficient preventive measures at the appropriate time.

… environmental health, 2005

Background: Monitoring psychological job strain may help occupational physicians to take preventi... more Background: Monitoring psychological job strain may help occupational physicians to take preventive action at the appropriate time. For this purpose, the 10-item trucker strain monitor (TSM) assessing work-related fatigue and sleeping problems in truck drivers was ...