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.

Objectives: This cross-sectional study was performed in order to elucidate the relationship of musculoskeletal complaints with age, gender and physically demanding work in the Netherlands. Methods: Questionnaire data of male (n 36 756) and female (n 7730) employees, gathered as part of periodical occupational health surveys among active workers in the Netherlands, were strati®ed for age, gender, and type of work demands. For each strati®ed group prevalence rates (PR) were calculated for complaints of the back, neck, upper and lower extremities. Moreover, prevalence rate dierences (PRD) were estimated as an absolute eect measure of exposure to various types of physical work demands, with active employees in mentally demanding work acting as a reference population. Results: Musculoskeletal complaints among workers in physically demanding occupations were found to increase with age for both sexes. For several complaints, substantially higher rates were reported for women than for men, with a relatively high number of complaints observed among the older female workers (around 40% for complaints of back, upper and lower extremities). Signi®cant PRDs were present in particular for employees in heavy physically demanding occupations and in jobs with mixed mental and physical work demands. Conclusions: With the ageing of the workforce in mind, these ®ndings stress the need for implementation of preventive measures. Special attention towards the susceptible group of female employees, the elderly age groups in particular, seems justi®ed. In order to clarify the combined eects of age and physical work demands on musculoskeletal complaints, additional studies are required.

Objectives: Building on Karasek's model of job demands and control (JD-C model), this study examined the effects of job control, quantitative workload, and two occupation specific job demands (physical demands and supervisor demands) on fatigue and job dissatisfaction in Dutch lorry drivers. Methods: From 1181 lorry drivers (adjusted response 63%) self reported information was gathered by questionnaire on the independent variables (job control, quantitative workload, physical demands, and supervisor demands) and the dependent variables (fatigue and job dissatisfaction). Stepwise multiple regression analyses were performed to examine the main effects of job demands and job control and the interaction effect between job control and job demands on fatigue and job dissatisfaction. Results: The inclusion of physical and supervisor demands in the JD-C model explained a significant amount of variance in fatigue (3%) and job dissatisfaction (7%) over and above job control and quantitative workload. Moreover, in accordance with Karasek's interaction hypothesis, job control buffered the positive relation between quantitative workload and job dissatisfaction. Conclusions: Despite methodological limitations, the results suggest that the inclusion of (occupation) specific job control and job demand measures is a fruitful elaboration of the JD-C model. The occupation specific JD-C model gives occupational stress researchers better insight into the relation between the psychosocial work environment and wellbeing. Moreover, the occupation specific JD-C model may give practitioners more concrete and useful information about risk factors in the psychosocial work environment. Therefore, this model may provide points of departure for effective stress reducing interventions at work. I n many sectors of industry, the nature of work has changed considerably over the past decades.1 2 Important changes concern making work more flexibile, the entry of the 24 hour economy, mechanisation, automation, and the appliance of information and communication technology. In general, these changes have resulted in a decreased exposure to physical and chemical agents and an increased exposure to psychosocial risk factors. In the road transport industry, for instance, the entry of the 24 hour economy has been accompanied by an increased demand for just in time deliveries leading to an intensification of the work of lorry drivers.3 Furthermore, the appliance of communication technology has led to a decreased feeling of independence and tighter time schedules for these workers. 4 These changes in the nature of work have gone hand in hand with an increased attention in occupational health research directed at the investigation of the relation between psychosocial work factors and health and wellbeing. Several occupational stress models have been postulated that can serve as a theoretical frame for this category of studies. Without doubt, the most influential and successful is the model of job demands and control (JD-C model) described by Karasek and Theo...

No abstract

Objectives-To examine changes in musculoskeletal complaints over four years in groups of employees relative to age and work demands. Methods-Repeated questionnaire data of male employees in heavy physical work (exposed group, n=7324) and mental work (control group, n=4686), stratified for age (20-9, 30-9, 40-9, 50-9), were analysed. For each employee, data on the occurrence of musculoskeletal complaints from two surveys with a mean interval of around four years were available. Changes in prevalences over the follow up interval were analysed. Proportions of new, recovered, and chronic cases as well as those free of complaints at both surveys were studied. Results-For most complaints, there were significantly greater increases in prevalences in the exposed group compared with the control group over the follow up interval particularly within the group aged 40-9 for back, neck, and several sites of the upper and lower limbs. The 20-9 year age group also had significantly greater changes for several musculoskeletal complaints. Within the oldest age group (50-9) exposure to heavy physical work demands only affected changes in prevalences of neck and upper arm complaints. After four years in the cohort free of complaints at the start of the follow up the group aged 40-9 had the highest prevalence of complaints of the back, neck, and the upper and lower limbs. occupations." Most of these surveys were limited to cross sectional data, offering weak evidence for causality due to uncertainty over the time of exposure and bias by a health related selection of employees.Longitudinal studies are considered to be more appropriate for studying the combined effects of aging and exposure to physical work demands on the development of musculoskeletal complaints, even though these studies also have their specific problems.5 Published data on these kinds of studies are scarce. In a four year follow up study of Tuomi et al,6 an increase from 36% to 50% in prevalence of musculoskeletal diseases was reported among male employees in physically demanding jobs compared with a change from 25% to 38% among those in mentally demanding jobs.These findings, however, were based on only one particular age group, employees aged 45 or older.It might be suggested that several age related factors are responsible for an increased risk of developing musculoskeletal complaints with advancing age for employees in physically demanding occupations: (a) biological changes with age-for example, degenerative changes of the intervertebral discs7; (b) the age related increase in number of years of exposure to harmful work demands;2 8 and (c) a gradual change in the balance between physical workload and physical work capacity as a result of a declining physical work capacity with age not compensated for by adaptations in tasks and working conditions.9 10 With this in mind, differences in the development of musculoskeletal complaints between age groups may be expected over a follow up interval of several years.