Psychosocial factors and psychosomatic complaints among postal workers

The aim with this cross-sectional study of postal workers in7 different occupations was to evaluate the correlations betweensome psychosocial factors and psychosomatic complaints. A sampleof 105 men and 38 women were given self-administered questionnaires.The questionnaires inquired about gastrointestinal complaints,sleep quality, psychological work demands, decision latitude,and social support at the workplace. The data were analysedby variance analysis (Anova), ²-test and stepwise multiple regression.In the group with the lowest psychological work demands, thehighest decision latitude, and the best social support, therewere few symptoms in comparison with the other groups. The findingsare consistent with the hypothesis that a poor psychosocialwork situation results in a higher report of psychosomatic complaints.Therefore, it is important to elucidate the causes of high frequencyof certain symptoms. This would be an important task for theoccupational health service, since psychosomatic symptoms mightbe an early indicator of work related problems.     

Factors contributing to job satisfaction following rehabilitation for musculoskeletal impairments

The study investigates whether changing jobs is related to work-related well-being of people with musculoskeletal impairments. In order to assess this relationship subjects who began new jobs after rehabilitation (N=52) were compared with subjects who returned to their former employment (N=63). Work-related well-being was measured by means of the scales job satisfaction and need to recover after work. After controlling for individual characteristics (gender, age, working hours per week, and pain complaints) and job characteristics (job demands and decision latitude), job satisfaction could be predicted by job change. Recovery need after work was predicted by pain complaints, job demands, and decision latitude, but not by job change.     

Individual and work-related risk factors associated with symptoms of musculoskeletal complaints

Summary Individual and work-related risk factors in the development of occupational musculoskeletal complaints were investigated in a cross-sectional study of 52 female production workers and 34 female office workers. The work tasks of the production workers were considered to generate shoulder muscle loads of low amplitude and high repetitiveness, and the work tasks of the office workers, muscle loads of low amplitude and low repetitiveness. The symptom scores were similar in the two groups, with the highest score for both groups in the shoulder-neck region. Previous pain symptoms were an important risk factor for musculoskeletal pain in all body regions, whereas psychosocial problems at work were a risk factor for complaints in the shoulder-neck region. For the office workers, 27% of the variance in shoulder-neck symptoms was explained by the variance in the parameters previous pain symptoms and psychosocial problems in a multilinear regression model. In three groups of workers with different physical loads on the shoulder muscles the symptom scores for workers without previous pain symptoms and psychosocial problems were related to the physical load. For workers with previous pain symptoms and psychosocial problems, the symptom scores were high and similar for all three groups.     

Definition and assessment of specific occupational demands concerning lifting,pushing, and pulling based on a systematic literature search

Aims: (1) To find a universal strategy for the identification of specific demands of a job or task, focusing on occupations in which there may be an increased risk for health complaints owing to these specific demands. (2) To select reliable and valid tests concerning lifting, pushing, and pulling, which consider the relation between occupational work demands and the assessment of the maximally acceptable load on an individual level.

Methods: Literature search was performed using Medline (1988 to May 2001), Embase (1966 to May 2001), and NIOSHTIC (1971–98).

Results: No universal strategy was found for the definition of specific occupational demands. Therefore a "three step strategy" was formulated for defining specific occupational demands in a job or a task in order to prevent health complaints on an individual level. Many tests were found in the literature concerning lifting, but only a few concerning pushing and pulling. None of the tests concerning pushing, pulling, or lifting considered the relation between work demands and the assessment of the maximally acceptable load on an individual level. Furthermore, none of the tests met the criteria of reliability and prognostic value for musculoskeletal complaints completely. Only for the prognostic value of relative strength capacity tests concerning pushing pulling and lifting, did there appear to be limited proof for the development of musculoskeletal complaints.

Conclusions: In general, for the prevention of work related health complaints, it can be suggested that more attention should be paid to: (1) the definition of specific occupational demands; (2) the assessment of specific occupational demands; and (3) the quality of tests for specific occupational demands.

     

Effect of a general fitness program on musculoskeletal symptoms,clinical status,physiological capacity,and perceived work environment among home care service personnel

The aim of the present controlled study was to evaluate the effect of a general fitness program, performed by an occupational health service, using pre-post assessment for a number of different outcome measures. A total of 160 employees working in the central home care service district of Umeå, Sweden were asked to participate in a program of a 1-year long exercise program. Of the 160 selected, 54 subjects declined to participate and nine subjects were rejected after a medical check up. The remaining 97 subjects participated in a schedule consisting of pre-post medical and physiotherapy examinations, questionnaires concerning sociodemography, musculoskeletal and general health complaints and work environment, physiological tests of cardiovascular fitness, and of strength and endurance of shoulder flexors and knee extensors, and registration of sick leave. The subjects were randomly assigned to an exercise (treatment) or control group. The exercise group trained twice a week for 1 year using a mixed program including exercises for coordination, strength/endurance, and fitness. The test schedule was repeated for both groups after 1 year. The exercise intervention was associated with positive changes in prevalence and intensity of musculoskeletal and psychosomatic complaints, better physiotherapy status (less muscle tightness, better neck mobility, and less tender points), increased shoulder strength and increased coordination in thigh muscles. However, the exercise group reported worse situations post-exercise concerning aspects of their physical and psychosocial work-environment (i.e., concerning ergonomy, influence, appreciation and communication with work manager), which might have been due to stress associated with the exercise situation.     

Associations between neck musculoskeletal complaints and work related factors among public service computer workers in Kaunas

Objectives

Information technologies have been developing very rapidly, also in the case of occupational activities. Epidemiological studies have shown that employees, who work with computers, are more likely to complain of musculoskeletal disorders (MSD). The aim of this study was to evaluate associations between neck MSD and individual and work related factors.

Materials and Methods

The investigation which consisted of two parts — a questionnaire study (using Nordic Musculoskeletal questionnaire and Copenhagen Psychosocial Questionnaire) and a direct observation (to evaluate ergonomic work environment using RULA method) was carried out in three randomly selected public sector companies of Kaunas. The study population consisted of 513 public service office workers.

Results

The survey showed that neck MSDs were very common in the investigated population. The prevalence rate amounted to 65.7%. According to our survey neck MSDs were significantly associated with older age, bigger work experience, high quantitative and cognitive job demands, working for longer than 2 h without taking a break as well as with higher ergonomic risk score. The fully adjusted model working for longer than 2 h without taking a break had the strongest associations with neck complaints.

Conclusion

It was confirmed, that neck MSDs were significantly associated with individual factors as well as conditions of work, therefore, preventive actions against neck complaints should be oriented at psychosocial and ergonomic work environment as well as at individual factors.     

Work-related Musculoskeletal Disorders in Urban Bus Drivers of Hong Kong

Introduction: Work-related musculoskeletal disorders (WMSD) affect workers in many occupations including drivers of large vehicles. Urban bus drivers have been found to have high prevalence rates of back problems in overseas studies. Hong Kong is a densely populated city and has a large number of double-deck buses that constitute a major means of public transportation. The present study aimed at investigating the prevalence and characteristics of WMSD in male and female bus drivers who operate double-deck buses in Hong Kong. Method: Altogether 481 bus drivers (404 males, 77 females) participated in the study that consisted of a questionnaire survey as well as physical assessment. The questionnaire included questions on work, musculoskeletal complaints and perceived occupational risk factors associated with each discomfort. Physical assessment consisted of measurement of lumbar spine mobility, hand grip strength, sit-and-reach test, and observation of standing and sitting postures. Results: The results showed generally the male drivers had longer years of work experience but their daily workloads were similar to the females. On the average drivers worked 9–10 h per day, with 5 days on and 1 day off. Neck, back, shoulder and knee/thigh areas had the highest 12-month prevalence rates ranging from 35% to 60%, and about 90% of the discomfort was related to bus-driving. Occupational factors of prolonged sitting and anthropometric mismatch were perceived to be most related to musculoskeletal discomfort. On physical examination, grip strength was significantly related to neck and shoulder discomfort. Conclusions: The present results showed high prevalence rates of WMSD among bus drivers in Hong Kong which warrants further investigation.     

Musculoskeletal complaints in the Netherlands in relation to age, gender and physically demanding work

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 stratified for age, gender, and type of work demands. For each stratified group prevalence rates (PR) were calculated for complaints of the back, neck, upper and lower extremities. Moreover, prevalence rate differences (PRD) were estimated as an absolute effect 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). Significant 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 findings stress the need for implementation of preventive measures. Special attention towards the susceptible group of female employees, the elderly age groups in particular, seems justified. In order to clarify the combined effects of age and physical work demands on musculoskeletal complaints, additional studies are required. Received: 11 November 1996 / Accepted: 7 March 1997     

Perceived job demands relate to self-reported health complaints

BACKGROUND: Illness and illness behaviour are important problems in the Dutch workforce. Illness has been associated with job demands, with high demands relating to poorer health. It has not been reported whether subjective health complaints relate to job demands. AIMS: To investigate whether perceived (physical and mental) workload and specific job demands are associated with self-reported health complaints. METHODS: Cross-sectional study of a random sample of 983 male employees working in manufacturing industry. Job demands and health complaints were investigated using the self-completed Basic Occupational Health Questionnaire. The relationship between demands and health complaints were studied using logistic regression analysis with health complaints as the outcome variable. RESULTS: The questionnaires of 867 workers (88%) were suitable for analysis. The prevalence of health complaints was high. Physical workload was related to musculoskeletal symptoms. Standing work predicted pain in the legs and thoracic as well as low back pain, while sedentary work predicted low back pain. Heavy lifting predicted low back pain and pain in the extremities. Regular bending predicted low back pain and pain in the legs. Repetitive movements predicted pain in the arms and thoracic as well as low back pain. Mental workload was associated with fatigue and chest pain. Working under time pressure and working behind schedule were not related to self-reported health complaints. CONCLUSIONS: Perceived physical job demands matched with self-reported musculoskeletal complaints, whereas perceived mental job demands were unrelated to specific complaints.     

Are musculoskeletal complaints,related work impairment and desirable adjustments in work age-specific?

Purpose

Musculoskeletal complaints from employees commonly occur and may lead to work impairments. Desirable adjustments in work may differ according to age and the type of complaint. We determined whether the prevalence of musculoskeletal complaints, resulting work impairment and desirable and feasible adjustments in work differs between employees of various age groups at a railway company.

Methods

Employees (n = 2,021) were asked to fill out a questionnaire about musculoskeletal complaints by body regions, the resulting work impairment and the desirable and feasible adjustments in their own work situation. Differences between employees of four age groups (22–35, 36–45, 46–55 and 56–66 years) were tested for significance using the chi-square test.

Results

Musculoskeletal complaints in the neck, arm and at least one other body region were most prevalent in the 46–55-year age group compared with the other age groups. Impairments in work due to the musculoskeletal complaints only differed significantly between age groups for lower back complaints, which occurred most often in the oldest age group. Regarding adjustments in work, proportionally more of the youngest employees with musculoskeletal complaints found it desirable and feasible to switch to another job in the company, whereas proportionally more employees within the oldest age group found it desirable and feasible to work fewer days per week.

Conclusions

Employee age groups differed significantly regarding musculoskeletal complaints, resulting work impairment and desirable adjustments in work. Age-specific preventive measures for musculoskeletal complaints could be useful to keep employees healthy to perform their job until retirement and may reduce the costs associated with absenteeism and health care.     

Psychosocial Work Environment Among Employed Swedish Dairy and Pig Farmworkers

ABSTRACT

The purpose of this study was to investigate the psychosocial work environment for employed dairy and pig farmworkers in southern Sweden and to identify potential risk factors related to the psychosocial work environment for the development of musculoskeletal disorders (MSDs). Thirty-seven workers on 10 dairy farms and 30 workers on 10 pig farms participated in the study. The study was based on a Swedish translation of the short version of the Copenhagen Psychosocial Questionnaire (COPSOQ) for analyses of self-perceived psychosocial work environment and the general Nordic questionnaire for analyses of self-perceived MSDs. In general, the psychosocial work environment was assessed as “good” by both the dairy and pig farmworkers. However, the dairy and pig farmworkers experienced lower work demands, poorer general and mental health, and poorer vitality (physical and mental strength, vigor, and energy) compared to other occupations. Furthermore, the results indicated that the quality of leadership, feedback, and social support at work were poorer at the dairy farms than at the pig farms. No significant risk factors related to the psychosocial work environment were identified for MSDs in “the back” and in the “upper extremities.” This study indicates that the psychosocial work environment for the dairy and pig farmworkers may well be improved in order to promote these workplaces as attractive and healthful. This especially seems to be the case concerning the quality of leadership, feedback, and social support at work for the dairy farmworkers. Furthermore, the present study suggests the probability that physical factors are more likely to lead to MSDs among employed livestock workers than factors related to the psychosocial work environment.     

Factors associated with the ability and willingness to continue working until the age of 65 in construction workers

Objectives

The working population is aging and a shortage of workers is expected in the construction industry. As a consequence, it is considered necessary that construction workers extend their working life. The purpose of this study was to explore factors associated with construction workers’ ability and willingness to continue working until the age of 65.

Methods

In total, 5,610 construction workers that participated in the Netherlands Working Conditions Survey filled out questionnaires on demographics, work-related and health-related factors, and on the ability and willingness to continue working until the age of 65. Logistic regression analyses were applied.

Results

Older workers were more often able, but less willing, to continue working until the age of 65. Frequently using force, lower supervisor support, lower skill discretion, and the occurrence of musculoskeletal complaints were associated with both a lower ability and willingness to continue working. In addition, dangerous work, occasionally using force, working in awkward postures, lack of job autonomy, and reporting emotional exhaustion were associated with a lower ability to continue working, whereas working overtime was associated with a higher ability. Furthermore, low social support from colleagues was associated with a higher willingness.

Conclusion

In addition to physical job demands, psychosocial job characteristics play a significant role in both the ability and willingness to continue working until the age of 65 in construction workers. Moreover, preventing musculoskeletal complaints may support the ability and willingness to continue working, whereas preventing emotional exhaustion is relevant for the ability to continue working.     

A comparative analysis on musculoskeletal disorders between Greek and Dutch nursing personnel

Objective: To analyse cross-cultural differences between Greek and Dutch nursing personnel in association with the risk factors and occurrence and consequences (absenteeism and medical care seeking) of musculoskeletal disorders. Methods: This study was based on questionnaire surveys among 393 nurses and caregivers in nursing homes and homes for the elderly in The Netherlands and among 351 nurses in general hospitals in Athens, Greece. Logistic regression analysis was used to analyse associations between physical and psychosocial workload, need for recovery, perceived general health and (1) the occurrence of musculoskeletal complaints in the past 12 months, (2) chronic complaints during at least 3 months, and (3) complaints which led to sickness absence and medical care seeking. Results: Greek nurses reported significantly more back complaints in the past 12 months (75 vs. 62%) than the Dutch workers, but chronicity (11 vs. 12%) and sickness absence (17 vs. 15%) of these complaints did not differ. Similar differences were observed for neck complaints but not for shoulder complaints. Most Greek nurses with back complaints visited a medical specialist (40%) while Dutch nurses and caregivers sought care through a general practitioner (33%). Multivariate analyses showed that in both countries strenuous back postures (ORs 1.9 and 1.9) and especially a moderate general health (ORs 4.3 and 2.9) were the significant risk factors for back pain. Conclusions: In both countries similar risk factors were associated with the occurrence of low-back pain. Cross-national differences were less important for the risk factors and musculoskeletal complaints than for the consequences of these complaints and for medical care seeking.     

Psychosocial work conditions, perceived stress, perceived muscular tension, and neck/shoulder symptoms among medical secretaries

Purpose

Unfavorable psychosocial working conditions are hypothesized to lead to perceived stress, which, in turn, can be related to an increased risk of development of neck/shoulder symptoms through increased and sustained muscle activation. The aim of the present study was to test this hypothesized process model among medical secretaries, a female-dominated profession characterized by a high amount of visual display unit use and a high prevalence of neck/shoulder symptoms.

Methods

In this cross-sectional study, a questionnaire survey was conducted among medical secretaries (n = 200). The proposed process model was tested using a path model framework.

Results

The results indicate that high work demands were related to high perceived stress, which in turn was related to a high perceived muscle tension and neck/shoulder symptoms. Low influence at work was not related to perceived stress, but was directly related to a high perceived muscle tension.

Conclusions

In general, these cross-sectional results lend tentative support for the hypothesis that adverse psychosocial work conditions (high work demands) may contribute to the development of neck/shoulder symptoms through the mechanism of stress-induced sustained muscular activation. This process model needs to be further tested in longitudinal studies.     

Changes in job stress,musculoskeletal symptoms,and complaints of unfavorable working conditions among nurses after the adoption of a computerized order communication system

Objectives Order communication system (OCS) is a real-time computerized hospital information system that supports communication of orders from the ward users to the service departments. The adoption of an OCS may profoundly alter the service patterns of healthcare workers. As a result, job stress, musculoskeletal symptoms, and complaints of unfavorable working conditions can be expected to increase. This study investigated changes in job stress, musculoskeletal symptoms, and complaints of unfavorable working conditions among nurses after an OCS had been adopted and whether adoption of the system affected the changes.Methods A group of nurses employed in a university hospital in Korea was surveyed 1 month before and 3 months after the OCS had been adopted. We used Karaseks job contents questionnaire (JCQ) to evaluate job stress. The cumulative trauma disorder (CTD) questionnaire was used to assess the presence of musculoskeletal symptoms. The presence of unfavorable working conditions was also assessed. Next, we evaluated whether non-work factors (such as demographic factors and life events) had influence on job stress, musculoskeletal symptoms, and complaints of unfavorable working conditions after adoption of the OCS.Results One hundred thirty nurses from the hospital (51.2%) responded to both surveys. Several JCQ scales were notably altered after OCS adoption; psychological job demand was significantly decreased (P<0.01), although subjective assessment for hazardous conditions was significantly increased (P<0.01). There was a significant increase in back complaints (P<0.05). There was considerable decrease in the number of nurses who complained of increase in work intensity (P<0.05), increase of staying time to deal with remaining duties (P<0.05), and abrupt change of duties (P<0.01). According to the analysis for the associations between non-work factors and significantly changed variables, only two non-work factors, tenure and conflicts with friend(s), showed statistical significance with complaints of increase in work intensity (P<0.05)Conclusions This study suggests that a newly adopted computerized system might have provoked changes in job stress, musculoskeletal symptoms, and the complaints of unfavorable working conditions. It was found that, despite the overall favorable changes, complaints of hazardous conditions and back symptoms increased.     

Risk of health complaints and disabilities among Dutch firefighters

Objectives: The purpose of the present study was threefold: (1) to compare the work demands on firefighters (FFs) and office workers (OWs), (2) to compare the prevalence of health complaints and disabilities in the work situation in these two groups, and (3) to explore the effect of work demands on the risk of health complaints. Methods: Self-reported information was gathered from 1,624 FFs (55% response) and 630 OWs (80% response), at the same fire departments in different regions of the Netherlands, on work demands (sitting, and biomechanically and energetically demanding activities and 24-h shifts), health complaints and disabilities. First, we compared the work demands and prevalence rates of health complaints and related disabilities in the two groups, then we explored the risk of health complaints in workers with high and low exposure to work demands. Results: Compared with office workers, FFs reported: (1) less exposure to sitting and more to biomechanically and energetically demanding activities, (2) more knee (OWs 14% vs FFs 20%) and ankle (3% vs 10%) complaints and disabilities resulting from back complaints (30% vs 47%), and (3) less hypertension (7% vs 5%), stomach (13% vs 7%), heart (6% vs 2%), neck (26% vs 16%), shoulder (16% vs 14%) and arm (14% vs 6%) complaints. A higher risk of subjective fatigue was found in workers highly exposed to energetically demanding activities, and of neck, shoulder and arm complaints in workers highly exposed to sitting. Conclusions: Firefighters reported higher physical demands (with the exception of sitting) than office workers did. The prevalence rate of certain complaints or disabilities among FFs was higher (knee and ankle complaints and disabilities related to back complaints) or lower (hypertension, stomach, heart, neck, shoulder and arm complaints) than among OWs. The results suggest that exposure to highly biomechanically demanding activities might cause an increased risk of knee and ankle complaints and that exposure to highly energetically demanding activities might increase the risk of subjective fatigue.     

Relationships between work-related factors and musculoskeletal health with current and future work ability among male workers

Purpose

The purpose was to increase job-specific knowledge about individual and work-related factors and their relationship with current and future work ability (WA). We studied cross-sectional relationships between mental demands, physical exertion during work, grip strength, musculoskeletal pain in the upper extremities and WA and the relationships between these variables and WA 11 years later.

Methods

We used a dataset of a prospective cohort study (1997–2008) among employees of an engineering plant (n?=?157). The cohort was surveyed by means of tests and written questions on work demands, musculoskeletal health, WA score (WAS; 0–10), and mental and physical WA. Spearman correlation coefficients and logistic regression analysis were used.

Results

Among manual workers, we found weak correlations between grip strength and current and future physical WA. We did not find predictors for future poor WA among the manual workers. Among the office workers, we found that musculoskeletal pain was moderately and negatively related to current WAS and physical WA. More handgrip strength related to better future WAS and physical WA. Musculoskeletal pain (OR 1.67 p?<?0.01) and lower handgrip strength (OR 0.91 p?<?0.05) predicted future poor WA among office workers.

Conclusions

Our results showed cross-sectional and longitudinal relationships between musculoskeletal health and work ability depending on occupation. However, the present implies that predicting work ability in the far future based on health surveillance data is rather difficult. Testing the musculoskeletal system (grip strength) and asking workers’ about their musculoskeletal health seems relevant when monitoring work ability.

     

A cross-sectional study of psychosocial work environment and stress in the Danish symphony orchestras

Purpose

To investigate psychosocial work environment and stress in Danish symphony orchestra musicians.

Methods

This was a cross-sectional questionnaire survey of psychosocial work factors and stress symptoms among 441 musicians in six Danish symphony orchestras. The response rate was 78% (n?=?342). The questions were from COPSOQ (Copenhagen Psychosocial Questionnaire). Mean values of 19 COPSOQ-scales were compared by gender and instrument group. The results for the musicians were compared with results for the general Danish work force (COPSOQ database).

Results

Female musicians reported higher work demands and higher stress symptoms than their male colleagues. Between instrument groups, 2nd violinists seemed to be of particular risk compared with the other instrumental groups in aspects of work pace, work organization, and content, whereas 1st violinists perceived higher emotional stress compared with 2nd violinists. The musicians’ experience of increased work demands as well as deteriorated, work organization and job content, interpersonal relations and leadership, and work-individual interface was significantly associated with increasing stress symptoms. Compared to the general workforce independently of gender, Danish symphony orchestra musicians reported higher emotional demands, lower influence, lower social support, lower sense of community, and lower job satisfaction. However, the musicians reported a higher commitment to the workplace.

Conclusions

The findings indicate a more demanding psychosocial work environment exposure among symphony orchestra musicians than among Danish workers in general. Critical results are the relatively high work demands, low influence, and low social support, females being of higher risk than males.     

Selection related to musculoskeletal complaints among employees.

OBJECTIVES: To (a) describe differences in the outcome of cross sectional and longitudinal analysis on musculoskeletal complaints relative to age and work demands, and (b) to assess the entrance and drop out selection on musculoskeletal complaints among groups of employees relative to age and work demands. METHODS: A study population was selected on the basis of questionnaire data from periodical occupational health surveys of almost 45,000 employees collected between 1982 and 1993. From all companies within this data base that participated twice in company wide surveys four years apart, male employees were selected, and stratified for age and work demands. There were several populations: follow up (participation in both surveys); drop out (participation only in the first survey); entrance (participation only at the second survey); and two cross sectional populations (all participants at each survey). Prevalences of back complaints and turnover rates were analysed. RESULTS: Reported back complaints in the cross sectional analysis declined over the oldest age groups in heavy physical work versus a small increase in the longitudinal analysis. The age group 50-9 and back complaints were identified as predictors at the first survey for not participating at the second survey. Neither age nor work demands at the first survey indicated drop out among those employees with back complaints at the first survey. The effects of entrance selection on estimated prevalences were small. CONCLUSIONS: The results indicate that musculoskeletal disorders lead to selection out of work, affecting the validity of both cross sectional and longitudinal epidemiological studies. In future studies analyses of turnover figures on musculoskeletal complaints relative to work demands and age are recommended.