Experiences with multiple job holding: a qualitative study among Dutch older workers.

BACKGROUND: Multiple job holding (MJH) is a common and growing phenomenon in many countries. Little is known about experiences with MJH among older workers. The objective of the present study is to gain insight in experiences with MJH among Dutch workers aged 45 years and older. METHODS: Multiple job holders were selected from the Study on Transitions in Employment, Ability, and Motivation (STREAM), a Dutch cohort study among persons aged 45 years and older. Purposive sampling was applied to assure heterogeneity regarding gender, educational level, health, financial situation, willingness to continue MJH, and type of MJH (only jobs as employee or also being self-employed). Interviews were conducted until data saturation occurred. Fifteen multiple job holders participated in this study (eight men, seven women). Interviews were digitally recorded, transcribed verbatim and analyzed, along with field notes, using thematic content analysis. The data were openly coded, after which codes were aggregated into themes, which formed a thematic map. In each phase of the analysis at least two researchers were involved to increase reliability. RESULTS: Experiences with MJH varied from positive to negative. They were influenced by characteristics of individual jobs, e.g. social support at work, as well as characteristics of the combination of jobs, e.g. positive spill-over effects, and conflicts between work schedules. The personal context of multiple job holders, e.g. their age, or reason for MJH, affected how work characteristics influenced experiences. Negative experiences with one job often coincided with negative experience in the other job(s), and problems in the personal context. Some multiple job holders were able to make changes to their situation when desired. For some, this was not possible, which augmented their negative experience. CONCLUSIONS: This study adds to existing knowledge that experiences with MJH are not only influenced by work characteristics but also by the personal context of multiple job holders, and that some workers are able to change their situation when desired, while others are not. Future research should study how different combinations of work and personal characteristics influence sustainable employability of multiple job holders. Policies facilitating life-long learning could increase opportunities to change the MJH situation when desired.

The cost-effectiveness and return-on-investment of a combined social and physical environmental intervention in office employees.

This study explored the cost-effectiveness and return-on-investment of a combined social and physical environmental worksite health promotion program compared with usual practice, and of both intervention conditions separately. Participants were randomized to the combined intervention (n = 92), social environmental intervention (n = 118), physical environmental intervention (n = 96), or control group (n = 106). The social environmental intervention consisted of group motivational interviewing and the physical environmental intervention of workplace modifications. Both interventions were aimed at improving physical activity and relaxation. Effects included need for recovery (NFR), general vitality and job satisfaction. Cost-effectiveness analyses were performed from the societal and employer's perspective, and return-on-investment analyses from the employer's perspective. Compared with usual practice, the combined intervention was significantly more effective in improving NFR (-8.4;95% CI:-14.6;-2.2) and significantly more expensive to the employer (3102; 95%CI:598;5969). All other between-group differences were non-significant. For NFR, the combined intervention became the preferred option at willingness-to-pays of ≥€170/point improvement (society) and ≥€300/point improvement (employer). For general vitality and job satisfaction, the interventions' maximum probabilities of cost-effective were low (≤0.55). All interventions had a negative return-on-investment. The combined intervention may be cost-effective for NFR depending on the decision-makers' willingness-to-pay. Both separate interventions are not cost-effective for NFR. All interventions were neither cost-effective for general vitality and job satisfaction, nor cost-saving to the employer.

Prevention program at construction worksites aimed at improving health and work ability is cost-saving to the employer: results from an RCT.

BACKGROUND: To prolong sustainable healthy working lives of construction workers, a prevention program was developed which aimed to improve the health and work ability of construction workers. The objective of this study was to analyze the cost-effectiveness and financial return from the employers' perspective of this program. METHODS: A total of 293 workers in 15 departments were randomized to the intervention (n = 8 departments) or control group (n = 7). Data on work ability and health were collected using questionnaires. Sick leave data were obtained from the companies. Both the cost-effectiveness analyses and return on investment analyses were performed. RESULTS: After 12 months, the absenteeism costs were significantly lower in the intervention group than in the control group. At 12-month follow-up, no significant differences were found with respect to the primary outcomes (work ability, mental and physical health status) and secondary outcomes (musculoskeletal symptoms), meaning that the intervention was not cost-effective in comparison with the control group. The net-benefit was €641 per worker, and the intervention generated a positive financial return to the employer. CONCLUSION: The intervention in the present study was cost-saving to the employer due to reduced sickness absenteeism costs in the intervention group compared with the control group. However, the intervention cannot be regarded as cost-effective as no significant effects were found for work ability and health.

Internal consistency, test-retest reliability and concurrent validity of a questionnaire on work-related exposure related to arm, shoulder and neck symptoms in computer workers.

The aim of this study was to determine the internal consistency, test-retest reliability and concurrent validity of the RSI QuickScan, a newly developed questionnaire that aims to identify the presumed risk factors for neck, shoulder and arm symptoms in a population of computer workers. The internal consistency was calculated using item analysis. The test-retest reliability and concurrent validity were analysed by calculating the percentage of agreement, Cohen's Kappa and the Ppositive and Pnegative. The concurrent validity was also tested by comparing the results from the new questionnaire with those from the original questionnaires that the current questionnaire was based on, on-site expert observations and direct measurements. The results indicate that the RSI QuickScan is a measurement tool with acceptable internal consistency, reliability and concurrent validity. The questionnaire can be used as a means to rapidly collect data on a large population of office workers and at low cost.

Should office workers spend fewer hours at their computer? A systematic review of the literature.

Worldwide, millions of office workers use a computer. Reports of adverse health effects due to computer use have received considerable media attention. This systematic review summarises the evidence for a relationship between the duration of work time spent using the computer and the incidence of hand-arm and neck-shoulder symptoms and disorders. Several databases were systematically searched up to 6 November 2005. Two reviewers independently selected articles that presented a risk estimate for the duration of computer use, included an outcome measure related to hand-arm or neck-shoulder symptoms or disorders, and had a longitudinal study design. The strength of the evidence was based on methodological quality and consistency of the results. Nine relevant articles were identified, of which six were rated as high quality. Moderate evidence was concluded for a positive association between the duration of mouse use and hand-arm symptoms. For this association, indications for a dose-response relationship were found. Risk estimates were in general stronger for the hand-arm region than for the neck-shoulder region, and stronger for mouse use than for total computer use and keyboard use. A pathophysiological model focusing on the overuse of muscles during computer use supports these differences. Future studies are needed to improve our understanding of safe levels of computer use by measuring the duration of computer use in a more objective way, differentiating between total computer use, mouse use and keyboard use, attaining sufficient exposure contrast, and collecting data on disability caused by symptoms.

Can strenuous leisure time physical activity prevent psychological complaints in a working population?

AIMS: To investigate the longitudinal relation between strenuous leisure time physical activity and psychological complaints (depression and emotional exhaustion) in a Dutch working population in order to find evidence for the preventive role of physical activity in the development of psychological complaints. METHODS: All data came from the Study on Musculoskeletal disorders, Absenteeism, Stress, and Health (SMASH), a three year follow up study that started between 1994 and 1995. The study population consisted of 1747 workers from 34 companies. Generalised estimating equation (GEE) analyses were performed to investigate the longitudinal relation between strenuous leisure time physical activity and psychological complaints using models with and without a time lag. Logistic regression analyses were performed to study the relation between physical activity and sickness absence due to psychological complaints during the three year follow up study. RESULTS: Only in workers with a sedentary job was strenuous leisure time physical activity (1-2 times per week) significantly associated with a reduced risk of future depression and emotional exhaustion. This was not the case for physical activity at higher frequencies (> or =3 times per week). There was a dose-response relation between strenuous leisure time physical activity and poor general health which was strongest in workers with a sedentary job. Strenuous leisure time physical activity (1-2 times per week) was associated with a lower risk of long term absenteeism (>21 days), whereas physical activity at a higher frequency was not. CONCLUSIONS: Results suggest that strenuous leisure time physical activity might play a role in the prevention of future psychological complaints, poor general health, and long term absenteeism in a working population. Workers with a sedentary job seem to benefit more from strenuous leisure time physical activity than workers without a sedentary job.

The effectiveness of graded activity for low back pain in occupational healthcare.

BACKGROUND: Low back pain is a common medical and social problem associated with disability and absence from work. Knowledge on effective return to work (RTW) interventions is scarce. OBJECTIVE: To determine the effectiveness of graded activity as part of a multistage RTW programme. DESIGN: Randomised controlled trial. SETTING: Occupational healthcare. SUBJECTS: 112 workers absent from work for more than eight weeks due to low back pain were randomised to either graded activity (n = 55) or usual care (n = 57). INTERVENTION: Graded activity, a physical exercise programme aimed at RTW based on operant-conditioning behavioural principles. MAIN OUTCOME MEASURES: The number of days off work until first RTW for more then 28 days, total number of days on sick leave during follow up, functional status, and severity of pain. Follow up was 26 weeks. RESULTS: Graded activity prolonged RTW. Median time until RTW was equal to the total number of days on sick leave and was 139 (IQR = 69) days in the graded activity group and 111 (IQR = 76) days in the usual care group (hazard ratio = 0.52, 95% CI 0.32 to 0.86). An interaction between a prior workplace intervention and graded activity, together with a delay in the start of the graded activity intervention, explained most of the delay in RTW (hazard ratio = 0.86, 95% CI 0.40 to 1.84 without prior intervention and 0.39, 95% CI 0.19 to 0.81 with prior intervention). Graded activity did not improve pain or functional status clinically significantly. CONCLUSIONS: Graded activity was not effective for any of the outcome measures. Different interventions combined can lead to a delay in RTW. Delay in referral to graded activity delays RTW. In implementing graded activity special attention should be paid to the structure and process of care.

Physical capacity in relation to low back, neck, or shoulder pain in a working population.

AIMS: To investigate the longitudinal relation between physical capacity (isokinetic lifting strength, static endurance of the back, neck, and shoulder muscles, and mobility of the spine) and low back, neck, and shoulder pain. METHODS: In this prospective cohort study, 1789 Dutch workers participated. At baseline, isokinetic lifting strength, static endurance of the back, neck, and shoulder muscles, and mobility of the spine were measured in the pain free workers, as well as potential confounders, including physical workload. Low back, neck, and shoulder pain were self-reported annually at baseline and three times during follow up. RESULTS: After adjustment for confounders, Poisson generalised estimation equations showed an increased risk of low back pain among workers in the lowest sex specific tertile of performance in the static back endurance tests compared to workers in the reference category (RR = 1.42; 95% CI 1.19 to 1.71), but this was not found for isokinetic trunk lifting strength or mobility of the spine. An increased risk of neck pain was shown for workers with low performance in tests of isokinetic neck/shoulder lifting strength (RR = 1.31; 95% CI 1.03 to 1.67) and static neck endurance (RR = 1.22; 95% CI 1.00 to 1.49). Among workers in the lowest tertiles of isokinetic neck/shoulder lifting strength or endurance of the shoulder muscles, no increased risk of shoulder pain was found. CONCLUSIONS: The findings of this study suggest that low back or neck endurance were independent predictors of low back or neck pain, respectively, and that low lifting neck/shoulder strength was an independent predictor of neck pain. No association was found between lifting trunk strength, or mobility of the spine and the risk of low back pain, nor between lifting neck/shoulder strength or endurance of the shoulder muscles and the risk of shoulder pain.

Prognostic factors for duration of sick leave in patients sick listed with acute low back pain: a systematic review of the literature.

BACKGROUND: The percentages of patients with acute low back pain (LBP) that go on to a chronic state varies between studies from 2% to 34%. In some of these cases low back pain leads to great costs. AIMS: To evaluate the evidence for prognostic factors for return to work among workers sick listed with acute LBP. METHODS: Systematic literature search with a quality assessment of studies, assessment of levels of evidence for all factors, and pooling of effect sizes. RESULTS: Inclusion of studies in the review was restricted to inception cohort studies of workers with LBP on sick leave for less than six weeks, with the outcome measured in absolute terms, relative terms, survival curve, or duration of sick leave. Of the studies, 18 publications (14 cohorts) fulfilled all inclusion criteria. One low quality study, four moderate quality studies, and nine high quality studies were identified; 79 prognostic factors were studied and grouped in eight categories for which the evidence was assessed. CONCLUSIONS: Specific LBP, higher disability levels, older age, female gender, more social dysfunction and more social isolation, heavier work, and receiving higher compensation were identified as predictors for a longer duration of sick leave. A history of LBP, job satisfaction, educational level, marital status, number of dependants, smoking, working more than 8 hour shifts, occupation, and size of industry or company do not influence duration of sick leave due to LBP. Many different constructs were measured to identify psychosocial predictors of long term sick leave, which made it impossible to determine the role of these factors.

Effect of sporting activity on absenteeism in a working population.

OBJECTIVES: To determine the effects of sporting activity on absenteeism in a working population. METHODS: Data were used from a prospective cohort study in a working population with a follow up period of 3 years and were collected with yearly questionnaires or collected from company records. Complete data on absenteeism, sporting activity, and potential confounders were collected for 1228 workers. ANOVA was used to test differences in frequency and duration of absenteeism, correlations were computed to measure the association between number of sporting years (divided by age) and frequency and duration of absenteeism, and survival analysis, according to the Cox proportional hazards model, was used to test differences in relative risk at absenteeism and recovery. All analyses were adjusted for age, gender, smoking, and alcohol consumption, and were stratified for employees with sedentary and with more active jobs. RESULTS: ANOVA showed a statistically significant higher mean duration of absenteeism among employees not practicing sports, of approximately 20 days over a period of 4 years. The survival analysis showed an increased relative risk at absenteeism (relative risk (RR) 1.09; confidence interval (CI) 1.01 to 1.18) and a decreased relative risk at recovery (RR 0.90; CI 0.85 to 0.95) for employees not practicing sports. The effect of sporting activity is larger in employees with sedentary work. No associations were found between number of sporting years and absenteeism. CONCLUSION: Employees practicing sports take sick leave significantly less often than their colleagues not practicing sports, while their periods of sick leave are shorter, especially when their work is sedentary.

A comparison of methods for the assessment of postural load and duration of computer use.

AIM: To compare two different methods for assessment of postural load and duration of computer use in office workers. METHODS: The study population existed of 87 computer workers. Questionnaire data about exposure were compared with exposures measured by a standardised or objective method. Measuring true exposure to postural load consisted of an observation of the workstation design and posture by a trained observer. A software program was used to record individual computer use. RESULTS: Comparing the answers for each item of postural load, six of eleven items showed low agreement (kappa <0.20). For six items the sensitivity was below 50%, while for eight items the specificity was 80% or higher. Computer workers were unable to identify risk factors in their workplace and work posture. On average, computer workers overestimated their total computer use by 1.6 hours. The agreement among employees who reported a maximum of three hours of computer use per day was higher than the agreement among employees with a high duration of computer use. CONCLUSIONS: Self-report by means of this questionnaire is not a very reliable method to measure postural load and duration of computer use. This study emphasises that the challenge to develop quick and inexpensive techniques for assessing exposure to postural load and duration of computer use is still open.

Self-reported back pain in fork-lift truck and freight-container tractor drivers exposed to whole-body vibration.

To study the long-term health effect of whole-body vibration, a questionnaire on symptoms of ill health was mailed to 242 drivers and a reference group of 210 workers from six harbor companies (response 81%). Vehicles driven were fork-lift trucks and freight-container tractors. Vibration level during a representative working period (vector sum of the frequency weighted acceleration in the x-, y-, and z-directions) was 0.8 m/sec2 for the fork-lift trucks and 1.0 m/sec2 for the freight-container tractors. Only the results concerning self-reported symptoms of the back are described. Of the young (less than 35 years), short-term-exposed drivers, 68% reported that they had back pain regularly vs. only 25% of the reference group of comparable age. With increasing age, the difference in the prevalence of self-reported regular back pain between the drivers and the reference group disappeared. Driving during the 5 years preceding the onset of symptoms seemed to increase the risk of back pain, whereas earlier exposure did not.

Systematic review of psychosocial factors at work and private life as risk factors for back pain.

STUDY DESIGN: A systematic review of observational studies. OBJECTIVES: To assess whether psychosocial factors at work and in private life are risk factors for the occurrence of back pain. SUMMARY OF BACKGROUND DATA: Several reviews on risk factors for back pain have paid attention to psychosocial factors. However, in none of the published reviews was a strict systematic approach used to identify and summarize the available evidence. METHODS: A computerized bibliographical search of several databases was performed, restricted to studies with a cohort or case-control design. A rating system was used to assess the strength of the evidence for various factors, based on the methodologic quality of the studies and the consistency of the findings. RESULTS: Eleven cohort and two case-control studies were included in this review. Strong evidence was found for low social support in the workplace and low job satisfaction as risk factors for back pain. Insufficient evidence was found for an effect of a high work pace, high qualitative demands, low job content, low job control, and psychosocial factors in private life. CONCLUSIONS: Evidence was found for an effect of low workplace social support and low job satisfaction. However, the result for workplace social support was sensitive to slight changes in the rating system, and the effect found for low job satisfaction may be a result of insufficient adjustment for psychosocial work characteristics and physical load at work. In addition, the combined evaluation of job content and job control, both aspects of decision latitude, led to strong evidence of a role for low job decision latitude. Thus, based on this review, there is evidence for an effect of work-related psychosocial factors, but the evidence for the role of specific factors has not been established yet.

Flexion and rotation of the trunk and lifting at work are risk factors for low back pain: results of a prospective cohort study.

STUDY DESIGN: A 3-year prospective cohort study among workers of 34 companies in the Netherlands. OBJECTIVES: To investigate the relation between flexion and rotation of the trunk and lifting at work and the occurrence of low back pain. SUMMARY OF BACKGROUND DATA: Previous studies on work-related physical risk factors for low back pain either lacked quantification of the physical load or did not take confounding by individual and psychosocial factors into account. METHODS: The study population consisted of 861 workers with no low back pain at baseline and complete data on the occurrence of low back pain during the 3-year follow-up period. Physical load at work was assessed by means of analyses of video-recordings. Information on other risk factors and the occurrence of low back pain was obtained by means of self-administered questionnaires. RESULTS: An increased risk of low back pain was observed for workers who worked with the trunk in a minimum of 60 degrees of flexion for more than 5% of the working time (RR 1.5, 95% CI 1.0-2.1), for workers who worked with the trunk in a minimum of 30 degrees of rotation for more than 10% of the working time (RR 1.3, 95% CI 0.9-1. 9), and for workers who lifted a load of at least 25 kg more than 15 times per working day (RR 1.6, 95% CI 1.1-2.3). CONCLUSIONS: Flexion and rotation of the trunk and lifting at work are moderate risk factors for low back pain, especially at greater levels of exposure.

High quantitative job demands and low coworker support as risk factors for neck pain: results of a prospective cohort study.

STUDY DESIGN: A 3-year prospective cohort study among 1334 workers was conducted. OBJECTIVE: To determine whether the work-related psychosocial factors of quantitative job demands, conflicting job demands, skill discretion, decision authority, supervisor support, coworker support, and job security are risk factors for neck pain. SUMMARY OF BACKGROUND DATA: Among the various risk factors for neck pain, work-related psychosocial factors play a major role. Previous studies on risk factors for neck pain often had a cross-sectional design, and did not take both physical and psychosocial factors into account. METHODS: At baseline, data on work-related psychosocial factors were collected by means of a questionnaire. During the 3-year follow-up period, data on the occurrence of neck pain were collected by means of postal questionnaires. Individuals without neck pain at baseline were selected for the analyses. Cox regression analysis was applied to examine the relation between the work-related psychosocial factors and the cumulative incidence of neck pain. Adjustments were made for various physical factors and individual characteristics. RESULTS: The analysis included 977 patients. Altogether, 141 workers (14.4%) reported that they had experienced neck pain at least once during the 3-year follow-up period. The relation of neck pain to high quantitative job demands (relative risk [RR], 2.14; 95% confidence interval [CI], 1.28-3.58) and low coworker support (RR, 2.43; 95% CI, 1.11-5.29) was statistically significant. An increased risk was found for low decision authority in relation to neck pain (RR, 1.60; 95% CI, 0.74-3.45), but this relation was not statistically significant. CONCLUSIONS: High quantitative job demands and low coworker support are independent risk factors for neck pain. There are indications that another risk factor for neck pain is low decision authority.

Psychosocial stressors at work and musculoskeletal problems.

OBJECTIVES: This paper examines the relationship between work stressors and the following health indicators: psychosomatic complaints, health behavior, and musculoskeletal problems. METHODS: Secondary analyses were performed on data from the National Work and Living Condition Survey, which provides a representative sample of the working population in The Netherlands. The survey was made in 1977, 1983, and 1986 by The Netherlands Central Bureau of Statistics. By means of factor analysis the following three risk dimensions were identified in the survey: work pace, intellectual discretion, and physical stressors. RESULTS: High work pace, low intellectual discretion, and physical stressors were associated with increased health complaints (both psychosomatic and musculoskeletal) and musculoskeletal disorders after adjustment for gender, age, education, and sports participation. Low intellectual discretion, but not high work pace, was associated with poor general health and health behavior indicative of poor health. Physical stressors were associated with general health as well, but not with health behavior, except for reported absenteeism. CONCLUSIONS: Psychosocial stressors are not only associated with psychosomatic complaints and health indicators, but also with musculoskeletal problems, both acute and chronic. Especially the relation between intellectual discretion and musculoskeletal problems can be partly attributed to physical load. Even after adjustment for physical stressors and moderating personal characteristics, the relationships between the psychosocial stressors and musculoskeletal problems remained significant and comparable in strength to the relationship between psychosocial stressors and several other health outcomes, such as psychosomatic complaints.

Psychosocial factors at work and musculoskeletal disease.

The objective of this review is to establish whether the epidemiologic literature presents evidence of an association between psychosocial work factors and musculoskeletal disease. In a hypothetical model it is suggested that individual characteristics and stress symptoms can modify this relationship. The reviewed studies do not present conclusive evidence due to high correlations between psychosocial factors and physical load and to difficulties in measuring dependent and independent variables. Nevertheless, it is concluded that monotonous work, high perceived work load, and time pressure are related to musculoskeletal symptoms. The data also suggest that low control on the job and lack of social support by colleagues are positively associated with musculoskeletal disease. Perceived stress may be an intermediary in this process. In addition, stress symptoms are often associated with musculoskeletal disease, and some studies indicate that stress symptoms contribute to the development of this disease.

Physical risk factors for neck pain.

To identify physical risk factors for neck pain, a systematic review of the literature was carried out. Based on methodological quality and study design, 4 levels of evidence were defined to establish the strength of evidence for the relationship between risk factors and neck pain. Altogether, 22 cross-sectional studies, 2 prospective cohort studies, and 1 case-referent study were eligible for determining the level of evidence. The results showed some evidence for a positive relationship between neck pain and the duration of sitting and twisting or bending of the trunk. A sensitivity analysis was carried out excluding 3 items of the quality list, the importance of which seemed doubtful. On the basis of this sensitivity analysis, it was concluded that there is some evidence for a positive relationship between neck pain and the following work-related risk factors: neck flexion, arm force, arm posture, duration of sitting, twisting or bending of the trunk, hand-arm vibration, and workplace design.

Physical load during work and leisure time as risk factors for back pain.

This systematic review assessed aspects of physical load during work and leisure time as risk factors for back pain. Several reviews on this topic are available, but this one is based on a strict systematic approach to identify and summarize the evidence, comparable with that applied in the clinical literature on the efficacy of intervention for back pain. A computerized bibliographical search was made of several data bases for studies with a cohort or case-referent design. Cross-sectional studies were excluded. A rating system was used to assess the strength of the evidence, based on the methodological quality of 28 cohort and 3 case-referent studies and the consistency of the findings. Strong evidence exists for manual materials handling, bending and twisting, and whole-body vibration as risk factors for back pain. The evidence was moderate for patient handling and heavy physical work, and no evidence was found for standing or walking, sitting, sports, and total leisure-time physical activity.

Psychosocial work characteristics and psychological strain in relation to low-back pain.

OBJECTIVES: This study investigated the relationship between psychosocial work characteristics and low-back pain and the potential intermediate role of psychological strain variables in this relationship. METHODS: The research was part of a prospective cohort study of risk factors for musculoskeletal symptoms. The study population consisted of 861 workers from 34 companies in The Netherlands who had no low-back pain at baseline and for whom data on the occurrence of low-back pain were obtained with annual questionnaires during a 3-year follow-up period. Information on psychosocial work characteristics and psychological strain variables was collected using a questionnaire at baseline. Cases of low-back pain were defined as workers who reported, in at least one of the annual follow-up questionnaires, that they had had regular or prolonged low-back pain in the previous 12 months. RESULTS: After adjustment for individual factors and quantified physical load at work, nonsignificant relative risks ranging from 1.3 to 1.6 were observed for high quantitative job demands, high conflicting demands, low supervisory support, and low co-worker support. Decision authority and skill discretion showed no relationship with low-back pain. In general, the estimated relative risks for the psychosocial work characteristics were scarcely influenced by additional adjustment for job satisfaction, emotional exhaustion, and sleeping difficulties. CONCLUSIONS: It can be concluded that low social support, from either supervisors or co-workers, appears to be a risk factor for low-back pain. Some indications of a relationship between high quantitative job demands and high conflicting demands and low-back pain were also found. Little evidence was found for an intermediate role for the psychological strain variables under study.