Documents Viikari-Juntura, Eira 20 results

"Objective We studied predictors of sickness absences (SA) due to musculoskeletal pain over two years among 386 municipal female kitchen workers.Methods Pain and SA periods (no/yes) due to pain in seven sites during the past three months were assessed at 3-month intervals over two years by questionnaire. Age, musculoskeletal pain, multisite pain (pain in ?3 sites), musculoskeletal and other somatic diseases, depressive symptoms, physical and psychosocial workload, body mass index, smoking, and leisure-time physical activity (LTPA) at baseline were considered as predictors. Trajectory analysis and multinomial logistic regression were used. Results Three trajectories of SA emerged, labelled as “none” (41% of the subjects), “intermediate” (48%), and “high” (11%). With the “none” trajectory (no SA) as reference, pain in all musculoskeletal sites excepting the low back predicted belonging to the “intermediate” [odds ratio (OR) 1.82–2.48] or “high” (OR 2.56–3.74) trajectory adjusted for age; multisite pain predicted membership of the “intermediate” [OR 2.15, 95% confidence interval (95% CI) 1.38–3.34] or “high” (OR 4.66, 95% CI 2.10–10.3) trajectories. In a mutually adjusted final model, smoking (OR 2.12, 95% CI 1.22–3.69), multisite pain (OR 1.87, 95% CI 1.15–3.02), and overweight/obesity (OR 1.71, 95% CI 1.08–2.72) predicted belonging to the “intermediate” trajectory, while depressive symptoms (OR 3.57, 95% CI 1.57–8.10), musculoskeletal diseases (OR 3.18, 95% CI 1.37–7.37), and multisite pain (OR 2.72, 95% CI 1.15–6.40) were associated with the “high” trajectory.Conclusion Along with the number of pain sites and musculoskeletal diseases, attention to depressive symptoms, smoking, and overweight/obesity is needed to tackle SA related to musculoskeletal pain."

The incidence of upper-limb, neck-shoulder, and low-back disorders and their induction times were investigated among new workers in tasks with various physical workloads.New trailer assemblers (N=364) were followed prospectively for 45 months - the workers' health status via medical records and exposure to physical workload factors via job titles, walk-throughs, task descriptions, and some direct measurements. The incidence rate of first sick leave due to such disorders was calculated for different workload groups. The proportion of workers surviving without musculoskeletal disorders was estimated by the Kaplan-Maier product-limit estimator, and the effect of the exposure on the risk of incident disorders was estimated with the Cox proportional hazards model.The highest annual incidences were observed for strenuous tasks, the incidence rate for men being 16.8 per 100 person-years [95% confidence interval (95% CI) 8.0-30.9] for upper-limb disorders in strenuous tasks and 6.1 (95% CI 2.0-14.1) in nonstrenuous tasks and that for women being 32.0 (95% CI 11.7-69.7) and 9.9 (95% CI 0.2-54.9), respectively. The men's risk of contracting an upper-limb or neck-shoulder disorder in strenuous tasks was about threefold [hazard ratio (HR) 3.2 (95% CI 1.1-9.4) for upper-limb disorders and 2.7 (95% CI 0.9-8.1) for neck-shoulder disorders] that of nonstrenuous tasks, whereas workload seemed not to affect low-back disorders. The workers first sought medical advice for their disorders typically some months after employment began.Newly employed workers in hand-intensive tasks have a high risk of upper-limb and neck-shoulder disorders. An etiologic role for activities involving high force demands in upper-limb and neck-shoulder disorders is possible.

The systematic review by Konijnenberg et al (1) in this issue of the Scandinavian Journal of Work Environment & Health deals with conservative treatment methods for the great problem of neck and upper-limb disorders in working populations. Fifteen randomized controlled trials (RCT) or controlled clinical trials (CCT) fulfilled the inclusion criteria of the review. Five of these scored 6/12 or higher according to their internal validity criteria and were considered high-quality studies. In the presence of a wide range of treatments, no treatment modality could be evaluated on the basis of a remarkable number of high-quality studies. There was, however, limited evidence in favor of physiotherapy, exercises, and ergonomic improvements. Repetitive strain injury (RSI) is a loose concept used in this review broadly to encompass a range of disorders from the neck and thoracic spinal area to the fingertip. In principle, outcomes in treatment or intervention studies should be based on symptoms or findings or both independently of the etiologic factors of the disease, and we should avoid concepts that include the assumed etiologic factor. To me, "neck and upper-limb disorders in working populations" would have seemed to be a more appropriate concept, especially since the work-relatedness of the conditions is difficult to assess; in fact it was not even addressed in some of the studies reviewed. Moreover, the requirement of work-relatedness resulted in the exclusion of some potentially high-quality studies (2) that did not have "work-relatedness" as an inclusion criterion, but still probably dealt with a largely similar group of disorders. For instance, in the study of Taimela et al (2), one inclusion criterion was the possession of a permanent job. But if we accept the concept of repetitive strain injury and assume that repetitive movements are one of the major causes of this strain, would not then modification of exposure (or engineering control) be a natural component in a treatment aimed to enhance recovery and prevent recurrence? Many of us would probably say yes, but a look at the tables in the review shows that only very few studies had workplace adjustment as a treatment or as one constituent in the treatment protocol. Another conspicuous feature of this review and also of some other related recent reviews (for an example, see reference 3) is that ergonomic intervention has usually been carried out in the office environment. While there is no doubt that office workers do have work-related musculoskeletal problems, such problems are even more frequent in the construction, transportation, and manufacturing industries and in some branches of the service sector, for example, hospital, kitchen, and cleaning work (4). Hopefully, the target workplaces for future workplace intervention studies will be determined by the size and seriousness of the problems and not only by the feasibility of carrying out an intervention study, such as stationary work in an office environment versus a changing work environment at a construction site, or the marketing of new input devices or computers. The magnitude or the duration of the treatment effects did not deserve much attention in this review, which is understandable since high-quality studies were few in number. However, a look at the high-quality studies shows that a modest reduction in pain was typical, and this effect was no longer present in the later phases of follow-up. Cost-effectiveness aspects were not considered in any of the studies included in this review. The relatively meager results in most studies do not suggest that the treatments were cost-effective in general. Many risk factors contribute to the occurrence of neck and upper-limb disorders among working populations (5, 6, 7). In a multifactorial condition, it is unlikely that a single measure would result in significant relief, something that is suggested by the meager results in several studies accepted for review. With regard to the etiology of most neck and upper-limb disorders, multidisciplinary approaches should have a higher potential. Unfortunately, multidisciplinary rehabilitation had been tried in only one controlled clinical trial, which received a very low score. The authors are correct in being worried about the use of multiple outcomes in intervention studies, the result being a high likelihood that a positive result is obtained by one of the outcomes by chance. Researchers should be more critical in the design of their studies. They should select only the most relevant outcome measures and restrict the outcomes only to them. Most studies relied solely on subjective outcome parameters, since few generally accepted objective methods exist. This is a major scientific problem, especially since blinding subjects for treatment is hardly possible. A major question of treatment policy in relation to neck and upper-limb disorders among working populations is whether the focus should be on treating the individual or his or her environment, especially in the control of workload. Trying to get an answer from workplace intervention studies, especially randomized controlled trials, involves an inherent potential of bias. As it is much easier to randomize individuals into different physical therapies, exercise or other treatment modalities, than it is to randomize workstations to be changed or not, there will always be more randomized controlled trials with treatments directed toward the individual. Therefore, there are greater chances of obtaining positive results from such treatments at the cost of engineering controls. Moreover, the current instability at workplaces, with high turnover rates and frequent reorganizations, makes it increasingly difficult to carry out workplace intervention studies successfully. It is easy to share the authors' worry about the absence of high-quality studies as evidence for the effect of most currently used treatment modalities. As the authors say, there is a higher possibility of bias, for example, an erroneous positive result of a treatment, in a low-quality study than in one of high-quality. This issue was systematically addressed in a review on acupuncture trials involving chronic neck and back pain (8), in which the authors were able to show that the most valid trials tended to have negative results. Konijnenberg and his collaborators' review shows convincingly that the scientific basis for current treatment practices with respect to neck and upper-limb disorders in working populations is limited and based largely on low-quality studies. More high-quality studies are definitely needed. Moreover, research priorities should not be restricted to groups of workers and treatment modalities that are easy to study. Instead, studies should be undertaken on treatment modalities that carry a potential to be efficacious. Worker groups with the highest risk of neck and upper-limb disorders should be the focus. Such studies are often laborious and should therefore be supported by sufficient funding. It is possible that new knowledge from such studies may change our understanding of the efficacy of some treatments and, therefore, create pressure to change current treatment practices. What should the practitioner do now while we are still waiting for the results of such studies? The Panel on Musculoskeletal Disorders established by the National Research Council and the Institute of Medicine concluded in their review that the epidemiologic evidence for upper-extremity disorders supports the important role of physical load factors (7). Based on this evidence, primary and secondary intervention at the workplace, including engineering and administrative controls, was recommended. As there are still few prospective studies on incident neck and upper-limb disorders, it is difficult, on the basis of epidemiologic studies, to estimate the relative potential of these measures in primary versus secondary prevention.

For years scientists have kept saying that elevated postures of the arm are a risk factor for shoulder disorders, but it is not known how much elevation and for how long is too much (1). Others have called for more precision in exposure assessment in epidemiologic studies, emphasizing the importance of the intensity, frequency, and duration of exposures (2). The article by Punnett and her co-workers (3) on shoulder disorders in this issue of the Scandinavian Journal of Work, Environment & Health is important for practitioners and scientists in occupational health and ergonomics, and also for others involved in the prevention of musculoskeletal disorders. This study found a dose-response relationship between the duration of severe shoulder flexion or abduction as a proportion of cycle time and shoulder disorders. The risk was clearly increased for severe shoulder flexion or abduction (>90 degrees) for less than 10% of the cycle time, and it increased when the proportional duration was 10% or more. The authors made considerable effort to assess also forces imposed on the shoulder joint and used a biomechanical model to incorporate posture and hand loads into a common metric of force. They failed, however, to show an elevated risk for force, probably because the worktasks used in this study did not involve the exertion of high forces. The repetition rate of arm movements was also observed. But it correlated strongly with shoulder elevation, and its effects could not therefore be distinguished. The strength of this study is its objective assessment of its outcome and exposure. Not all the cases had positive clinical findings, but the risk estimates were slightly higher for those with clinical findings, and the results therefore suggested an even stronger association between clinically manifest disease and postural load. The exposure assessment included the intensity, frequency, and duration of shoulder postures and resulted in a multitude of data that required careful data reduction and analysis. The history of epidemiologic studies on shoulder disorders is short, not really starting until some 20 years ago, when a group of studies on shipyard welders was published that showed a high prevalence of shoulder disorders (4). Overhead welding was considered the main work-related factor. Later, studies among bricklayers and rockblasters showed an association between acromioclavicular arthrosis and cumulative exposure to physical loads, such as the sum of lifted tonnes during worklife (5). In the same group of workers, shoulder tendinitis was associated with cumulative vibration dose (6). A recent study found the prevalence of shoulder impingement syndrome to be higher among current and former slaughterhouse workers than in a comparison group. Video recordings of a group of the slaughterhouse workers showed that they spent half of their worktime with arm elevation of ?30 degrees (7). There are no prospective studies on clinically defined shoulder disorders. The study by Punnett and her co-workers seems to be among the most rigorous available on the association between shoulder disorders and physical workload factors. The results will be useful in the primary and secondary prevention of shoulder disorders. For monotask jobs, the results can be considered a source of reference values for the proportional duration of overhead work. The proportional durations can also be translated into minutes or hours of shoulder flexion or abduction per day. As there are very few similar data with which to compare the results of Punnett and her co-workers' study, it is obvious that more studies are needed. At this point we can also question how much further epidemiologic studies will take us. We could probably learn more about, for example, hand loads or forces imposed on the shoulder joint with a worker population that is exposed to a wider range of forces. Other types of tasks could give us more information about the repetition rates of shoulder movements. Such studies as this one bring us to the contact surface between epidemiologic and experimental research; more information on shoulder postures, hand loads, arm movement frequencies, and their combinations can be obtained largely in the laboratory. But, as we all know, we are unlikely to have a clinically relevant health outcome in the laboratory. Reference values can then be subjected to further reasoning by collecting the best available epidemiologic and experimental data and looking for patterns of dose-response between exposures and outcomes and interactions between exposures.

"Work modification is considered as an essential element in enhancing return to work (RTW) among persons with musculoskeletal problems although systematic reviews have called for more studies and pointed out that the net gain in sickness absence days has been only modest and economic effects uncertain. Loisel and his co-workers showed for the first time that an occupational intervention – and especially an occupational intervention combined with a clinical intervention – was associated with a faster RTW compared with clinical intervention alone or usual care. The developed Sherbrooke model has been tested with a randomized controlled trial (RCT) in the Netherlands. Workers sick-listed for 2–6 weeks due to low-back pain (LBP) were first randomized into a workplace intervention or usual care, and those who had not returned to work by 8 weeks were further randomized to graded activity or usual care. ..."

This study evaluated the effect of an intensive ergonomic approach and education on workstation changes and musculoskeletal disorders among workers who used a video display unit (VDU).Both the intensive ergonomics approach and education in ergonomics help reduce discomfort in VDU work. In attempts to improve the physical ergonomics of VDU workstations, the best result will be achieved with cooperative planning in which both workers and practitioners are actively involved.

"This paper presents a conceptual model for the pathogenesis of work-related musculoskeletal disorders. The model contains sets of cascading exposure, dose, capacity, and response variables, such that response at one level can act as dose at the next. Response to one or more doses can diminish or increase the capacity for responding to successive doses. The model is used as a framework for discussing the development of work-related muscle, tendon, and nerve disorders. It is intended as a beginning, to be modified to explain new findings as they become available. In research, it can help to identify areas needing additional data for the development and expression of work-related musculoskeletal disorders. Researchers can use it to design laboratory and field studies. In practice, it demonstrates the relationship between common exposure factors and different responses. This information can be used to evaluate and design jobs for the prevention of work-related musculoskeletal disorders."

"BACKGROUND:

There is growing evidence that physical and psychosocial exposures at work increase the risk of musculoskeletal disorders. The aim of this study was to describe the distribution and co-occurrence of these risk factors in the working population.

METHODS:

We used data from the Health 2000 survey carried out in Finland in 2000-2001. The sample of our study consisted of 2,491 men and 2,613 women who had been actively working during the year preceding the survey. Logistic regression and exploratory factor analysis were used to analyze the co-occurrence of the work-related risk factors.

RESULTS:

Exposure to high physical work load and several co-occurring work load factors was more prevalent among men than women. In women, as opposed to men, the highest exposure to most physical work load factors was found in their later work life. Gender and age showed weak associations with psychosocial work load factors. Low socioeconomic position, in both genders, was related to an increased risk of being exposed to several co-occurring physical or psychosocial factors. Physical exposures most frequently co-occurred with high job demands and low job control in men. Among women, physical exposures were found to co-occur with high job demands, low job control and job insecurity.

CONCLUSIONS:

This study provides novel information on the occupational exposures in general working population. It appears that co-occurrence of physical and psychosocial exposures should be considered in research and prevention of musculoskeletal disorders. In addition, a broader set of occupational factors, e.g., work organization, are suggested to be included in future studies to cover all the relevant determinants."

"Back pain is very common among adults. There is evidence that individuals who physically move or lift objects (manual material handling) on a regular basis increase the strain on their backs and the risk of developing back pain. In many occupations, it is difficult to avoid this. Training on proper lifting techniques and the use of mechanical aides (assistive devices) are considered important techniques to prevent back pain.

We included nine randomised controlled trials (20,101 employees) and nine cohort studies (1280 employees) that examined the effects of training and the use of assistive devices on preventing low-back pain and reducing back-related disability. We found no studies that examined the effects of training or the use of assistive devices as part of a treatment plan for back pain.

We found moderate quality evidence that reports of back pain, back-related disability or absence from work were similar between groups who received training on proper lifting techniques and assistive devices compared to a control group that received either no training, minor advice only, professional education, exercise training or back belts. Reports of back pain were also similar between those who received intensive training and those who received shorter instruction. These findings were consistent when measured in the short-term or long-term and when examined in randomised trials or cohort studies.

These results are similar to other reviews that examined a range of possible prevention measures. Some of the other reviews found that workers who received training were satisfied and demonstrated increased knowledge on the subject, but this did not appear to consistently translate into behaviour change.

In conclusion, training workers in proper material handling techniques or providing them with assistive devices are not effective interventions by themselves in preventing back pain. Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate."

"BACKGROUND: Training and assistive devices are considered major interventions to prevent back pain among workers exposed to manual material handling (MMH). OBJECTIVES: To determine the effectiveness of MMH advice and training and the provision of assistive devices in preventing and treating back pain. SEARCH STRATEGY: We searched MEDLINE to November 2005, EMBASE to August 2005, and CENTRAL, the Back Group's Trials Register, CINAHL, Nioshtic, CISdoc, Science Citation Index, and PsychLIT to September 2005. SELECTION CRITERIA: We included randomized controlled trials (RCT) and cohort studies with a concurrent control group, aimed at changing human behaviour in MMH and measuring back pain, back pain-related disability or sickness absence. DATA COLLECTION AND ANALYSIS: Two authors independently extracted the data and assessed the methodological quality using the criteria recommended by the Back Review Group for RCTs and MINORS for the cohort studies. One author of an original study supplied additional data for the review. The results and conclusions are based on the primary analysis of RCTs. We conducted a secondary analysis with cohort studies. We compared and contrasted the conclusions from the primary and secondary analyses. MAIN RESULTS: We included six RCTs (17,720 employees) and five cohort studies (772 employees). All studies focused on prevention of back pain. Two RCTs and all cohort studies met the majority of the quality criteria and were labeled high quality. We summarized the strength of the evidence with a qualitative analysis since the lack of data precluded a statistical analysis. There is moderate evidence that MMH advice and training are no more effective at preventing back pain or back pain-related disability than no intervention (four studies) or minor advice (one study). There is limited evidence that MMH advice and training are no more effective than physical exercise or back belt use in preventing back pain (three studies), and that MMH advice plus assistive devices are not more effective than MMH advice alone (one study) or no intervention (one study) in preventing back pain or related disability. The results of the cohort studies were similar to the randomised studies. AUTHORS' CONCLUSIONS: There is limited to moderate evidence that MMH advice and training with or without assistive devices do not prevent back pain, back pain-related disability or reduce sick leave when compared to no intervention or alternative interventions. There is no evidence available for the effectiveness of MMH advice and training or MMH assistive devices for treating back pain."