There is a major initiative across the European Union to provide good practice for preventing the most common occupational health problem in Europe – work-related musculoskeletal disorders (WMSDs).
The consensus is that MSDs can be work related, and that ergonomics interventions can reduce risk. Good practice is centred on reducing physical and psychosocial risk factors in the workplace.
Many organisations have sought to implement ergonomic programmes and interventions aimed at primary prevention of WMSDs.
The most common approach for managing these disorders is applying a strategy of risk avoidance, risk reduction and evaluation of risk by competent, in-house, health and safety practitioners. This approach involves strategic management decisions, consultation with employees, and implementation by managers. Using consultants to advise on risk identification, implementation of solutions and evaluation has been an alternative approach.
After a risk assessment has been conducted, a number of risk factors are identified. It can be a difficult decision for the occupational health practitioner as how best to reduce exposure levels to these risk factors. What might happen is that the intervention focuses on reducing exposure to a single risk factor.
Focusing on a single workplace risk factor for any single specific disorder is likely to help prevent other disorders. For example, reducing the exposure to hand-arm vibration will not only reduce the likelihood of the development of Raynaud’s disease, but may also reduce the need for high force exertion at the hand and, thus, reduce the risk for hand/wrist tendinitis. Such benefits arise because of the common biological pathways involved in some of the disorders.
But, a reduction in the postural load on the wrist in a manipulative hand task by use of a hand tool may increase the force application at the hand and the wrist repetition – multiplying the risk of injury.
What typically happens is that an intervention will have implications on exposure levels to other potential risk factors, some of which are not considered as part of the assessment. This may increase the risk. That is why it is important to have a broader awareness of the risk factors for WMSDs so that these potential interactions can be explored by competent practitioners.
Systematic critical literature reviews regarding workplace risk factors for WMSDs have been consistent in their findings. For MSDs affecting the neck region, high postural load has been shown consistently to be a risk factor (duration of sitting, twisting and bending of the trunk). For the upper limbs, there is strong evidence that the biomechanical load from a combination of repetition, force and posture increases the risk multiplicatively for MSDs affecting the elbow. The combination effects have also been shown to increase the risk of specific hand disorders, such as carpal tunnel syndrome and tendinitis.
In a systematic critical review of display screen equipment (DSE) users, there were consistent study findings regarding increasing duration of DSE use and increasing risk of neck/shoulder and hand/wrist MSDs. The relationship was mainly dependent on the degree of repetitive finger motion and sustained muscle loading across the forearm and wrist. At least four hours of keyboard work a day appears to increase risk about two-fold compared to little or no keyboard work.
Psychosocial workplace risk factors refer to individual subjective perceptions by workers regarding aspects of the organisation of work. One example is perceived job demands and degree of support from managers or colleagues. Work organisation factors describe characteristics of the work system, for example, hours worked and management style can cause physical or psychological damage.
Work organisation and psychosocial workplace risk factors have been included in HSG60 (rev), the revised guidance on upper-limb disorders in the workplace by the Health & Safety Executive (HSE). Work organisation and psychosocial workplace risk factors have been grouped into the following categories: demands, control, support, relationships, role and change.
Psychosocial factors in the workplace are now widely accepted as contributing to the development of clinical signs and symptoms of WMSDs. With respect to computer technology specifically, there has been a growing amount of interest in not only the risk from exposure to the physical demands imposed by computer technology but also the psychological demands.
A new study by my colleagues and I at the Robens Centre for Health Ergonomics, University of Surrey, shows that high exposure to a combination of physical and psychosocial work risk factors produced the greatest risk of developing new episodes of self-reported musculoskeletal complaints, in a number of different body regions including the lower back and hands/wrists, compared to being exposed to either one or the other set of factors in a large mixed work population while adjusting for various stress reactions. This study is important as it shows that the joint exposure effects predict the onset of new musculoskeletal complaints.
The Stress and MSD Study, led by myself and funded by the HSE, was conducted to establish the role of stress and other psychological factors in the development and reporting of MSDs.
The link between stress and MSDs has been unclear in the scientific literature and most studies conducted before this study have not been able to show whether stress preceded the onset of MSDs.
The results showed that workers with high levels of perceived job stress were more likely to develop musculoskeletal complaints as a result of being highly exposed to a combination of psychosocial work risk factors.
Depression, psychosomatic complaints and perceived life stress also increased the risk of developing some musculoskeletal complaints but showed independent effects that were not linked to what workers were doing in the workplace.
The study also showed that workers with high exposure to both physical and psychosocial workplace risk factors were up to four times more likely to develop musculoskeletal complaints compared to workers not exposed to either. Workers highly exposed to only one set of factors were only about twice as likely to develop musculoskeletal complaints.
Implications for primary prevention
If recent research is correct, and work stress increases the risk of developing WMSDs, then what should OH practitioners be considering in the workplace.
Research which attempts to reduce risk to both work-related mental stress and WMSDs is still in its infancy.
The available literature has not addressed changes at organisational level to reduce risk to both work stress and WMSDs, but has primarily focused on specific job design changes, for example training and rest breaks. Other studies have focused on individual interventions, for example stress reduction and cognitive-behavioural techniques.
Benefits of worker participation
In 2001, GlaxosmithKline, a world leading research based pharmaceutical company with 21.4bn in sales in 2003 and more than 100,000 employees located worldwide, decided to design and assist in the implementation and evaluation of its first ergonomics improvement team.
The team, comprising managers, line workers, health and safety and OH staff and an ergonomist, was implemented at a manufacturing site to investigate the increasing numbers of lost time illnesses and injuries related to WMSDs, identify and assess associated risk factors and improve operational excellence.
Twelve months after the team was initiated at the site, 31 work system improvements were achieved. One intervention involved automation and eliminated human involvement, two interventions mechanised the work process, thus, eliminating the risk but human involvement remained. Three interventions used administrative controls whereby there were changes to job design or work policy. Twenty-five interventions reduced exposure to multiple risk factors for WMSDs.
In the first year of the programme, there was a 40% reduction in MSDs attended to on site by the company physician. A reduction in MSDs was not observed at similar-sized manufacturing sites that had not initiated an ergonomics improvement team.
Within three years, the ergonomics improvement team was considered a resounding success and resulted in the following additional improvements:
- 65 ergonomic improvements implemented and evaluated in total
- Ergonomic hazards reports increase by 160%
- Efficiency savings and reduce cycle times of up to 40%
- Best ever employee health and safety performance – 3.4 million hours work free of lost time illness and injury reached in 2003
- Improved manual handling assessment and training for the site
- Development of a standardised site ergonomic awareness training package
- The delivery of an ergonomic design course
- eating at work policy implemented
- Development of a display screen equipment assessment tool for non-user workstations.
The total cost of implementing the EIT was approximately 20,000 a year at the site. This figure was derived from costs based on meeting attendance times, design course attendance time and fees, materials for training and consultant fees. This was viewed as a significant cost benefit in relation to the costs of incident investigations, claims, compliance etc.
In response to these achievements, the site was awarded the Chief Executive Officers Environmental, Health and Safety Excellence Award in 2004. Furthermore, participatory ergonomics teams are in the process of being rolled out worldwide in the organisation.
Dealing with work-related stress and WMSDs continues to be a major difficulty for many OH practitioners. This is partly due to the multifactorial complexity of these disorders, management motivation and responsibility and level of competence among practitioners.
The successful example in GSK was due to management buy in, staff training and development, good team leadership and expert support. A number of one-week courses are available for practitioners wishing to learn and apply the principles and methods outlined in this article.
Further information about these courses can be obtained at http://www.eihms.surrey.ac.uk/robens/erg/.
Dr Jason Devereux is a certified European ergonomist and conducts consultancy, lecturing and research in human factors/organisational design and management at the Robens Centre for Health Ergonomics, University of Surrey. He is also an Honorary Research Fellow at the Business Psychology Unit, University College London. He is a registered member of the Ergonomics Society and has advised international organisations for 10 years