Participatory Ergonomics to prevent low back and neck pain among workers: design of a randomised controlled trial to evaluate the cost effectiveness
From: BMC Musculoskelet Disord. 2008 Oct 29;9(1):145 [Epub ahead of print]
In a randomised controlled trial (RCT), a total of 5,759 workers working at 36 departments of four companies is expected to participate in the study at baseline. The departments consisting of about 150 workers are pre-stratified and randomised. The control departments receive usual practice and the intervention departments receive participatory ergonomics . Within each intervention department a working group is formed including eight workers, a representative of the management, and an occupational health and safety coordinator. During a one day meeting, the working group follows the steps of participatory ergonomics in which the most important risk factors for low back pain and neck pain, and the most adequate ergonomic measures are identified on the basis of group consensus. The implementation of ergonomic measures at the department is performed by the working group. To improve the implementation process, so-called ‘ergocoaches’ are trained. The primary outcome measure is an episode of low back pain and neck pain. Secondary outcome measures are actual use of ergonomic measures, physical workload, psychosocial workload, intensity of pain, general health status, sick leave, and work productivity. The cost-effectiveness analysis is performed from the societal and company perspective. Outcome measures are assessed using questionnaires at baseline and after 6 and 12 months. Data on the primary outcome as well as on intensity of pain, sick leave, work productivity, and health care costs are collected every 3 months.
Prevention of low back pain and neck pain is beneficial for workers, employers, and society. If the intervention is proven cost effective, the intervention can have a major impact on low back pain and neck pain prevention and, thereby, on work disability prevention.
In the Netherlands the most common musculoskeletal disorders are low back pain and neck pain. Surveys among the Dutch working population showed that the one year prevalence of low back pain is 44.4% for men and 48.2% for women, and the prevalence of neck and shoulder pain is 28%. These symptoms may lead to medical consumption, sickness absenteeism or disability claims. In 2003, the estimated total health care costs of low back pain and neck pain were 761 million Euros. However, the annual costs of sick leave and loss of productivity due to low back pain and neck pain are estimated to be nine times the health care cost. The consequences and the costs of low back pain and neck pain are a burden to society and companies. Therefore, prevention of these symptoms is imperative.
Low back pain and neck pain are assumed to be of multifactorial origin. Several systematic reviews showed that the work-related risk factors for low back pain are heavy physical workload, whole body vibration, frequent bending and twisting, and heavy (manual) lifting. The main risk factor for neck pain is neck flexion. High prevalence rates of low back pain and neck pain and the presence of the risk factors in the working population indicate the need for prevention at the workplace. Workplace interventions, such as ergonomics (i.e. education on lifting techniques or postural instruction) have been frequently used. However, the evidence to recommend ergonomics for the reduction of the prevalence of low back pain is not sufficient and inconsistent. The evidence for preventing neck and upper extremity pain using ergonomics is also limited.
Another approach to prevent low back pain and neck pain may be participatory ergonomics. Supported by the management, participatory ergonomics empowers workers to design and change the worksite. A recent randomised controlled trial (RCT) indicated that participatory ergonomics was not effective to prevent musculoskeletal disorders among kitchen workers, whereas other studies indicated that the use of participatory ergonomics reduces musculoskeletal disorders among workers. However, most of the studies lacked a randomisation procedure, had no control group, assessed no other health outcomes (i.e. pain, quality of life, general health status, and costs), and studied homogeneous study populations only (blue or white collar). Moreover, a RCT conducted in Sherbrooke Canada, indicated that participatory ergonomics induced a 1.9 faster (i.e. 42 days) return to work (RTW) in patients suffering from sub acute low back pain. In the Netherlands, the Dutch participatory workplace intervention which was derived from the Sherbrooke model, resulted in 30 days earlier RTW and was costeffective when compared to usual practice.
Although participatory ergonomics was cost effective as a RTW intervention, no RCT has been conducted to evaluate the cost effectiveness of participatory ergonomics to prevent low back pain and neck pain among a large and heterogeneous population of workers (blue and white collar). Therefore, the main objective of this study, called the Stay@Work study, is to evaluate the effectiveness of participatory ergonomics compared to usual practice (no participatory ergonomics ) to prevent an episode of low back pain and neck pain among workers. Secondary objectives of this study are: 1) to compare the effectiveness of participatory ergonomics on the secondary outcome measures (i.e. actual use of ergonomic measures, physical workload, psychosocial workload, intensity of pain, general health status, sick leave and work productivity), and 2) to evaluate the cost-effectiveness and cost-utility of participatory ergonomics compared to usual practice.
The Stay@Work participatory ergonomics programme consists of the following six steps:
Step 1 The inventory of the workplace
As part of the preparation of the first working group meeting, an inventory of the workplace is conducted one month prior to the meeting consisting of the following sub steps:
1. Pictures of risk factors for low back pain and neck pain are made: each worker of the working group is equipped with a photo camera and is instructed to take at least 10 pictures of risk factors for low back pain and neck pain at the worksite.
2. Data of all workers of the department are obtained from the baseline questionnaire, and is used to obtain information on psychosocial risk factors for low back pain and neck pain present at the department
3. The ergonomist conducts a worksite observation at the department by using a checklist. The ergonomist observes activities relevant for low back pain and neck pain at work (e.g. type of work performed, lifting heavy loads (greater than 20 kilograms), frequent bending and rotating the lower back or neck). Furthermore, the ergonomist collects information about co-worker support, job organisation, job planning, instructions, skills, management styles, materials, and equipment.
Step 2 Analysis of risk factors
All members of the working group discuss and if necessary adjust risk factors for low back pain and neck pain summarised in the document, and a brainstorm session is performed to add possible other risk factors (individual, physical, mental, and organisational). Then, the frequency and the severity of the risk factors is evaluated by rating them according to a criteria list. The most frequent and severe risk factors are written down on a flap-over and are prioritised by all members of the working group. Subsequently, each member of the working group is asked to award his or her three most important risk factors by adding a sticker. On the basis of consensus, the three risk factors with the highest number of stickers are considered as the three most important risk factors.
Step 3 Finding of ergonomic measures
According to the nominal group technique the working group performs a brainstorm session about different types of ergonomic measures (individual, physical, mental, and organisational) to reduce the prioritised risk factor. The ergonomic measures are evaluated using a criteria list, considering the problem solving capability, costs, compatibility, complexity, and feasibility of the ergonomic measures. The manager decides whether the costs for the ergonomic measures are feasible. Furthermore, the ergonomic measures are judged whether they can be implemented within three months. Prioritisation of the ergonomic measures is performed similarly to step 2, resulting in the three most adequate ergonomic measures on the basis of consensus.
Step 4 Preparation of an implementation plan
The working group writes down the prioritised three most adequate ergonomic measures for the three most important risk factors for low back pain and neck pain in an implementation plan. The plan describes who is responsible for the implementation of the ergonomic measures; what type of activities need to be performed by who, how, and when a test phase is needed; and whether an appointment for a second meeting to evaluate the implementation plan is required (see step 6). After finishing the first meeting, all members of the working group receive a copy of the implementation plan.
Step 5 Implementation of ergonomic measures
In the weeks following the first meeting, the working group informs the co-workers about the ergonomic measures, motivates and instructs them on how to use the ergonomic measures. The OHS coordinator or the department manager is the central person for coordinating and facilitating the implementation process. Studies on participatory ergonomics report difficulties towards the implementation of ergonomic measures and the actual use of ergonomic measures. Therefore, to further improve the implementation process and the actual use of the ergonomic measures, two or three workers are trained to be a ‘Stay@Work ergocoach’. During a four hour training session, they are instructed about implementation strategies that can be used to inform, motivate, and instruct the co-workers about the selected ergonomic measures, and to learn how to deal with co-workers’ resistances against the ergonomic measures. At the end of the training session they receive the ‘Stay@Work ergocoach toolkit’, which includes formats of e-mails, posters, flyers, and digital presentations. The toolkit is used as an instrument to inform the co-workers at the department about the prioritised ergonomic measures.
Step 6 Evaluation and control of the ergonomic measures
In step 4, the working group decides whether the second meeting (one hour) is needed to evaluate the status of the implementation plan or the test phase. The ergonomist does not attend the second meeting, unless he or she is asked by the working group. The rationale is that the implementation should be the responsibility of the department and the working group.
Prevalence of low back pain and neck pain among Dutch workers is high and the financial consequences are a considerable burden to companies and society. In previous studies participatory ergonomics has been applied to prevent musculoskeletal disorders; however, most studies lacked a randomisation procedure or a control group. One of the main strengths of Stay@Work is that this study is one of the few RCT’s that evaluates participatory ergonomics aimed at the prevention of an episode of low back pain and neck pain. Moreover, this study evaluates the cost effectiveness of participatory ergonomics , and investigates other important health outcomes among a large heterogeneous population of workers. To date, research populations are consisting of construction workers, cleaners, glaziers, and manufacturing workers. In this study also health care workers, industrial and white collar workers are studied. A second strength is that the participants are blinded to the study design and the randomisation outcome, which minimises the chance that they undertake actions that may interfere with the experimental study design. A third strength is the use of an appropriate implementation strategy. Van der Molen et al. reported that the use of facilitation and educational strategies in the implementation of ergonomic measures lead to higher completed behavioural change phases and increased use of ergonomic measures. This is confirmed by Jensen and Friche, who used an implementation strategy that increased the use of ergonomic measures and successfully reduced severe knee problems among floor layers. To our knowledge, this is the first study that trained ergocoaches to improve the implementation of the ergonomic measures and stimulate the co-workers to use the ergonomic measures. A fourth strength is that Stay@Work evaluates the effectiveness of participatory ergonomics under routine department circumstances and does not optimise the study conditions (i.e. stopping with cointerventions). In other words, it is an effectiveness study and not an efficacy study.
Studying the effects of this intervention is important, as it aims to prevent a major occupational health problem. If proven cost effective, the companies will benefit from a bottom-up method to prevent low back pain and neck pain among their workers. Occupational Health Services or managers may incorporate this method in their usual prevention management.
