The World Health Organization considers the workplace as one of the best contexts for the prevention and control of non-communicable diseases⁽¹⁾. Implementing combined and de-medicalised interventions in Occupational Health Services (OHS) in a sustainable way over time can facilitate access to early detection, and management of musculoskeletal pain at work and improve workers' health. However, developing and implementing such interventions is challenging. Therefore, it is necessary to share previous interventions that describe both implementation and evaluation, in order to be used as practical examples that can inspire different OHS to implement sustainable interventions.

In recent years, workplace interventions have been implemented to prevent and manage musculoskeletal pain, and promote early return to work after sick leave. Multi-component interventions, that combine specific actions to target various risk factors, have been shown to be more effective than those based on only one specific component^(2-8). Furthermore, the systematic review by Cullen et al. (2018) recommended developing multifaceted interventions that include actions such as health care delivery, service coordination and workplace adaptation to improve musculoskeletal pain and reduce time to return to work⁽²⁾. Therefore, the use of multifaceted interventions is recommended for two main reasons: the requirement for a biopsychosocial approach due to the multiple factors related to musculoskeletal pain, and the greater possibility of incorporating actions that are tailored to the individual needs of workers.

In this sense, the study "Evaluation of a multifactorial workplace intervention for the prevention of musculoskeletal pain in workers" (INTEVAL) was designed as an evidence-based intervention, which aimed to promote a shift in orientation and a new paradigm for the prevention and management of musculoskeletal pain, with a comprehensive evaluation of effectiveness, implementation process and efficacy. It was hypothesised that a multifaceted intervention covering both primary, secondary and tertiary prevention in workers compared to usual care would reduce the prevalence of musculoskeletal pain at 12 months⁽⁹⁾. The primary prevention components focused on addressing workplace risk factors to prevent musculoskeletal pain and associated temporary disability through the validated participatory ergonomics method ERGOPAR⁽¹⁰⁾, as well as promoting a healthy lifestyle through a programme that included different actions such as Nordic walking training, Mindfulness courses and Mediterranean diet workshops. Secondary and tertiary prevention were formed by a case management service to identify musculoskeletal pain early (i.e. when the patient is already in pain but still working) to improve prognosis and reduce the likelihood of having sick leave and also to enable a safe and sustainable return to work.

Although the intervention was designed to be adaptable to different work contexts, it was finally carried out in two tertiary hospitals in Catalonia, where nursing staff (nurses and aides) were selected as potential participants. Results showed that those who completed the baseline questionnaire (n=257) were exposed to musculoskeletal risk factors (80% of participants reported having pain in neck, shoulders or upper-back pain) and that the intervention reduced the risk of musculoskeletal pain in the neck, shoulders and upper-back by 63% at 12 months, compared to the control group⁽¹¹⁾.

In relation to the process evaluation, the results showed that the implementation of this complex intervention was predominantly carried out as intended. Furthermore, it provided important information on process indicators that could be useful for future implementations of this or similar interventions. It was concluded that there was a need for flexibility in terms of timing and scheduling, both in the recruitment phase and during the intervention⁽¹²⁾. In this regard, holding information meetings in each of the participating hospital units and on different shifts would have facilitated workers’ participation and could probably have increased recruitment. Flexibility in implementing the intervention through the different actions and activities was also considered necessary to ensure that workers from all shifts (i.e. morning, afternoon and night) had the opportunity to participate.

The economic evaluation showed that, from a societal perspective, an additional €8.39 (€5.38 from a health system perspective) was needed to achieve an additional 1 percentage point reduction in musculoskeletal pain (unpublished data). Therefore, although the efficacy of this intervention could not be fully established, these findings are encouraging for the prevention and treatment of musculoskeletal pain in the workplace.

Based on our experience, we would like to raise several recommendations. A key point of the INTEVAL project is that it was characterised by its flexibility and capacity to adapt to the needs of different companies. Moreover, it was designed to optimise and make the most of the existing prevention resources in the OHS and their institutions. The whole project, in fact, was based on the sum of capacities of the different participating levels: managers, workers and their representatives, researchers and occupational health specialists, taking advantage of the strengths and potential of each of these agents, and was carried out in close collaboration between the participating companies. This was both an opportunity and a challenge. An opportunity, since direct interaction with company agents in the development of the research strengthens the relationships between the research centres, the researchers themselves and the company, facilitating the knowledge transfer to their direct users and recipients. It was also a challenge, common in occupational health intervention studies, to achieve a necessary balance between the methodological requirements of the research, time, expectations and needs of the productive activity in the companies.

We would like to emphasise that the participation and empowerment of workers in decision-making was crucial for the successful implementation of the intervention. In addition, we recommend holding the activities at the workplace and during working hours, as other times or having to travel may be a barrier for workers to attend. Also, offering activities in various time slots could facilitate workers' participation. It is also important to consider that the involvement of intermediaries (i.e. if any activities are delivered through an external company) may slow down the implementation of the intervention, so having an agent in direct contact with workers and services may promote faster implementation.

Finally, we believe that interventions should move towards a comprehensive approach that includes primary, secondary and tertiary prevention; and that OHS could be an excellent place to promote this. Therefore, we would like to encourage OHS and researchers to develop, implement, and evaluate, multifaceted workplace interventions to reduce musculoskeletal pain.