Summary

Musculoskeletal disorders (MSDs) of the back and upper limbs are a major problem, with human, social and economic impacts. In recent years, the scientific community has proposed several methods for evaluating risk factor exposure (MERFE) for MSDs to support preventive efforts. However, relatively little information exists about the practical use of these different methods in workplaces. These methods are numerous, which makes it more complicated for the practitioner to choose a method appropriate for the intervention context. Also, the economic evaluation of an OHS intervention is an aspect that is considered strategic by interventionists for encouraging companies to prevent OHS problems, including MSDs. However, existing methods are used very little or not at all in companies for such an evaluation.

This study was carried out over a period of more than six years in the manufacturing sector and in the public forest nursery sector. It had three main objectives: 1) to follow up on the interventions carried out in workplaces; 2) to use and compare different methods for evaluating MSD risk factors; and 3) to evaluate different economic aspects associated with MSDs and the interventions. The work on the first objective produced two interesting results, namely that mapping of the production processes combined with an evaluation of the risk factors (e.g., MSDs) appears to be a promising approach for integrating OHS and productivity during projects to bring about change. Also, throughout the study, from our observations, we were able to document our research team’s contribution as a factor for evolution in the reflection of key players in the forest nursery sector.

The work on the second objective, comparing 21 indexes of 11 MERFE, showed that the different MSD MERFEs published in the recent literature produce conflicting results. Identification of priority situations for intervention depends on the choice of method that one expects to use. This work identified several observations of practical significance for the use of different MERFEs in workplaces.

The work involved in the third objective led to the development of an innovative model for calculating indirect costs, and then to its testing in different companies. This work sheds new light on the calculation of these costs and their link to direct costs. However, this work did not show a relationship between the costs and the level of risk of a work situation, as evaluated by two MSD MERFEs. This study therefore does not allow, at the time the work situation is analyzed, the use of the result of a MERFE as an economic indicator promoting an investment in prevention.

This study is the first to compare this many MSD MERFEs using such a large sample of work situations, originating from companies of different sizes, from such varied manufacturing sectors, and involving such a large number of workers. Due to the size of this sample and the diversity of the activity sectors, the study is a general one since it covers a wide range of work situations and industrial contexts. This study is also the first, to our knowledge, to go this far in the analysis of costs in relation to the evaluation of workplace MSD risk factors.