Occupational diseases (MCP) are, in theory, all diseases that may be work-related but do not fall under the categories of compensable occupational diseases (MPI) listed in the general and agricultural Social Security schemes. Reporting MCPs is, in theory, a legal obligation for all medical doctors: " With a view to both the prevention of occupational diseases and a better understanding of occupational pathology, as well as the expansion or revision of the schedules, it is mandatory for any medical doctor who may be aware of their existence—particularly occupational physicians—to report any symptom or disease that, in their opinion, is of an occupational nature" (Article L.461-6 of the Social Security Code). In practice, however, very few physicians report MCPs, and furthermore, these reports are rarely or not at all utilized, particularly due to a lack of data on the population from which they originate. One of the objectives of the medical-social component of the musculoskeletal disorder (MSD) surveillance network established in 2002 in the Pays de la Loire region is to explore the use of MCP reports for epidemiological surveillance in the workplace, particularly by increasing the reporting rate and enabling an estimation of the prevalence rates of these diseases.