8208589 Monitoring new European chemical legislation on diisocyanates with epidemiological research: cohort and cluster-randomized trial

<h3>Objective</h3> Diisocyanates (DI) are crucial in producing polyurethane-based materials but can cause respiratory diseases like work-related DI asthma, affecting a four-digit range in the EU annually. In 2016, Germany proposed a new approach within the EU-wide regulation on chemicals (REACH), including mandatory training for employees on the safe handling of DI. The EU implemented this regulation in 2023 to enhance worker health and safety. To scientifically monitor and evaluate this new regulation an epidemiological study was planned. <h3>Material and Methods</h3> At first, a feasibility study was launched in 2018 as part of a large cooperative project involving various organisations. The aim was to recruit enough companies with approximately 1,500 DI-exposed employees (+ 200 non-exposed controls) but also to design the main study. Participating organizations, including accident insurance institutions and manufacturer associations, promoted involvement among companies. Interested companies were visited and further informed by conference calls, whereas the employees were informed through the company’s occupational health practitioner. <h3>Results</h3> Within the feasibility study 35 companies with &gt;1,300 DI-exposed employees agreed to participate. A 5-year prospective cohort study will assess exposure to DI and related health effects while an embedded cluster-randomized trial with wait-listed control groups will test the effectiveness of the training measures in terms of exposure reduction. In 2022, 29 companies remained, of which 26 were randomised for the intervention. The field phase began in 2023 with 28 company sites visited since then, including 15 in the intervention part. <h3>Conclusion</h3> The preparatory phase, supported by institutional collaboration, successfully established a nationwide sample of isocyanate-using companies for a 5-year cohort study. The combination of interventional and observational study designs can answer research questions and exemplify for an evidence-based regulation in European chemical safety.