Polyurethane - occupational exposure, biomarkers and symptoms

Sammanfattning: Isocyanates may cause occupational asthma, rhinitis, and hypersensitivity pneumonitis. However, the mechanisms behind initiation of the disorders and the relations between exposure and effect are insufficiently elucidated. Means to biomonitor exposure and risk would be valuable. A case, exposed to heated polyurethane, displayed metabolites of 4,4'-dipheylmethane diisocyanate in blood and urine, and serum IgE and IgG antibodies against isocyanates, the latter with a half-life of years. Among 166 employees in a factory, there were cross-sectional associations between spraying of polyurethane glue and metabolites of isocyanates, specific IgG antibodies, work-related (nose and lower airways) symptoms, and a slightly reduced lung function. Heating of glue was related to metabolites of isocyanates and to the IgG antibodies. Workers using heat guns displayed a particularly high prevalence of airways symptoms. The metabolites and the IgG antibodies were associated with the airways symptoms. In a prospective approach over 2 years (totally 187 workers from the same factory), the metabolites reflected changes of exposure. The IgG antibodies predicted ¨new¨ work-related lower airways symptoms, a decrease of lung function, and sick-leave. No strong effect modifications by genetic polymorphism in GSTs or NAT2 on these associations were identified, but GSTT1, GSTP1 and NAT2 displayed some relations with symptoms and lung function. In workers (N=29) with or without work-related nose symptoms, heated glue was associated with isocyanate metabolites in urine and inflammation biomarkers in nasal lavage fluid, the latter in turn with the metabolites, isocyanate-specific IgG antibodies and symptoms.