Exposure to hexahydrophthalic and methylhexahydrophthalic anhydrides - dose-response for sensitization and airway effects

Objectives This study clarified the exposure-response relationships for the organic acid anhydrides (OAA) hexahydrophthalic (HHPA) and methylhexahydro phthalic (MHHPA) anhydrides and the development of specific immunoglobulin (IG) E and G antibodies and work-related symptoms. Methods in an epoxy resin-using factory, air levels of OAA were determined by gas chromatography-mass spectrometry. Occupational, smoking, and medical histories (questionnaire) were obtained for 154 exposed workers and 57 ref erents. Work-related symptoms of the eyes and airways were recorded, and OA A metabolites were analyzed in urine. A skin-prick test with common allerge ns and conjugates of OAA were performed. Specific IgE (radioallergosorbent test) and IgG (enzyme-linked immumosorbent assay) antibodies were determine d in serum, and spirometry was performed. Results Air levels of the OAA were low (HEPA < 1 to 94, MHHPA < 3 to 77 mug /m(3)) and associated with the concentrations of the OAA metabolites in uri ne. Furthermore, for the exposed workers, there were high prevalences of se nsitization (IgE 22%, IgG 21%), which correlated with the exposure. Neither atopy nor smoking increased this risk significantly. Furthermore, work-rel ated symptoms were more prevalent among the exposed workers than among the referents eyes 23% versus 14%, nose 28% versus 16%, nose bleeding 8% versus 0%, lower airways 10% versus 4%), and they were related to the exposure [a djusted prevalence odds ratios (POR) in the highest group 7.7, 3.6 and 17, respectively) and the IgE levels (POR 4.9, 3.1 and 5.6, respectively). Conclusions In spite of the very low OAA levels in the air and metabolites in the urine, there were high and exposure-related risks of specific IgE an d IgG sensitization and of work-related symptoms for the eyes, nose (especi ally bleeding), and lower airways.