1. The workers with work related symptoms had higher concentrations of P-MDX than those without, or those with symptoms without clear association with work (table 4). There were no significant associations between work related symptoms and either sex, age, or smoking. Thus, there was no confounding by these factors
2. Workers with IgG antibodies to MIDI had significantly higher concentrations of P-MDX and U-MDX than workers without (table 4). Also, there were significant associations between IgG antibodies to MDI and P-MDX (fig 2) and U-MDX (r= 0-21; P = 0006). The three subjects with IgE antibodies to MDI had higher P-MDX and U-MDX than the others, but the group was too small to be sure of a significant association