highly significantp < 0.001
A highly significant Co by W interaction was also observed ( p < 0.001).
A highly significant Co by W interaction was also observed ( p < 0.001).
In groups B and C, postexposure MDA-EBC levels were higher than control values ( p < 0.01 and p < 0.05, respectively), whereas the difference did not reach statistical significance for less-exposed workers in group A ( p = 0.1).