Elevated bladder cancer risk due to colorants--a statewide case-control study in North Rhine-Westphalia, Germany.

Occupational exposure to aromatic amines is a known bladder cancer risk factor, whereas the impact of exposure to azo dyes, which may release aromatic amines in humans, is at present controversial. Therefore, the impact of occupational exposures to colorants was investigated in 156 bladder cancer cases and 336 controls in the state of North Rhine-Westphalia. All bladder cancer cases and controls (diagnosed with prostate cancer) requested after-care treatment.