Workers exposed to aromatic amines continued to experience an increased risk of bladder cancer even 30 years after exposure, according to the results of a follow-up study published in the Journal of the National Cancer Institute.
Aromatic amines are a group of well-known bladder carcinogens. Most countries have discontinued exposure to aromatic amines; however, research is ongoing to determine the long-term effects to workers who were exposed in the past.
One study examined the risk of bladder cancer among a cohort of 664 dyestuff workers in Italy who were heavily exposed to aromatic amines between 1922 and 1972. These workers were found to have a substantially increased risk of bladder cancer death.
The data from this study have now been updated by 14 years through 2003 (for 590 exposed workers) and now includes more than 30 years of follow-up since the last exposure to aromatic amines. Using national mortality rates and regional mortality rates, researchers computed the expected number of deaths from bladder cancers and other causes. There were 394 deaths in the group compared with the expected number of 262.7. Overall, there were 56 deaths from bladder cancer compared with 3.4 expected.
The risk of death from bladder cancer increased with a younger age at first exposure to aromatic amines and increasing duration of exposure. Although the risk of bladder cancer death steadily decreased with time since last exposure, the absolute risk remained constant. The researchers observed an increased risk of bladder cancer 30 years or more since last exposure to aromatic amines.