Bladder tumours in rubber workers: a factory study 1946-1995

Area of Science:

• Occupational Health
• Epidemiology
• Toxicology

Background:

• Workers in the British rubber industry were exposed to beta-naphthylamine, a human bladder carcinogen, as a contaminant in antioxidants before December 1949.
• A cohort of 6450 men from a tyre factory, exposed during or shortly after this period, was studied.

Purpose of the Study:

• To investigate the association between occupational exposure to beta-naphthylamine and bladder cancer risk in rubber industry workers.
• To assess the impact of removing the carcinogen on bladder cancer incidence.

Main Methods:

• A cohort study followed 2090 workers exposed between 1945-1949 and 3038 workers first employed after January 1950.
• Bladder cancer morbidity and mortality data were collected and compared to national rates.
• Work location data was used to interpret findings.

Main Results:

• The exposed group (pre-1950) had 58 registered bladder tumors, significantly higher than the expected 33.9 (SRRN=171).
• The group first employed after 1950 showed 39 tumors, close to the expected 38.3 (SRRN=102).
• Mortality data underestimated the risk; morbidity data revealed the elevated risk.

Conclusions:

• A statistically significant increased risk of bladder cancer was observed in workers exposed to beta-naphthylamine.
• This risk diminished after the carcinogen's removal in October 1949.
• Morbidity data is crucial for accurate assessment of occupational bladder cancer risk.