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Risk of bladder cancer in foundry workers: a meta-analysis
  1. R R W Gaertner1,
  2. G P Thériault2
  1. 1Medical and Occupational Disease Policy Branch, Workplace Safety and Insurance Board, Ontario, Canada
  2. 2Joint Departments of Epidemiology and Biostatistics, and Occupational Health, McGill University, Montreal, Canada
  1. Correspondence to:
    Mr R Gaertner, Medical and Occupational Disease Policy Branch, Workplace Safety and Insurance Board, 200 Front Street West, Toronto, ON M5V 3J1, Canada;


To clarify the inconsistent reports of bladder cancer risk in foundry workers, a meta-analytic review of epidemiological studies was undertaken. Summary risk estimates (SRE) were calculated from 40 systematically extracted results. Weakly increased risks were observed overall, with an SRE of 1.11. Twenty three selected study results with better exposure information yielded an SRE of 1.16. This weak increase in risk is consistent with estimates obtained from dose-response trends of PAH exposures in aluminium smelter workers. Summary estimates did not vary substantially with exposure quality, study design, control for smoking, or when limiting the meta-analysis to large study results. Exposure-response findings showed significantly increased risks of about 1.6 to 1.7 after 20 or more years of employment, but this was based on few studies. Occupation specific SREs showed a 40–50% increased risk among moulders, casters, and unskilled foundry labourers. There was limited evidence that bladder cancer risk correlated with lung cancer risk, which is a more established risk among foundry workers. The small increased risk observed is prone to bias and confounding. Further studies of dose-response trends would greatly aid in determining whether this observed association is causal.

  • bladder cancer
  • foundry
  • meta-analysis
  • PAH, polycyclic aromatic hydrocarbon
  • PMR, proportional mortality ratio
  • PR, pooled ratio
  • RR, relative risk
  • SIR, standardised incidence ratio
  • SMOR, standardised mortality odds ratio
  • SMR, standardised mortality ratio
  • SPMR, standardised proportional mortality ratio
  • SRE, summary risk estimate

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