Table 4 Uncertainties and limitations of the methodology and their potential impact on the estimate of the burden of disease due to occupation
Source of uncertaintyPotential impact on burden estimate
Exclusion of IARC Group 2B and unknown carcinogens
Inappropriate choice of source study for risk estimate↑↓
Imprecision in source risk estimate↑↓
Source risk estimate from study of highly exposed workers applied to lower exposed target population
Risk estimate biased down by healthy worker effect, exposure misclassification in both study and reference population
Use of RR  =  1 for very low/background/environmental levels of exposure where no value available from literature
Inaccurate risk-exposure period↑↓
Unknown proportion exposed at different levels of exposure↑↓
Effect of unmeasured confounders↑↓
Use of Levin’s formula when RR adjusted for confounders
  • IARC, International Agency for Research on Cancer; RR, relative risk.