Estimating the Incidence of Leukemia Attributable to Occupational Exposure in Iran


Objective: The aim this study was to estimate the fraction of leukemia incidence in Iran attributable tooccupational exposure to benzene, ionizing radiation, and ethylene oxide.
Methods: Nationwide exposure toeach of these leukemogens was estimated using workforce data available at the ILO (International LaborOrganization) website. The prevalence of exposure to leukemogens in each industry was estimated using exposuredata from the CAREX (CARcinogen EXposure) database. The magnitude of the relative risk of leukemia foreach leukemogen was from published literature. Using the Levin’s population attributable risk (incidence),fractions of leukemia incidences attributed to workplace leukemogens were then estimated.
Results: The totalworkforce in Iran according to the 1995 census included 12,488,020 men and 677,469 women. Agriculture wasthe largest sector with 24.5% of the males and 0.27% of the females, and the electricals-related sector was thesmallest with 1.16% of the males and 0.66% of the females. After applying the CAREX exposure estimates toeach sector, the proportion exposed to leukemogens was 0.016% for male workers and 0.02% for female workers.Estimating a relative risk of 3.6 (95% CI of 3.2–4.2) for high exposure and 1.9 (95% CI 1.7–2.1) for low exposureand employing the Levin’s formula, the fraction of leukemia attributed to leukemogens in the workplaces amongfemales was 3.6% (95% CI of 3.1-4.5) and among males was 7.6% (95% CI of 6.4-9.2). These fractionscorresponded to estimated incidences of 0.60 (95% CI of 0.50-0.70) and 0.22 (95% CI of 0.16-0.23) cases ofleukemia per 100,000 populations for males and females, respectively.
Conclusion: The incidence of leukemiadue to occupational exposure is very low in Iran, although males are at greater risk than females.