Impact of chemical exposure on cancer mortality in a French cohort of uranium processing workers.

BACKGROUND: Nuclear workers may be exposed to a variety of chemical hazards, in addition to radiation. We examined the effect of chemical exposures on cancer mortality among French uranium processing workers at the AREVA NC Pierrelatte facility.

METHODS: A cohort of 2,897 uranium processing workers employed for at least 6 months was followed from 1968 through 2006. Exposure to uranium and potentially carcinogenic chemicals was assessed with a plant-specific job-exposure matrix. Mortality hazard ratios (HRs) for cancers of the lung, lymphohematopoietic system, kidney and bladder, brain and central nervous system (BCNS), and prostate were estimated for each specific chemical exposure, with Cox regression models stratified for sex and calendar period and adjusted for socioeconomic status. Additional adjustments enabled us to examine the effect of co-exposure to uranium and other chemicals.

RESULTS: Exposure to aromatic solvents was associated with increased risk of BCNS malignancies after adjustment for other chemicals (HR=6.53, 95% CI=1.14-37.41; n=6) and for other chemicals and uranium (HR=7.26, 95% CI=0.90-58.19) in the annual exposure status model. Selected groups of lymphohematopoietic cancers were found associated with solvent exposure. Inconclusive results were found regarding chromium (VI) exposure, since only 2 workers died from lung cancer among 109 exposed.

CONCLUSION: Based on our pilot study, it seemed important to take into account chemical exposures in the analyses of cancer mortality among French uranium processing workers.