Objectives Uranium miners in Příbram, Czech Republic were exposed to low and moderate levels of radon gas and other hazards. It is unknown whether these hazards increase the risk of mortality or cancer incidence when compared with the general Czech population.
Methods A cohort of 16 434 male underground miners employed underground for at least 1 year between 1946 and 1976, and alive and residing in the Czech Republic in 1977, were followed for mortality and cancer incidence through 1992. We compared observed deaths and cancer incidence to expectation based on Czech rates. Standardised mortality ratios (SMRs), standardised incidence ratios (SIRs) and causal mortality ratios were calculated.
Results Underground workers in the Příbram mines had higher rates of death than expected due to all causes (SMR=1.23, 95% CI 1.20 to 1.27), all cancers (SMR=1.52, 95% CI 1.44 to 1.60), lung cancer (SMR=2.12, 95% CI 1.96 to 2.28) and extrathoracic cancer (SMR=1.41, 95% CI 1.15 to 1.77). Similar excess was observed in cancer incidence analyses, with the addition of stomach cancer (SIR=1.37, 95% CI 1.11 to 1.63), liver cancer (SIR=1.70, 95% CI 1.16 to 2.25) and rectal cancer (SIR=1.41, 95% CI 1.16 to 1.66). The SIR was elevated for all leukaemias (SIR=1.51, 95% CI 1.08 to 2.07) and for lymphatic and haematopoietic cancers combined (SIR=1.31, 95% CI 1.05 to 1.61), but results for specific subtypes were imprecise. Deaths due to hazardous mining conditions resulted in 0.33 person-years of life lost per miner.
Conclusions Occupational exposure to the Příbram mines resulted in excess cancers at several sites, including sites previously linked to radon and uranium exposure. Incidence analyses showed relative excess of several additional cancer subtypes.
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Contributor DPS and DS made substantial contributions to the conceptionof this work. KKR, DBR, DPS and DS led the initial design of this analysis. KKR led the data analysis and manuscript writing. All authors reviewed and made substantial contributions to the analysis plan and manuscript drafts. All authorsreviewed and approved the final version of the manuscript for publication.
Funding This work was funded in part by the Intramural Research Program of the NIH, National Institute of Environmental Health Sciences (Z01-ES049028). This work was also supported by the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention (T42-OH008673).
Disclaimer The findings and conclusions of this report are those of the authors and do not necessarily reflect those of the National Institute for Occupational Safety and Health.
Competing interests None declared.
Ethics approval The study protocol was reviewed by the Institutional Review Boards (IRBs) at the NIEHS and UNC Chapel Hill and determined to be exempt from full IRB review, as it involved existing records and deidentified data.
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent for publication Not required.
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