The present findings show an excess mortality from lung cancer due to radon exposure and from solid cancers due to external gamma radiation in uranium millers that was not statistically significant. Exposure to uranium was not associated with any cause of death, but absorbed organ doses were estimated to be low.

It is currently unclear whether exposure of the heart and vascular system, at lifetime accumulated dose levels relevant to the general public (<500 mGy), is associated with an increased risk of cardiovascular disease. Therefore, data from the German WISMUT cohort of uranium miners were investigated for evidence of a relationship between external gamma radiation and death from cardiovascular diseases. The cohort comprises 58,982 former employees of the Wismut company. There were 9,039 recorded deaths from cardiovascular diseases during the follow-up period from 1946 to 2008. Exposures to external gamma radiation were estimated using a detailed job-exposure matrix. The exposures were based on expert ratings for the period 1946-1954 and measurements thereafter. The excess relative risk (ERR) per unit of cumulative gamma dose was obtained with internal Poisson regression using a linear ERR model with baseline stratification by age and calendar year. The mean cumulative gamma dose was 47 mSv for exposed miners (86 %), with a maximum of 909 mSv. No evidence for an increase in risk with increasing cumulative dose was found for mortality from all cardiovascular diseases (ERR/Sv = -0.13; 95 % confidence interval (CI): -0.38; 0.12) and ischemic heart diseases (n = 4,613; ERR/Sv = -0.03; 95 % CI: -0.38, 0.32). However, a statistically insignificant increase (n = 2,073; ERR/Sv = 0.44; 95 % CI: -0.16, 1.04) for mortality from cerebrovascular diseases was observed. Data on smoking, diabetes, and overweight are available for subgroups of the cohort, indicating no major correlation with cumulative gamma radiation. Confounding by these factors or other risk factors, however, cannot be excluded. In conclusion, the results provide weak evidence for an increased risk of death due to gamma radiation only for cerebrovascular diseases.

Background:In 1996 and 2009, the International Agency for Research on Cancer classified silica as carcinogenic to humans. The exposure–response relationship between silica and lung cancer risk, however, is still debated. Data from the German uranium miner cohort study were used to further investigate this relationship.Methods:The cohort includes 58 677 workers with individual information on occupational exposure to crystalline silica in mg m−3-years and the potential confounders radon and arsenic based on a detailed job-exposure matrix. In the follow-up period 1946–2003, 2995 miners died from lung cancer. Internal Poisson regression with stratification by age and calendar year was used to estimate the excess relative risk (ERR) per dust-year. Several models including linear, linear quadratic and spline functions were applied. Detailed adjustment for cumulative radon and arsenic exposure was performed.Results:A piecewise linear spline function with a knot at 10 mg m−3-years provided the best model fit. After full adjustment for radon and arsenic no increase in risk <10 mg m−3-years was observed. Fixing the parameter estimate of the ERR in this range at 0 provided the best model fit with an ERR of 0.061 (95% confidence interval: 0.039, 0.083) >10 mg m−3-years.Conclusion:The study confirms a positive exposure–response relationship between silica and lung cancer, particularly for high exposures.

The Wismut cohort is currently the largest single study on the health risks associated with occupational exposures to ionising radiation and dust accrued during activities related to uranium mining. The cohort has ∼59 000 male workers, first employed between 1946 and 1989, at the Wismut Company in Germany. The main effect is a statistically significant increase in mortality from lung cancer with both increasing cumulative radon exposure and silica dust exposure. Risks for cancers of the extrathoracic airways, all extra-pulmonary cancers and cardiovascular diseases associated with radiation exposures have been evaluated. Cohort mortality rates for some other cancer sites, stomach and liver, are statistically significantly increased in relation to the general population, but not statistically significantly related to occupational exposures. No associations between leukaemia mortality and occupational doses of ionising radiation were found.

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