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Home > ... > ... > Related Wismut Studies of the BfS
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Related Wismut Studies of the BfS
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Pooled European Study: Alpha-Risk
Nested case-control study on lung cancer
Study on offsprings of Wismut workers
Study on molecular effects
Within the EU-alpha-risk project the French, Czech and German cohort studies on former uranium miners are investigated with respect to the cancer risk due to low radiation exposure. Moreover, organ doses for several organs and the corresponding risks are calculated. The Wismut cohort data based on the first mortality follow-up by 1998 restricted to sub-cohort B and C (begin of employment after 1954) are included in the EU-alpha risk project.
With respect to lung cancer among miners, exposure to radon and its progeny is a major risk factor. However, there exist more factors, which have to be taken into account in the risk assessment. The most important factor is smoking. Furthermore there are factors like occupational exposure to other carcinogenic substances like arsenic and asbestos. Information on smoking habits and on the occupational exposure from jobs outside the Wismut are only scarcely available for the complete cohort (n=59,000 miners). For that reason, information on the lifelong smoking habits and on the exposure to occupational carcinogenic substances for jobs outside the Wismut was collected for a subset of 700 deaths from lung cancer (“cases”) and for 1,400 individuals which did not die on lung cancer (“controls”) from the Wismut cohort. The information was either obtained in interviews with the members of the study, or—in the case of death—with their relatives and, on the other hand, from investigations in the files of the former
health archive of the Wismut.
First results
As in the Wismut cohort information on smoking habits is either available only sporadically or very imprecise whence, up to now, smoking could not be taken into account in the assessment of the risk of lung cancer due to radon. However if smoking were correlated with the exposure to radon at work, then theoretically this could lead to an under- or over-estimation of the true risk of radon-induced lung cancer death. For 421 cases and 620 controls of the case-control study the smoking habits could be reconstructed. The statistical analysis of this data-basis did not differ considerably in the assessment of the lung cancer risk due to radon with and without adjustment of the smoking habits. E. g., the risk increased by 0.23% per WLM with adjustment of the smoking habits and by 0.25% without adjustment. Therefore smoking seems not to represent a major confounder for the estimation of the risk of radon induced lung cancer in the Wismut cohort. This part of the study was funded by the European Commission and has been published in Health Physics in 2010 (Schnelzer et al, 2010
).
The question of whether a high radiation exposure of the fathers may result in health damages in the offspring is a point of controversial scientific discussion. A Canadian study gives weak indications for an increased risk of leukemia for children of uranium miners. To address the question of possible genetic effects, the BfS conducted a feasibility study for a cohort study with about 7,000 children of uranium miners. However, a first analysis of the data did show a series of methodological problems, which would strongly reduce the significance of the study. This includes a high percentage of missing causes of death for the deceased offspring, especially for years of death between 1950 and 1970, a non negligible fraction of children which could not be located and a relatively low exposure of the gonads of the employees of the Wismut before the conception of the children. Due to these methodological problems it was decided not to carry out the main cohort study.
As a new focus within the frame of the uranium miners cohort study is the investigation of molecular effects of radiation and of other noxious substances. To that end, several scientific studies were set up in 2007 in which biological material (for example, blood samples or tissue samples from autopsies) of former Wismut employees are collected. The points of special interest are:
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Assessment of the individual sensitivity to radiation in individuals which develop lung cancer at very young age.
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Identification of potential bio-markers for the exposure to arsenic and/or radon using proteomics and cDNA micro-array technologies.
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Investigation of molecular signatures of a combined exposure to several harmful substances.
Objectives of the study:
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Gain a deeper understanding of the association between ionizing radiation and the incidence of cancers and of the underlying effects on a molecular scale.
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Foundation of the scientific basics for the assessment of health damages in uranium mining.
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Establishment of a basis for the derivation of efficient means of protection against the risks of radon both for miners and for the pre-emptive protection of the total population, for example, against increased levels of radon in homes.
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