Bernd Grosche

Radon, smoking and lung cancer risk: results of a joint analysis of three European case-control studies among uranium miners.

A combined analysis of three case-control studies nested in three European uranium miner cohorts was performed to study the joint effects of radon exposure and smoking on lung cancer death risk. Occupational history and exposure data were available from the cohorts. Smoking information was reconstructed using self-administered questionnaires and occupational medical archives. Linear excess relative risk models adjusted for smoking were used to estimate the lung cancer risk associated with radon exposure. The study includes 1046 lung cancer cases and 2492 controls with detailed radon exposure data and smoking status. The ERR/WLM adjusted for smoking is equal to 0.008 (95% CI: 0.004–0.014). Time since exposure is shown to be a major modifier of the relationship between radon exposure and lung cancer risk. Fitting geometric mixture models yielded arguments in favor of a sub-multiplicative interaction between radon and smoking. This combined study is the largest case-control study to investigate the joint effects of radon and smoking on lung cancer risk among miners. The results confirm that the lung carcinogenic effect of radon persists even when smoking is adjusted for, with arguments in favor of a sub-multiplicative interaction between radon and smoking.

Mortality among US commercial pilots and navigators

The airline industry may be an occupational setting with specific health risks. Two environmental agents to which flight crews are known to be exposed are cosmic radiation and magnetic fields generated by the aircrafts electrical system. Other factors to be considered are circadian disruption and conditions specific to air travel, such as noise, vibration, mild hypoxia, reduced atmospheric pressure, low humidity, and air quality. This study investigated mortality among US commercial pilots and navigators, using proportional mortality ratios for cancer and noncancer end points. Proportional cancer mortality ratios and mortality odds ratios were also calculated for comparison to the proportional mortality ratios for cancer causes of death. Results indicated that US pilots and navigators have experienced significantly increased mortality due to cancer of the kidney and renal pelvis, motor neuron disease, and external causes. In addition, increased mortality due to prostate cancer, brain cancer, colon cancer, and cancer of the lip, buccal cavity, and pharynx was suggested. Mortality was significantly decreased for 11 causes. To determine if these health outcomes are related to occupational exposures, it will be necessary to quantify each exposure separately, to study the potential synergy of effects, and to couple this information with disease data on an individual basis.

Radiation Exposure due to Local Fallout from Soviet Atmospheric Nuclear Weapons Testing in Kazakhstan: Solid Cancer Mortality in the Semipalatinsk Historical Cohort, 1960–1999

Abstract Bauer, S., Gusev, B. I., Pivina, L. M., Apsalikov, K. N. and Grosche, B. Radiation Exposure due to Local Fallout from Soviet Atmospheric Nuclear Weapons Testing in Kazakhstan: Solid Cancer Mortality in the Semipalatinsk Historical Cohort, 1960–1999. Radiat. Res. 164, 409–419 (2005). Little information is available on the health effects of exposures to fallout from Soviet nuclear weapons testing and on the combined external and internal environmental exposures that have resulted from these tests. This paper reports the first analysis of the Semipalatinsk historical cohort exposed in the vicinity of the Semipalatinsk nuclear test site, Kazakhstan. The cohort study, which includes 19,545 inhabitants of exposed and comparison villages of the Semipalatinsk region, was set up in the 1960s and comprises 582,750 person-years of follow-up between 1960 and 1999. Cumulative effective radiation dose estimates in this cohort range from 20 mSv to ∼4 Sv. Rates of mortality and cancer mortality in the exposed group substantially exceeded those of the comparison group. Dose–response analyses within the exposed group confirmed a significant trend with dose for all solid cancers (P < 0.0001) and for digestive and respiratory cancers (P = 0.0255 and P < 0.0001), whereas no consistent dose–response trend was found for all causes of death (P = 0.4296). Regarding specific cancer sites, a significant trend with dose was observed for lung cancer (P = 0.0001), stomach cancer (P = 0.0050), and female breast cancer (P = 0.0040) as well as for esophagus cancer in women (P = 0.0030). The excess relative risk per sievert for all solid cancers combined was 1.77 (1.35; 2.27) based on the total cohort data, yet a selection bias regarding the comparison group could not be entirely ruled out. The excess relative risk per sievert based on the cohorts exposed group was 0.81 (0.46; 1.33) for all solid cancers combined and thus still exceeds current risk estimates from the Life Span Study. Future epidemiological assessments based on this cohort will benefit from extension of follow-up and ongoing validation of dosimetric data.

Histopathologic findings of lung carcinoma in German uranium miners

This study evaluates the histopathology of lung carcinoma in relation to underground radon exposure.

Accounting For Smoking In The Radon-related Lung Cancer Risk Among German Uranium Miners: Results Of A Nested Case-control Study

The possible confounding effect of smoking on radon-associated risk for lung cancer mortality was investigated in a case-control study nested in the cohort of German uranium miners. The study included 704 miners who died of lung cancer and 1,398 controls matched individually for birth year and attained age. Smoking status was reconstructed from questionnaires and records from the mining company’s health archives for 421 cases and 620 controls. Data on radon exposure were taken from a job-exposure matrix. Smoking adjusted odds ratios for lung cancer in relation to cumulative radon exposure have been calculated with conditional logistic regression. The increase in risk per Working Level Month (WLM) was assessed with a linear excess relative risk (ERR) model taking smoking into account as a multiplicative factor. In addition, the potential impact of temporal factors on the ERR per WLM was examined. Lung cancer mortality risk increased with increasing radon exposure, yielding a crude ERR per WLM of 0.25% (95% CI: 0.13–0.46%). Adjustment for smoking led only to marginal changes of the radon-associated lung cancer risks. The adjusted ERR per WLM was very similar (0.23%, 95%-CI: 0.11–0.46%) to the crude risk and to the risk found in the Wismut cohort study. This stability of the radon-related lung cancer risks with and without adjustment for smoking suggests that smoking does not act as a major confounder in this study and presumably also not in the cohort study.

The Influence of Radon Exposures on Lung Cancer Mortality in German Uranium Miners, 1946–2003

Abstract Extensive uranium extraction took place from 1946 until 1990 at the former Wismut mining company in East Germany. A total of 58,987 male former employees of this company form the largest single uranium miners cohort that has been followed up for causes of mortality occurring from the beginning of 1946 to the end of 2003. The purpose of this study was to investigate and evaluate different forms of models for the radon exposure-related lung cancer mortality risk based on 3,016 lung cancer deaths and 2 million person years. Other exposure covariables such as occupational exposure to external γ radiation, long-lived radionuclides, arsenic, fine dust and silica dust are available. The standardized mortality ratio for lung cancer is 2.03 (95% CI: 1.96; 2.10). The simple cohort excess relative risk (ERR/WLM) for lung cancer is estimated as 0.0019 (95% CI: 0.0016; 0.0022). The BEIR VI model produced risks similar to those obtained with a selected mathematically continuous ERR model for lung cancer. The continuous model is linear in radon exposure with exponential effect modifiers that depend on the whole range of age at median exposure, time since median exposure, and radon exposure rate. In this model the central estimate of ERR/WLM is 0.0054 (95% CI: 0.0040; 0.0068) for an age at median exposure of 30 years, a time since median exposure of 20 years, and a mean exposure rate of 3 WL. The ERR decreases by 5% for each unit of exposure-rate increase. The ERR decreases by 28% with each decade increase in age at median exposure and also decreases by 51% with each decade increase in time since median exposure. The method of determination of radon exposure (i.e., whether the exposures were estimated or measured) did not play an important role in the determination of the ERR. The other exposure covariables were found to have only minor confounding influences on the ERR/WLM for the finally selected continuous model when included in an additive way.

Thyroid Cancer after Diagnostic Administration of Iodine-131 in Childhood

Abstract Hahn, K., Schnell-Inderst, P., Grosche, B. and Holm, L-E. Thyroid Cancer after Diagnostic Administration of Iodine-131 in Childhood. Radiat. Res. 156, 61–70 (2001). To determine the carcinogenic effects of diagnostic amounts of 131I on the juvenile thyroid gland, a multicenter retrospective cohort study was conducted on 4,973 subjects who either had been referred for diagnostic tests using uptake of 131I (n = 2,262) or had had a diagnostic procedure on the thyroid without 131I (n = 2,711) before the age of 18 years. Follow-up examinations were conducted after a mean period of 20 years after the first examination in 35% of the exposed subjects (n = 789) and in 41% of the nonexposed subjects (n = 1,118). Iodine-131 dosimetry of the thyroid was carried out according to ICRP Report No 53, and the median thyroid dose was 1.0 Gy. In the exposed group, two thyroid cancers were found during 16,500 person-years, compared to three cancers in the nonexposed group during 21,000 person-years. The relative risk for the exposed group was 0.86 (95% CI: 0.14–5.13). The study did not demonstrate an increased risk for thyroid cancer after administration of 131I in childhood.

Cancer consequences of the Chernobyl accident in Europe outside the former USSR : A review

The accident which occurred during the night of April 25–26, 1986 in reactor 4 of the Chernobyl nuclear power plant in the Ukraine released considerable amounts of radioactive substances into the environment. Outside the former USSR, the highest levels of contamination were recorded in Bulgaria, Austria, Greece and Romania, followed by other countries of Central, Southeast and Northern Europe. Studies of the health consequences of the accident have been carried out in these countries, as well as in other countries in Europe. This report presents the results of a critical review of cancer studies of the exposed population in Europe, carried out on the occasion of the 10th anniversary of the Chernobyl accident. Overall, there is no evidence to date of a major public health impact of the Chernobyl accident in the field of cancer in countries of Europe outside the former USSR.

Dose and dose-rate effects of ionizing radiation: a discussion in the light of radiological protection

Abstract The biological effects on humans of low-dose and low-dose-rate exposures to ionizing radiation have always been of major interest. The most recent concept as suggested by the International Commission on Radiological Protection (ICRP) is to extrapolate existing epidemiological data at high doses and dose rates down to low doses and low dose rates relevant to radiological protection, using the so-called dose and dose-rate effectiveness factor (DDREF). The present paper summarizes what was presented and discussed by experts from ICRP and Japan at a dedicated workshop on this topic held in May 2015 in Kyoto, Japan. This paper describes the historical development of the DDREF concept in light of emerging scientific evidence on dose and dose-rate effects, summarizes the conclusions recently drawn by a number of international organizations (e.g., BEIR VII, ICRP, SSK, UNSCEAR, and WHO), mentions current scientific efforts to obtain more data on low-dose and low-dose-rate effects at molecular, cellular, animal and human levels, and discusses future options that could be useful to improve and optimize the DDREF concept for the purpose of radiological protection.

Risk of Childhood Leukaemia in the Vicinity of Nuclear Installations Findings and Recent Controversies

The identification of a local excess of cancer cases, possibly associated with ionizing radiation, always receives substantial media coverage and communication about clusters is difficult. We reviewed studies that examined the risk of leukaemia among young people near nuclear installations. An excess of leukaemia exists near some nuclear installations, at least for the reprocessing plants at Sellafield and Dounreay and the nuclear power plant Kru¨mmel. Nonetheless, the results of multi-site studies invalidate the hypothesis of an increased risk of leukaemia related to nuclear discharge. Up until now, analytic studies have not found an explanation for the leukaemia clusters observed near certain nuclear installations. The hypothesis of an infectious aetiology associated with population mixing has been proposed, but needs to be investigated further. The review illustrates two recent examples in France (La Hague reprocessing plant) and in Germany (Kru¨mmel power plant), where controversies developed after reports of increased leukaemia risks. These examples show the importance of recalling the current epidemiological knowledge and of using systematic recording of cases to replace the alleged excesses in a more general framework. Some elements should also be suggested from the recent French and German experiences to reinforce credibility in the results.