Childhood leukemia near nuclear sites in Belgium: An ecological study at small geographical level.

BACKGROUND: A previous investigation of the occurrence of childhood acute leukemia around the Belgian nuclear sites has shown positive associations around one nuclear site (Mol-Dessel). In the following years, the Belgian Cancer Registry has made data available at the smallest administrative unit for which demographic information exists in Belgium, i.e. the statistical sector. This offers the advantage to reduce the potential misclassification due to large geographical scales. METHODS: The current study performed for the period 2006-2016 uses Poisson models to investigate (i) the incidence of childhood acute leukemia within 20 km around the four Belgian nuclear sites, (ii) exposure-response relationships between cancer incidence and surrogate exposures from the nuclear sites (distance, wind direction frequency and exposure by hypothetical radioactive discharges taking into account historical meteorological conditions). All analyses are carried out at statistical sector level. RESULTS: Higher incidence rate ratios were found for children <15 years (7 cases, RR = 3.01, 95% CI: 1.43;6.35) and children <5 years (< 5 cases, RR = 3.62, 95% CI: 1.35;9.74) living less than 5 km from the site of Mol-Dessel. In addition, there was an indication for positive exposure-response relationships with the different types of surrogate exposures. CONCLUSION: Results confirm an increased incidence of acute childhood leukemia around Mol-Dessel, but the number of cases remains very small. Random variation cannot be excluded and the ecological design does not allow concluding on causality. These findings emphasize the need for more in-depth research into the risk factors of childhood leukemia, for a better understanding of the etiology of this disease.

Introduction of a method to calculate cumulative age- and gender-specific lifetime attributable risk (LAR) of cancer in populations after a large-scale nuclear power plant accident.

The effect of age and gender in risk estimates related to long-term residence in areas contaminated by nuclear power plant fallout was evaluated by applying the lifetime attributable risk (LAR) concept to an existing exposure model that was previously used for cumulative effective dose estimates. In this study, we investigated the influence of age distribution on the number of cancer cases by applying five different age distributions from nuclear power-producing countries (India, Japan, South Korea, and the United States), and Egypt because of intentions to develop nuclear power. The model was also used to estimate the effective dose and gender-specific LAR as a function of time after fallout for the offspring of the population living in 137Cs fallout areas. The principal findings of this study are that the LAR of cancer incidence (excluding non-fatal skin cancers) over 70 y is about 4.5 times higher for newborn females (5.4% per MBq m-2 of initial 137Cs ground deposition) than the corresponding values for 30 y old women (1.2% per MBq m-2 137Cs deposition). The cumulative LAR for newborn males is more than 3 times higher (3.2% versus 1.0% per MBq m-2 137Cs deposition). The model predicts a generally higher LAR for women until 50 y of age, after which the gender difference converges. Furthermore, the detriment for newborns in the fallout areas initially decreases rapidly (about threefold during the first decade) and then decreases gradually with an approximate half-time of 10-12 y after the first decade. The age distribution of the exposed cohort has a decisive impact on the average risk estimates, and in our model, these are up to about 65% higher in countries with high birth rates compared to low birth rates. This trend implies larger average lifetime attributable risks in countries with a highly proportional younger population. In conclusion, the large dispersion (up to a factor of 4 between newborns and 30 y olds) in the lifetime detriment per unit ground deposition of 137Cs over gender and age in connection with accidental nuclear releases justifies the effort in developing risk models that account for the higher radiation sensitivity in younger populations.

Thyroid cancer incidence near nuclear sites in Belgium: An ecological study at small geographical level.

In Belgium, variations in thyroid cancer incidence were observed around the major nuclear sites. The present ecological study investigates whether there is an excess incidence of thyroid cancer among people living in the vicinity of the four nuclear sites at the smallest Belgian geographical level. Rate ratios were obtained from a Bayesian hierarchical model for areas of varying sizes around the nuclear sites. Focused hypothesis tests and generalized additive models were performed to test the hypothesis of a gradient in thyroid cancer incidence with increasing levels of surrogate exposures. No evidence was found for more incident cases of thyroid cancer near the two nuclear power plants. Regarding the two industrial and research nuclear sites, no evidence for a higher incidence in the vicinity of Mol-Dessel was observed, whereas a slightly nonsignificant higher incidence was found in the close vicinity of Fleurus. In addition, significant gradients for thyroid cancer incidence were observed with the different types of surrogate exposure considered in the 20 km area around the site of Fleurus (decreasing distance, increasing wind direction frequency and increasing exposure to estimated hypothetical radioactive discharges of iodine-131). In the investigation at the smallest Belgian geographical level, variations in thyroid cancer incidence were found around the Belgian nuclear sites. Significant exposure-response relationships were also observed for the site of Fleurus. Further investigations into these findings could be useful to allow inferring causal relationships on the origin of variations in incidence and to provide information at the individual level.

Mortality of older construction and craft workers employed at department of energy nuclear sites: Follow-up through 2016.

BACKGROUND: To determine if construction and trades workers employed at U.S. Department of Energy (DOE) nuclear sites facilities are at significant risk for diseases associated with occupational exposures, we compared the mortality experience of participants in the Building Trades National Medical Screening Program (BTMed) to that of the US population. METHODS: The cohort includes 24,086 BTMed participants enrolled between 1998 and 2016 and 5203 deaths. Cause-specific standardized mortality ratios were calculated based on US death rates. RESULTS: Mortality was elevated for all causes, all cancers, cancers of the trachea, bronchus, and lung and lymphatic and hematopoietic system, mesothelioma, chronic obstructive pulmonary disease, asbestosis, transportation injuries, and other injuries, particularly those caused by accidental poisoning, suggesting a possible effect of the opioid epidemic. CONCLUSIONS: Apart from other injuries, mortality patterns were very similar to those reported in the past in this population. Construction workers employed at DOE sites have a significantly increased risk for occupational illnesses. Risks are associated with employment during all time periods covered including possibly after 1990. The cancer risks closely match the cancers identified for DOE compensation from radiation exposures. The high risk of lung cancer supports the value of early lung cancer detection. Continued medical surveillance is important.

ANALYSIS OF THE RADIOLOGICAL SAFETY CONTROL LEVEL VERSUS THE EXPOSURE OF RADIATION WORKERS IN SOUTH KOREA FROM 2008-17.

In this study, the radiation exposure of workers at workplaces registered and licensed between 2008 and 2017 for the production/sale/use of radioactive isotopes (RI) and radioactive generators (RG) was analysed to evaluate the quality of radiation safety management controls in use. The number of facilities using RIs increased by ~26% from 2008 to 2017 whereas the number of facilities using RGs increased by ~166% over the same period. There were 33 029 radiation workers in all fields in 2008, and the number increased by ~32% to 43 467 by 2017. However, the collective effective dose of radiation received by workers decreased in all industries except for those working in nuclear power plants. In other words, the quality of radiation safety management improved over that same time period due to the systematic, continuous introduction of safety mechanisms by the regulatory authority.

Reanalysis of Epidemiological Investigation of Cancer Risk among People Residing near Nuclear Power Plants in South Korea.

Background: A 20-year follow-up study on cancer incidence among people living near nuclear power plants in South Korea ended in 2011 with a finding of significantly, but inconsistently, elevated thyroid cancer risk for females. Reanalysis of the original study was carried out to examine the dose-response relationship further, and to investigate any evidence of detection bias. Methods: In addition to replicating the original Cox proportional hazards models, nested case-control analysis was carried out for all subjects and for four different birth cohorts to examine the effects of excluding participants with pre-existing cancer history at enrollment. The potential for detection bias was investigated using the records of medical utilization and voluntary health checks of comparison groups. Results: The overall risk profile of the total sample was similar to that of the original study. However, in the stratified analysis of four birth cohorts, the cancer risk among people living near nuclear power plants became higher in younger birth cohorts. This was especially true for thyroid cancers of females (hazard ratio (HR) 3.38) and males (HR 1.74), female breast cancers (HR 2.24), and radiation-related cancers (HR 1.59 for males, HR 1.77 for females), but not for radiation-insensitive cancers (HR 0.59 for males, HR 0.98 for females). Based on medical records and health check reports, we found no differences between comparison groups that could have led to detection bias. Conclusions: The overall results suggest elevated risk of radiation-related cancers among residents living near nuclear power plants, controlling for the selective survival effect. This is further supported by the lack of evidence of detection bias and by records of environmental exposure from radiation waste discharge.

Impact of considering non-occupational radiation exposure on the association between occupational dose and solid cancer among French nuclear workers.

OBJECTIVES: The French nuclear worker cohort allows for the assessment of cancer risk associated with occupational radiation exposure, but workers are also exposed to medical and environmental radiation which can be of the same order of magnitude. This study aims to examine the impact of non-occupational radiation exposures on the dose-risk analysis between occupational radiation exposure and cancer mortality. METHODS: The cohort included workers employed before 1995 for at least one year by CEA, AREVA NC or EDF and badge-monitored for external radiation exposure. Monitoring results were used to calculate occupational individual doses. Scenarios of work-related X-ray and environmental exposures were simulated. Poisson regression was used to quantify associations between occupational exposure and cancer mortality adjusting for non-occupational radiation exposure. RESULTS: The mean cumulative dose of external occupational radiation was 18.4 mSv among 59 004 workers. Depending on the hypotheses made, the mean cumulative work-related X-ray dose varied between 3.1 and 9.2 mSv and the mean cumulative environmental dose was around 130 mSv. The unadjusted excess relative rate of cancer per Sievert (ERR/Sv) was 0.34 (90% CI -0.44 to 1.24). Adjusting for environmental radiation exposure did not substantially modify this risk coefficient, but it was attenuated by medical exposure (ERR/Sv point estimate between 0.15 and 0.23). CONCLUSIONS: Occupational radiation risk estimates were lower when adjusted for work-related X-ray exposures. Environmental exposures had a very slight impact on the occupational exposure risk estimates. In any scenario of non-occupational exposure considered, a positive but insignificant excess cancer risk associated with occupational exposure was observed.

Mortality from Circulatory Diseases and other Non-Cancer Outcomes among Nuclear Workers in France, the United Kingdom and the United States (INWORKS).

Positive associations between external radiation dose and non-cancer mortality have been found in a number of published studies, primarily of populations exposed to high-dose, high-dose-rate ionizing radiation. The goal of this study was to determine whether external radiation dose was associated with non-cancer mortality in a large pooled cohort of nuclear workers exposed to low-dose radiation accumulated at low dose rates. The cohort comprised 308,297 workers from France, United Kingdom and United States. The average cumulative equivalent dose at a tissue depth of 10 mm [Hp(10)] was 25.2 mSv. In total, 22% of the cohort were deceased by the end of follow-up, with 46,029 deaths attributed to non-cancer outcomes, including 27,848 deaths attributed to circulatory diseases. Poisson regression was used to investigate the relationship between cumulative radiation dose and non-cancer mortality rates. A statistically significant association between radiation dose and all non-cancer causes of death was observed [excess relative risk per sievert (ERR/Sv) = 0.19; 90% CI: 0.07, 0.30]. This was largely driven by the association between radiation dose and mortality due to circulatory diseases (ERR/Sv = 0.22; 90% CI: 0.08, 0.37), with slightly smaller positive, but nonsignificant, point estimates for mortality due to nonmalignant respiratory disease (ERR/Sv = 0.13; 90% CI: -0.17, 0.47) and digestive disease (ERR/Sv = 0.11; 90% CI: -0.36, 0.69). The point estimate for the association between radiation dose and deaths due to external causes of death was nonsignificantly negative (ERR = -0.12; 90% CI: <-0.60, 0.45). Within circulatory disease subtypes, associations with dose were observed for mortality due to cerebrovascular disease (ERR/Sv = 0.50; 90% CI: 0.12, 0.94) and mortality due to ischemic heart disease (ERR/Sv = 0.18; 90% CI: 0.004, 0.36). The estimates of associations between radiation dose and non-cancer mortality are generally consistent with those observed in atomic bomb survivor studies. The findings of this study could be interpreted as providing further evidence that non-cancer disease risks may be increased by external radiation exposure, particularly for ischemic heart disease and cerebrovascular disease. However, heterogeneity in the estimated ERR/Sv was observed, which warrants further investigation. Further follow-up of these cohorts, with the inclusion of internal exposure information and other potential confounders associated with lifestyle factors, may prove informative, as will further work on elucidating the biological mechanisms that might cause these non-cancer effects at low doses.

Radiation exposure and lung disease in today's nuclear world.

PURPOSE OF REVIEW: Ionizing radiation poses important health risks. The per capita annual dose rate has increased in the United States and there is increasing concern for the risks posed by low-dose occupational exposure among workers in nuclear industries and healthcare. Recent nuclear accidents and concern for terrorism have heightened concern for catastrophic, high-dose ionizing radiation exposure. This review will highlight recent research into the risks to lung health posed by ionizing radiation exposure and into potential treatments. RECENT FINDINGS: Angiotensin-converting enzyme inhibitors and some antioxidants have shown promise as mitigators, to decrease pneumonitis and fibrosis when given after exposure. Studies of survivors of nuclear catastrophes have shown increased risk for lung cancer, especially in nonsmokers. There is evidence for increased lung cancer risk in industrial radiation workers, especially those who process plutonium and may inhale radioactive particles. There does not seem to be an increased risk of lung cancer in healthcare workers who perform fluoroscopic procedures. SUMMARY: High-dose ionizing radiation exposure causes pneumonitis and fibrosis, and more research is needed to develop mitigators to improve outcomes in nuclear catastrophes. Long-term, low-dose occupational radiation may increase lung cancer risk. More research to better define this risk could lead to improved safety protocols and screening programs.

Commercial Nuclear Power Industry: Assessing and Meeting the Radiation Protection Workforce Needs.

This paper will provide an overview of the process used by the commercial nuclear power industry in assessing the status of existing industry staffing and projecting future supply demand needs. The most recent Nuclear Energy Institute-developed "Pipeline Survey Results" will be reviewed with specific emphasis on the radiation protection specialty. Both radiation protection technician and health physicist specialties will be discussed. The industry-initiated Nuclear Uniform Curriculum Program will be reviewed as an example of how the industry has addressed the need for developing additional resources. Furthermore, the reality of challenges encountered in maintaining the needed number of health physicists will also be discussed.

[Effects on health of the Chernobyl accident: 30 years on]. / Gesundheitliche Folgen des Unfalls von Tschernobyl - 30 Jahre danach.

This paper reflects the current state of research into the short- and long-term effects on health in the former Soviet Union and Europe of the nuclear accident in Chernobyl. It discusses the latest results of epidemiological studies and presents future research perspectives.

Managing Groundwater Radioactive Contamination at the Daiichi Nuclear Plant.

The Great East Japan Earthquake and tsunami of March 2011 severely damaged three reactors at the Fukushima Daiichi nuclear power station, leading to a major release of radiation into the environment. Groundwater flow through these crippled reactors continues to be one of the main causes of contamination and associated transport of radionuclides into the Pacific Ocean. In this context, a number of strategies are being implemented to manage radioactive pollution of the water resources at the nuclear plant site. Along with water treatment and purification, it is critical to restrict the groundwater flow to and from the reactors. Thus, the devised strategies combine walls containment, bores abstraction, infiltration control, and the use of tanks for the temporary storage of contaminated waters. While some of these techniques have been previously applied in other environments, they have never been tested at such a large scale. Therefore, their effectiveness remains to be seen. The present manuscript presents an overview of the methods being currently implemented to manage groundwater contamination and to mitigate the impact of hydrological pathways in the dispersion of radionuclides at Fukushima.

Pooled Bayesian meta-analysis of two Polish studies on radiation-induced cancers.

The robust Bayesian regression method was applied to perform meta-analysis of two independent studies on influence of low ionising radiation doses on the occurrence of fatal cancers. The re-analysed data come from occupational exposure analysis of nuclear workers in Swierk (Poland) and from ecological study of cancer risk from natural background radiation in Poland. Such two different types of data were analysed, and three popular models were tested: constant, linear and quadratic dose-response dependencies. The Bayesian model selection algorithm was used for all models. The Bayesian statistics clearly indicates that the popular linear no-threshold (LNT) assumption is not valid for presented cancer risks in the range of low doses of ionising radiation. The subject of LNT hypothesis use in radiation risk prediction and assessment is also discussed.

Mortality of older construction and craft workers employed at department of energy (DOE) nuclear sites: follow-up through 2011.

BACKGROUND: The Building Trades National Medical Screening Program (BTMed) was established in 1996 to provide occupational medicine screening examinations for construction workers who have worked at US Department of Energy nuclear sites. Workers participating in BTMed between 1998 and 2011 were followed to determine their vital status and mortality experience through December 31, 2011. METHODS: The cohort includes 18,803 BTMed participants and 2,801 deaths. Cause-specific Standardized Mortality Ratios (SMRs) were calculated based on US death rates. RESULTS: Mortality was elevated for all causes, all cancers, cancers of the trachea, bronchus, and lung and lymphatic and hematopoietic system, mesothelioma, COPD, and asbestosis. CONCLUSIONS: Construction workers employed at DOE sites have a significantly increased risk for occupational illnesses. Risks are associated with employment during all time periods covered including after 1980. The cancer risks closely match the cancers identified for DOE compensation from radiation exposures. Continued medical surveillance is important.

Reduction factors for wooden houses due to external γ-radiation based on in situ measurements after the Fukushima nuclear accident.

For estimation of residents' exposure dose after a nuclear accident, the reduction factor, which is the ratio of the indoor dose to the outdoor dose is essential, as most individuals spend a large portion of their time indoors. After the Fukushima nuclear accident, we evaluated the median reduction factor with an interquartile range of 0.43 (0.34-0.53) based on 522 survey results for 69 detached wooden houses in two evacuation zones, Iitate village and Odaka district. The results indicated no statistically significant difference in the median reduction factor to the representative value of 0.4 given in the International Atomic Energy Agency (IAEA)-TECDOC-225 and 1162. However, with regard to the representative range of the reduction factor, we recommend the wider range of 0.2 to 0.7 or at least 0.2 to 0.6, which covered 87.7% and 80.7% of the data, respectively, rather than 0.2 to 0.5 given in the IAEA document, which covered only 66.5% of the data. We found that the location of the room within the house and area topography, and the use of cement roof tiles had the greatest influence on the reduction factor.

A reanalysis of cancer mortality in Canadian nuclear workers (1956-1994) based on revised exposure and cohort data.

BACKGROUND: A 15-country study of nuclear workers reported significantly increased radiation-related risks of all cancers excluding leukaemia, with Canadian data a major factor behind the pooled results. We analysed mortality (1956-1994) in the updated Canadian cohort and provided revised risk estimates. METHODS: Employment records were searched to verify and revise exposure data and to restore missing socioeconomic status. Excess relative risks per sievert (ERR/Sv) of recorded radiation dose and 95% confidence intervals (CIs) were estimated using Poisson regression. RESULTS: A significant heterogeneity of the dose-response for solid cancer was identified (P=0.02), with 3088 early (1956-1964) Atomic Energy of Canada Limited (AECL) workers having a significant increase (ERR/Sv=7.87, 95% CI: 1.88, 19.5), and no evidence of radiation risk for 42,228 workers employed by three nuclear power plant companies and post-1964 AECL (ERR/Sv=-1.20, 95% CI: <-1.47, 2.39). Radiation risks of leukaemia were negative in early AECL workers and non-significantly increased in other workers. In analyses with separate terms for tritium and gamma doses, there was no evidence of increased risk from tritium exposure. All workers had mortality lower than the general population. CONCLUSION: Significantly increased risks for early AECL workers are most likely due to incomplete transfer of AECL dose records to the National Dose Registry. Analyses of the remainder of the Canadian nuclear workers (93.2%) provided no evidence of increased risk, but the risk estimate was compatible with estimates that form the basis of radiation protection standards. Study findings suggest that the revised Canadian cohort, with the exclusion of early AECL workers, would likely have an important effect on the 15-country pooled risk estimate of radiation-related risks of all cancer excluding leukaemia by substantially reducing the size of the point estimate and its significance.

Risk perception, trust, and factors related to a planned new nuclear power plant in Taiwan after the 2011 Fukushima disaster.

After the Fukushima nuclear disaster in March 2011, an international review of nuclear safety indicated that two of the three nuclear power plants (NPPs) operating in Taiwan were listed as the most dangerous in the world. To understand the perception of NPP risks by the public in Taiwan and their attitudes regarding a planned fourth NPP after the Fukushima nuclear incident in 2011, a study was conducted in August 2011. A sample of 2819 individuals responded to the survey, with 66% perceiving that Taiwan's safety management of NPPs was inferior to Japan's, while 40% perceived a higher possibility of nuclear accidents like that in Japan. On average, a 'safe' distance of 94 km from an NPP was expected. 56% opposed the planned fourth NPP, with females (adjusted odd ratios (aOR) 2.03; 95% confidence interval (CI) 1.71-2.41), residence near the planned fourth NPP (aOR/CI 13.90/7.79-24.80), distrust of safety management (aOR/CI 1.98/1.45-2.69) and emergency planning (aOR/CI 1.89/1.49-2.40) as the main determinants. Others included those who expected larger safe distances from an NPP (trend test, p < 0.001), perceived excess cancer risks of living within 30 km of an NPP (aOR/CI 2.74/2.02-3.71), and projection of no electric shortage without NPPs (aOR/CI 1.93/1.50-2.49). Given that Taiwan's large population lives close to the existing NPPs and long-term concerns about the safety of these nuclear plants, the Fukushima incident in Japan likely augmented public risk perceptions on nuclear power in general and on the planned fourth NPP.

Leukaemia in young children in the vicinity of British nuclear power plants: a case-control study.

BACKGROUND: Concern about the risk of leukaemia in children living near nuclear power plants (NPPs) persists. Previous British analyses have been area based and consequently thought to be less effective than case-control studies. METHODS: Cases of childhood leukaemia and non-Hodgkin lymphoma (LNHL) born and diagnosed in Great Britain between 1962 and 2007, with matched cancer-free controls, were analysed by logistic regression to estimate the risk of residential proximity at birth and diagnosis to the nearest NPP, adjusting for relevant variables. RESULTS: For 9821 children with LNHL under the age of 5 years, the estimated extra risk associated with residential proximity to an NPP at birth was negative-interpolated Odds Ratio (OR) at 5 km was 0.86 (0.49-1.52). The comparison of 10 618 children with LNHL under five with 16 760 similarly aged children with other cancers also gave a negative estimate of the extra risk of residential proximity at diagnosis-interpolated OR at 5 km was 0.86 (0.62-1.18). CONCLUSION: Our results show little evidence of an increase in risk of LNHL to children aged under 5 years from living in the vicinity of an NPP. Risk estimates are incompatible with comparable ones published in a recent German case-control study.