Risk of morbidity with stomach cancer among workers employed at radiation-hazardous enterprise

We performed retrospective research among a cohort made up of workers employed at "Mayak" Production Association (Mayak PA), a state nuclear enterprise, who had been exposed to long-term external gamma-irradiation and internal alpha-irradiation caused by plutonium-239 under inhalation introduction. Our research goal was to assess impacts exerted by occupa-tional irradiation and non-radiation factors on a risk of morbidity with stomach cancer (SC) in workers employed at Mayak PA. We used individual data on occupational irradiation doses obtained from "Dosimetric system for Mayak PA workers – 2008" for external gamma-irradiation, and "Dosimetric system for Mayak PA workers – 2013" for internal alpha-irradiation. We applied Poisson regression to calculated odds ratio (OR) for morbidity with stomach cancer among the examined cohort both for radiation and non-radiation factors. We detected statistically significant influence exerted on risk of morbidity with SC among workers employed at Mayak PA by the following factors: age, sex, attitudes towards to smoking and alcohol intake, stomach and duodenum ulcer, and external gamma-irradiation. Taking into account adjustments as per non-radiation factors, we detected a statistically significant increase in OR of morbidity with SC which was equal to 1.48 (95 % CI 1.10; 1.98), when a dose of external gamma-irradiation accumulated in the stomach walls was more than 1.0 Gy. We didn't detect any correlation between risk of morbidity with CS among the examined cohort and internal alpha-irradiation. Given that data obtained in epidemiologic research concerning impacts exerted by occupational irradiation on SC risks are ambiguous, it is necessary to clarify the obtained results and to perform more profound analysis of dose – response relationship among a more extended cohort of workers employed at Mayak PA

On the choice of methodology for evaluating dose-rate effects on radiation-related cancer risks.

Recently, several compilations of individual radiation epidemiology study results have aimed to obtain direct evidence on the magnitudes of dose-rate effects on radiation-related cancer risks. These compilations have relied on meta-analyses of ratios of risks from low dose-rate studies and matched risks from the solid cancer Excess Relative Risk models fitted to the acutely exposed Japanese A-bomb cohort. The purpose here is to demonstrate how choices of methodology for evaluating dose-rate effects on radiation-related cancer risks may influence the results reported for dose-rate effects. The current analysis is intended to address methodological issues and does not imply that the authors recommend a particular value for the dose and dose-rate effectiveness factor. A set of 22 results from one recent published study has been adopted here as a test set of data for applying the many different methods described here, that nearly all produced highly consistent results. Some recently voiced concerns, involving the recalling of the well-known theoretical point—the ratio of two normal random variables has a theoretically unbounded variance—that could potentially cause issues, are shown to be unfounded when aimed at the published work cited and examined in detail here. In the calculation of dose-rate effects for radiation protection purposes, it is recommended that meta-estimators should retain the full epidemiological and dosimetric matching information between the risks from the individual low dose-rate studies and the acutely exposed A-bomb cohort and that a regression approach can be considered as a useful alternative to current approaches

Cerebrovascular diseases in workers at Mayak PA: The difference in radiation risk between incidence and mortality.

A detailed analysis of cerebrovascular diseases (CeVD) for the cohort of workers at Mayak Production Association (PA) is presented. This cohort is especially suitable for the analysis of radiation induced circulatory diseases, due to the detailed medical surveillance and information on several risk factors. The risk after external, typically protracted, gamma exposure is analysed, accounting for potential additional internal alpha exposure. Three different endpoints have been investigated: incidence and mortality from all cerebrovascular diseases and incidence of stroke. Particular emphasis was given to the form of the dose-response relationship and the time dependence of the radiation induced risk. Young attained age was observed to be an important, aggravating modifier of radiation risk for incidence of CeVD and stroke. For incidence of CeVD, our analysis supports a dose response sub-linear for low doses. Finally, the excess relative risk per dose was confirmed to be significantly higher for incidence of CeVD compared to CeVD mortality and incidence of stroke. Arguments are presented for this difference to be based on a true biological effect

Ischemic heart disease in workers at Mayak PA: Latency of incidence risk after radiation exposure.

We present an updated analysis of incidence and mortality from atherosclerotic induced ischemic heart diseases in the cohort of workers at the Mayak Production Association (PA). This cohort constitutes one of the most important sources for the assessment of radiation risk. It is exceptional because it comprises information on several other risk factors. While most of the workers have been exposed to external gamma radiation, a large proportion has additionally been exposed to internal radiation from inhaled plutonium. Compared to a previous study by Azizova et al. 2012, the updated dosimetry system MWDS-2008 has been applied and methods of analysis have been revised. We extend the analysis of the significant incidence risk and observe that main detrimental effects of external radiation exposure occur after more than about 30 years. For mortality, significant risk was found in males with an excess relative risk per dose of 0.09 (95% CI: 0.02; 0.16) [Formula: see text] while risk was insignificant for females. With respect to internal radiation exposure no association to risk could be established

Dose-rate effects in radiation biology and radiation protection.

Quantification of biological effects (cancer, other diseases, and cell damage) associated with exposure to ionising radiation has been a major issue for the International Commission on Radiological Protection (ICRP) since its foundation in 1928. While there is a wealth of information on the effects on human health for whole-body doses above approximately 100 mGy, the effects associated with doses below 100 mGy are still being investigated and debated intensively. The current radiological protection approach, proposed by ICRP for workers and the public, is largely based on risks obtained from high-dose and high-dose-rate studies, such as the Japanese Life Span Study on atomic bomb survivors. The risk coefficients obtained from these studies can be reduced by the dose and dose-rate effectiveness factor (DDREF) to account for the assumed lower effectiveness of low-dose and low-dose-rate exposures. The 2007 ICRP Recommendations continue to propose a value of 2 for DDREF, while other international organisations suggest either application of different values or abandonment of the factor. This paper summarises the current status of discussions, and highlights issues that are relevant to reassessing the magnitude and application of DDREF

Stable intrachromosomal biomarkers of past exposure to densely ionizing radiation in several chromosomes of exposed individuals

10.1667/RR3231Radiation Research1623257-263RARE

What radiation dose does the FISH translocation assay measure in cases of incorporated radionuclides for the Southern Urals populations?

Toxicogenetic