Occupational Exposure to Hydrazine and Subsequent Risk of Lung Cancer: 50-Year Follow-Up

Hydrazine is carcinogenic in animals, but there is inadequate evidence to determine if it is carcinogenic in humans. This study aimed to evaluate the association between hydrazine exposure and the risk of lung cancer.The cause specific mortality rates of a cohort of 427 men who were employed at an English factory that produced hydrazine between 1945 and 1971 were compared with national mortality rates.By the end of December 2012 205 deaths had occurred. For men in the highest exposure category with greater than two years exposure and after more than ten years since first exposure the relative risks compared with national rates were: 0.85 (95% CI: 0.18-2.48) for lung cancer, 0.61 (95% CI: 0.07-2.21) for cancers of the digestive system, and 0.44 (95% CI: 0.05-1.57) for other cancers.After 50 years of follow up, the results provide no evidence of an increased risk of death from lung cancer or death from any other cause

Analysis of mortality in a pooled cohort of Canadian and German uranium processing workers with no mining experience

International audiencePurpose Long-term health risks of occupational exposures to uranium processing were examined to better understand potential differences with uranium underground miners and nuclear reactor workers. Methods A cohort study of mortality of workers from Port Hope, Canada (1950–1999) and Wismut, Germany (1946–2008) employed in uranium milling, refining, and processing was conducted. Poisson regression was used to evaluate the association between cumulative exposures to radon decay products (RDP) and gamma-rays and causes of death potentially related to uranium processing. Results The pooled cohort included 7431 workers (270,201 person-years of follow-up). Mean RDP exposures were lower than in miners while gamma-ray doses were higher than in reactor workers. Both exposures were highly correlated (weighted rho = 0.81). Radiation risks of lung cancer and cardiovascular diseases (CVD) in males were increased but not statistically significant and compatible with risks estimated for miners and reactor workers, respectively. Higher RDP-associated CVD risks were observed for exposures 5–14 years prior to diagnosis compared to later exposures and among those employed <5 years. Radiation risks of solid cancers excluding lung cancer were increased, but not statistically significant, both for males and females, while all other causes of death were not associated with exposures. Conclusions In the largest study of uranium processing workers to systematically examine radiation risks of multiple outcomes from RDP exposures and gamma-rays, estimated radiation risks were compatible with risks reported for uranium miners and nuclear reactor workers. Continued follow-up and pooling with other cohorts of uranium processing workers are necessary for future comparisons with other workers of the nuclear fuel cycle. © 2017, The Author(s)

Effets de la contamination chronique à l'uranium sur la mortalité Bilan d'une étude-pilote chez les travailleurs de l'industrie nucléaire en France

National audienceBackground This article presents the mortality data compiled among a cohort of workers at risk of internal uranium exposure and discusses the extent to which this exposure might differentiate them from other nuclear workers. Methods The cohort consisted of 2897 Areva-NC-Pierrelatte plant workers, followed from 1st January 1968 through 31st December 2006 (79,892person-years). Mortality was compared with that of the French population, by calculating Standardized Mortality Ratios (SMR) and 95% confidence intervals (CI95%). External radiation exposure was reconstructed using external dosimetry archives. Internal uranium exposure was assessed using a plant-specific job-exposure-matrix, considering six types of uranium compounds according to their nature (natural and reprocessed uranium [RPU] and solubility [fast-F, moderate-M, and slow-S]). Exposure-effect analyses were performed for causes of death known to be related to external radiation exposure (all cancers and circulatory system diseases) and cancer of uranium target-organs (lung and hematopoietic and lymphatic tissues, HLT). Results A significant deficit of mortality from all causes (SMR=0.58; CI95% [0.53-0.63]), all cancers (SMR=0.72; CI95% [0.63-0.82]) and smoking related cancers was observed. Non-significant 30%-higher increase of mortality was observed for cancer of pleura (SMR=2.32; CI95% [0.75-5.41]), rectum and HLT, notably non-Hodgkin's lymphoma (SMR=1.38; CI95% [0.63-2.61]) and chronic lymphoid leukemia (SMR=2.36; CI95% [0.64-6.03]). No exposure-effect relationship was found with external radiation cumulative dose. A significant exposure-effect relationship was observed for slowly soluble uranium, particularly RPU, which was associated with an increase in mortality risk reaching 8 to 16% per unit of cumulative exposure score and 10 to 15% per year of exposure duration. Conclusion The Areva-NC-Pierrelatte workers cohort presents a non-significant over-mortality from HLT cancers, notably of lymphoid origin, unrelated to external radiation exposure. The pilot study suggests an association between mortality from the HLT and lung cancers and exposure to slowly soluble RPU compounds. The results of this study should be investigated further in more powerful studies, with a dose-response analysis based on individual assessment of uranium absorbed dose to uranium-target organs.Position du problème. Plusieurs études ont été réalisées chez les travailleurs du nucléaire français sur les effets de l’exposition externe aux rayonnements ionisants (RI). Une étude-pilote des effets de l’exposition interne à l’uranium sur la mortalité a été lancée en 2005. Les résultats de cette étude sont présentés et comparés à ceux des autres études des travailleurs du nucléaire. Méthodes: La cohorte de 2897 travailleurs de l’établissement Areva-NC-Pierrelatte a été suivie du 1er janvier 1968 jusqu’au 31 décembre 2006 (79 892 personnes-années). Sa mortalité est comparée à celle de la population française en calculant les SMR (« Standardized Mortality Ratio ») et les intervalles de confiance à 95 % (IC95 %). L’exposition externe aux RI est reconstituée via les archives dosimétriques. L’exposition à l’uranium est reconstituée via une matrice emplois-exposition. Six types d’uranium sont considérés selon leur isotopie (uranium naturel et uranium issu du retraitement, URT) et leur solubilité (forte-F, modérée-M et faible-S). L’analyse du lien entre les expositions et la mortalité porte sur les causes de décès associées aux RI (cancers et maladies du système circulatoire) et les cancers des organes-cibles de l’uranium inhalé (poumons et tissus lymphatique et hématopoïétique, TLH). Résultats: La cohorte présente une sous-mortalité toutes causes (SMR = 0,58 ; IC95 % [0,53–0,63]), tous cancers (SMR = 0,72 ; IC95 % [0,63–0,82]) et cancers associés au tabagisme traduisant l’effet du travailleur sain. Un excès non significatif est observé pour les cancers de la plèvre (SMR = 2,32 ; IC95 % [0,75–5,41]), du rectum et des TLH, notamment le lymphome non hodgkinien (SMR = 1,38 ; IC95 % [0,63–2,61]) et la leucémie lymphoïde chronique (SMR = 2,36 ; IC95 % [0,64–6,03]). Aucune relation significative avec la dose cumulée externe n’est mise en évidence. Pour l’uranium faiblement soluble, notamment l’URT, une augmentation de risque de mortalité de 8 à 16 % par point de score d’exposition cumulée et de 10 à 15 % par année d’exposition est observée. Conclusion: La cohorte Areva-NC-Pierrelatte présente une surmortalité (non significative) par cancers des TLH, notamment d’origine lymphoïde, sans lien avec l’exposition externe aux RI. L’étude-pilote suggère un lien entre la mortalité par cancer des TLH et des poumons et l’exposition à l’URT faiblement soluble. Ce résultat doit être confirmé par d’autres études, plus puissantes, et par des analyses dose-réponse reposant sur le calcul de la dose absorbée à l’organe-cible de l’uranium

Mortality (1968-2008) in a French cohort of uranium enrichment workers potentially exposed to rapidly soluble uranium compounds

International audienceObjectives Until recently, enrichment of uranium for civil and military purposes in France was carried out by gaseous diffusion using rapidly soluble uranium compounds. We analysed the relationship between exposure to soluble uranium compounds and exposure to external γ-radiation and mortality in a cohort of 4688 French uranium enrichment workers who were employed between 1964 and 2006. Methods Data on individual annual exposure to radiological and non-radiological hazards were collected for workers of the AREVA NC, CEA and Eurodif uranium enrichment plants from job-exposure matrixes and external dosimetry records, differentiating between natural, enriched and depleted uranium. Cause-specific mortality was compared with the French general population via standardised mortality ratios (SMR), and was analysed via Poisson regression using log-linear and linear excess relative risk models. Results Over the period of follow-up, 131 161 personyears at risk were accrued and 21% of the subjects had died. A strong healthy worker effect was observed all causes SMR=0.69, 95% CI 0.65 to 0.74. SMR for pleural cancer was significantly increased (2.3, 95% CI 1.06 to 4.4), but was only based on nine cases. Internal uranium and external γ-radiation exposures were not significantly associated with any cause of mortality. Conclusions This is the first study of French uranium enrichment workers. Although limited in statistical power, further follow-up of this cohort, estimation of internal uranium doses and pooling with similar cohorts should elucidate potential risks associated with exposure to soluble uranium compounds

Half-century archives of occupational medical data on French nuclear workers A dusty warehouse or gold mine for epidemiological research?

International audienceThis article discusses the availability and completeness of medical data on workers from the AREVA NC Pierrelatte nuclear plant and their possible use in epidemiological research on cardiovascular and metabolic disorders related to internal exposure to uranium. We created a computer database from files on 394 eligible workers included in an ongoing nested case-control study from a larger cohort of 2897 French nuclear workers. For each worker, we collected records of previous employment, job positions, job descriptions, medical visits, and blood test results from medical history. The dataset counts 9,471 medical examinations and 12,735 blood test results. For almost all of the parameters relevant for research on cardiovascular risk, data completeness and availability is over 90 %, but it varies with time and improves in the latest time period. In the absence of biobanks, collecting and computerising available good-quality occupational medicine archive data constitutes a valuable alternative for epidemiological and aetiological research in occupational health. Biobanks rarely contain biological samples over an entire worker's carrier and medical data from nuclear industry archives might make up for unavailable biomarkers that could provide information on cardiovascular and metabolic diseases © 2015 Institute

Circulatory disease in French nuclear fuel cycle workers chronically exposed to uranium: a nested case-control study.

There is growing evidence of an association between low-dose external γ-radiation and circulatory system diseases (CSDs), yet sparse data exist about an association with chronic internal uranium exposure and the role of non-radiation risk factors. We conducted a nested case-control study of French AREVA NC Pierrelatte nuclear workers employed between 1960 and 2005 to estimate CSD risks adjusting for major CSD risk factors (smoking, blood pressure, body mass index, total cholesterol and glycaemia) and external γ-radiation dose. The study included 102 cases of death from CSD and 416 controls individually matched on age, gender, birth cohort and socio-professional status. Information on CSD risk factors was collected from occupational medical records. Organ-specific absorbed doses were estimated using biomonitoring data, taking into account exposure regime and uranium physicochemical properties. External γ-radiation was measured by individual dosimeter badges. Analysis was conducted with conditional logistic regression. Workers were exposed to very low radiation doses (mean γ-radiation dose 2 and lung uranium dose 1 mGy). A positive but imprecise association was observed (excess OR per mGy 0.2, 95% CI 0.004 to 0.5). Results obtained after adjustment suggest that uranium exposure might be an independent CSD risk factor. Our results suggest that a positive association might exist between internal uranium exposure and CSD mortality, not confounded by CSD risk factors. Future work should focus on numerous uncertainties associated with internal uranium dose estimation and on understanding biological pathway of CSD after protracted low-dose internal radiation exposure

ICRP Publication 150: Cancer Risks from Plutonium and Uranium Exposure

International audienceThe objective of this publication is to provide a detailed review of results from recent epidemiological studies of cancer risk from exposure to plutonium and uranium, and how these results relate to the assumptions currently used for protection against alpha radiation. For plutonium, the two main studies are of the cohorts of workers employed at the nuclear installations at Mayak in the Russian Federation and at Sellafield in the United Kingdom. The analysis of the Mayak cohort provides an estimate of the slope of the dose-response for lung cancer risk, while at lower levels of plutonium exposure, the Sellafield cohort provides results that, within relatively large confidence intervals, are consistent with those for the Mayak cohort. Results from the Mayak cohort also show an association between plutonium exposure and risks of liver and bone cancers, but not of leukaemia. Lifetime excess risk of lung cancer mortality has been calculated for scenarios of acute and chronic inhalation of plutonium nitrate and plutonium oxide, similar to that done previously for radon and its decay products in Publication 115. Estimated lifetime excess risks of lung cancer mortality per unit absorbed dose are close to those derived from miner studies for exposure to radon and its progeny, and are compatible with the assumption of a radiation weighting factor of 20 for alpha particles. Epidemiological studies of cancer risk associated with uranium exposure have been conducted among cohorts of European and North American workers involved in the nuclear fuel cycle. Current results do not allow the reliable derivation of dose-risk models for uranium for any cancer type. Continuation of efforts to improve dose assessment associated with plutonium and uranium exposure is recommended for future researc