Particle and metal exposure in Parisian subway: Relationship between exposure biomarkers in air, exhaled breath condensate, and urine.

Subway particulate toxicity results from in vitro and in vivo studies diverge and call for applied human research on outcomes from chronic exposures and potential exposure biomarkers. We aimed to (1) quantify airborne particulate matter (PM) concentrations (mass and number) and metal concentrations in exhaled breath condensate (EBC), urine, and PM; (2) investigate their associations (EBC vs. PM vs. urine); and (3) assess the relevance of EBC in biomonitoring. Nine subway workers in three jobs: station agents, locomotive operators and security guards were monitored during their 6-h shifts over two consecutive weeks. Six-hour weighed average mass concentrations expressed as PM10, PM2.5 and their metal concentrations were determined. Urine and EBC samples were collected pre- and post-shift. Ultrafine particle (UFP) number concentrations were quantified in PM and EBC samples. Metal concentrations in urine and EBC were standardized by creatinine and EBC volume, respectively, and log-transformed. Associations were investigated using Pearson correlation and linear mixed regression models, with participant's ID as random effect. PM concentrations were below occupational exposure limits (OEL) and varied significantly between jobs. Locomotive operators had the highest exposure (189 and 137 µg/m3 for PM10 and PM2.5, respectively), while station agents had the highest UFP exposure (1.97 × 104 particles/cm3). Five metals (Al, Fe, Zn, Cu, and Mn) in PM2.5 and three (Al, Fe, and Zn) in PM10 were above the limit of quantification (LOQ). Fe, Cu, Al and Zn were the most abundant by mass fraction in PM. In EBC, the metal concentrations in decreasing order were: Zn > Cu > Ni > Ba > Mn. Security guards had the highest EBC metal concentrations, and in particular Zn and Cu. Urinary metal concentrations in decreasing order were: Si > Zn > Mo > Ti > Cu > Ba ≈ Ni > Co. All urinary metal concentrations from the subway workers were similar to concentrations found in the general population. A statistically significant relationship was found for ultrafine particle number concentrations in PM and in EBC. Zn and Cu concentrations in post-shift EBC were associated with Zn and Cu concentrations in PM10 and with post-shift urinary Zn and Cu concentrations. Therefore, EBC appears a relevant matrix for assessing exposure to UFP in human biomonitoring when inhalation is a primary route of exposure. We found different temporal variation patterns between particle and metal exposures in three matrices (PM, urine, EBC) quantified daily over two full weeks in subway workers. These patterns might be related to metal oxidation, particulates' solubility and size as well as their lung absorption capabilities, which need to be further explored in toxicological research. Further research should also focus on understanding possible influences of low chronic exposures to subway particulates on health in larger cohorts.

Respiratory Disease Occupational Biomonitoring Collaborative Project (ROBoCoP): A longitudinal pilot study and implementation research in the Parisian transport company.

The ROBoCoP project is launched within the EU COST Action CA16113 "CliniMARK" aiming to increase the number of clinically validated biomarkers and focused on chronic obstructive pulmonary disease (COPD) biomarker development and validation. ROBoCoP encompasses two consecutive studies consisting of a pilot study followed by a field study. The pilot study is a longitudinal exposure assessment and biomarker study aiming at: 1-understanding the suitability of the candidate biomarkers in surveying populations at risk such as workers exposed to COPD causing agents; 2-determining the best sampling plan with respect to the half-life of the candidate biomarkers; 3-implementing and validating the sampling procedures and analytical methods; 4-selecting the best suitable biomarkers to be measured in the field. Each study participant is surveyed every day during the 6-8 h work-shifts for two consecutive weeks. The field study has an implementation research designe that enabled us to demonstrate the applicability of the standardized protocol for biomarker measurements in occupational settings while also assessing the biomarkers' validity. ROBoCoP will focus on particulate matter (PM) exposure measurements, exposure biomarkers and a series of effect biomarkers, including markers of lipoperoxidation: 8-isoprostane, malondialdehyd in exhaled breath condensate (EBC) and urine, potential markers of nitrosative stress: NO2-, NO3- and formate anion in EBC; markers of DNA oxidation: 8-hydroxy-2'deoxyguanosine in EBC and urine, marker of genotoxicity: micronuclei in buccal cells, and oxidative potential in exhaled air (OPEA). OPEA appears particularly promising as a clinical biomarker for detecting COPD, and will be tested independently and as part of a biomarker panel. COPD diagnosis will be performed by an experienced occupational physician according to international diagnostic standards and confirmed by a pulmonologist.This research will include approximatively 300 underground subway workers randomly selected from the personnel registry of a large Parisian transport company. Underground subways are suggested as the most PM polluted urban transport environment. We believe this occupational exposure is relevant for biomonitoring of workers and early detection of respiratory diseases.

Psychometric properties of burnout measures: a systematic review.

AIMS: Occupational Burnout (OB) is currently measured through several Patient-Reported Outcome Measures (PROMs) and some of them have become widely used in occupational health research and practice. We, therefore, aimed to review and grade the psychometric validity of the five OB PROMs considered as valid for OB measure in mental health professionals (the Maslach Burnout Inventory (MBI), the Pines' Burnout Measure (BM), the Psychologist Burnout Inventory (PBI), the OLdenburg Burnout Inventory (OLBI) and the Copenhagen Burnout Inventory (CBI)). METHODS: We conducted systematic literature searches in MEDLINE, PsycINFO and EMBASE databases. We reviewed studies published between January 1980 and September 2018 following a methodological framework, in which each step of PROM validation, the reference method, analytical technics and result interpretation criteria were assessed. Using the COnsensus-based Standards for the selection of health Measurement Instruments we evaluated the risk of bias in studies assessing content and criterion validity, structural validity, internal consistency, reliability, measurement error, hypotheses testing and responsiveness of each PROM. Finally, we assessed the level of evidence for the validity of each PROM using the GRADE approach. RESULTS: We identified 6541 studies, 19 of which were included for review. Fifteen studies dealt with MBI whereas BM, PBI, OLBI and CBI were each examined in only one study. OLBI had the most complete validation, followed by CBI, MBI, BM and PBI, respectively. When examining the result interpretation correctness, the strongest disagreement was observed for MBI (27% of results), BM (25%) and CBI (17%). There was no disagreement regarding PBI and OLBI. For OLBI and CBI, the quality of evidence for sufficient content validity, the crucial psychometric property, was moderate; for MBI, BM and PBI, it was very low. CONCLUSION: To be validly and reliably used in medical research and practice, PROM should exhibit robust psychometric properties. Among the five PROMs reviewed, CBI and, to a lesser extent, OLBI meet this prerequisite. The cross-cultural validity of these PROMs was beyond the scope of our work and should be addressed in the future. Moreover, the development of a diagnostic standard for OB would be helpful to assess the sensitivity and specificity of the PROMs and further reexamine their validity.The study protocol was registered in PROSPERO (CRD 42019124621).

Prevalence of somatic and psychiatric morbidity across occupations in Switzerland and its correlation with suicide mortality: results from the Swiss National Cohort (1990-2014).

BACKGROUND: Suicide is a major and complex public health problem. In Switzerland, suicide accounts for about 1000 deaths yearly and is the fourth leading cause of mortality. The first nationwide Swiss study of suicides identified eight male and four female occupations with statistically significant excess of suicide compared to the general Swiss population. Working time, self-employer status, low socio-economic status and low skill level required for occupation were associated with increase in suicide risk. Presently, we aim to compare the distribution of suicide risk across occupations with the prevalence of somatic and psychiatric morbidity in Swiss working-aged adults. We hypothesized that some diseases would cluster in particular occupations, indicating potential work-relatedness of suicides found in these occupations. METHODS: We used the Swiss National Cohort (SNC) and included 10575 males and 2756 females deceased by suicide between 1990 and 2014. We estimated the prevalence of 16 categories of concomitant diseases in each occupation, using national mortality records, and assessed the homogeneity of diseases distribution across occupations. For diseases, which prevalence varied significantly across occupations, we analyzed the correlation with the distribution of suicide risk, estimated as the standardized mortality ratio (SMR) of suicide. RESULTS: Mental and behavioral disorders were the most commonly reported concomitant diseases in our population. In men, the prevalence of these disorders and more specifically, the prevalence of substance-related and addictive disorders, and of psychotic disorders varied significantly across occupations and was correlated with the SMR of suicide. The prevalence of malignant neoplasms and the prevalence of diseases of the musculoskeletal system and connective tissue also varied significantly across male occupations, while in women, such a variation was observed for neoplasms of uncertain or unknown behavior and diseases of the nervous system and sense organs, without being correlated with the SMR of suicide. CONCLUSION: Some of the identified morbidities can be occupation-related and could negatively affect the working capacity and the employability, which in turn could be related to the suicide. Disentangling concomitant diseases according to their work-relatedness and relationship with the suicide risk is important for identifying occupation-related suicides, understanding their characteristics, and developing appropriated interventions for their prevention.

Urinary 8-isoprostane as a biomarker for oxidative stress. A systematic review and meta-analysis.

Oxidative stress is defined as an imbalance between the production and elimination of reactive oxygen species (ROS) are associated with various inflammation-related human disease. ROS can oxidize lipids, which subsequently undergo fragmentation to produce F2-isoprostanes (F2-IsoPs). Eight-isoprostane is one of the most extensively studied F2-IsoPs and the most commonly used biomarker for the assessment of oxidative stress in human studies. This urinary biomarker is quantified using either chemical or immunological techniques. A "physiological" range for 8-isoprostanes is needed to use this biomarker as a measure of excess oxidative stress originating from occupational exposures. However, ranges reported in the literature are inconsistent. We designed a standardized protocol of a systematic review and meta-analysis to assess baseline values for 8-isoprostane concentrations in urine of healthy adults and identify determinants of their inter- and intra-individual variability. We searched PubMed from journal inception and up to April 2019, and screened articles for studies containing F2-IsoPs concentrations in urine for healthy adult participants. We grouped studies in three biomarker groups: "8-isoprostane", "Isoprostanes" "15- F2t-Isoprostane". We computed geometric mean (GM) and geometric standard deviation (GSD) as the basis for the meta-analysis. Of the initial 1849 articles retrieved, 63 studies were included and 107 subgroups within these study populations were identified. We stratified the subgroups analyzed with the chemical methods by body mass index (BMI) reported. We provide pooled GM values for urinary 8-isoprostane concentrations in healthy adults, separately for chemical and immunological analysis in this review. The interquartile range (IQR) in subgroups with a mean BMI below 25 measured using chemical methods was 0.18 to 0.40 µg/g creatinine. We show that there is a significant positive association between BMI and urinary 8-isoprostane concentrations. We recommend adjusting urinary 8-isoprostane concentrations in spot urine with creatinine, quantifying 8-isoprostane with chemical analytical methods, and reporting results as median and quartiles. This will help in comparing results across studies.

Reference ranges of oxidative stress biomarkers selected for non-invasive biological surveillance of nanotechnology workers: Study protocol and meta-analysis results for 8-OHdG in exhaled breath condensate.

In the field of engineered nanomaterials (ENMs) and other airborne particulate exposure biomonitoring, circulating oxidative stress biomarkers appear promising. These biomarkers could be monitored in different biological matrices. Exhaled breath condensate (EBC) enables their measurements in the respiratory tract, without affecting airway function or creating inflammation. The 8-hydroxy-2-deoxyguanosine (8-OHdG) was found increased in the EBC of ENM-exposed workers. Our objectives were to assess the reference range of 8-OHdG in the EBC and to identify determinants of its inter- and intra-individual variability. The meta-analysis was stratified by analytical method (chemical versus immunochemical analysis) and resulted in a between-study variability over 99 % of the total variability. The between-study variability completely dominated the within-studies variability. By using a mixed model with study ID as a random effect rather than a meta-regression, only smoking was evidenced as a potential determinant of 8-OHdG inter-individual variability, and only when immunochemical analysis was used. To our knowledge, this is the first meta-analysis aimed at estimating reference values for 8-OHdG in the EBC. The estimated values should be considered preliminary, as they are based on a limited number of studies, mostly of moderate to low quality of evidence. Further research is necessary to standardize EBC sampling, storage and analytical methods. Such a standardization would enable a more accurate estimation of the reference ranges of the 8-OHdG and potentially other biomarkers measurable in the EBC, which are essential for a meaningful interpretation of the biomonitoring results.

State of knowledge on the occupational exposure to carbon nanotubes.

Carbon nanotubes (CNT) trigger fascination as well as anxiety, given their unique physical and chemical properties, and continuing concerns around their possible health effects. CNT exposure assessment is an integral component of occupational and environmental epidemiology, risk assessment, and management. We conducted a systematic review to analyze the quality of CNT occupational exposure assessments in field studies and to assess the relevance of available quantitative data from occupational hygiene and epidemiological perspectives. PubMed and Scopus databases were searched for the period 2000-2018. To grade the quality of each study, we used a standardized grid of seven criteria. The first criterion addressed 12 items deemed most relevant CNT physical-chemical properties with respect to their in vitro and in vivo toxicity. We included 27 studies from 11 countries in the review and graded them high (n = 2), moderate (n = 15) and low quality (n = 10). Half of the studies measured elemental carbon mass concentration (EC) using different methods and aerosol fractions. In 85% of studies, the observed values exceed the US National Institute for Occupational Safety and Health Recommended Exposure Limit. The quantification of CNT agglomerates and/or CNT contained fibers becomes increasingly common although lacking methodological standardization. Work activities with the greatest mean CNT mass concentrations were non-enclosed and included sieving, harvesting, packaging, reactor cleaning, extrusion and pelletizing. Some of the large studies defined standardized job titles according to exposure estimates at corresponding workstations and classified them by decreasing CNT exposure level: technicians > engineers > chemists. The already initiated harmonization of CNT exposure assessment and result reporting need to continue to favor not only studies in the field, but also to identify companies and workers using CNTs to characterize their exposures as well as monitor their health. This will enable an objective and realistic evaluation of risks associated with CNT applications and an appropriate risk management.

Healthy worker, healthy citizen: the place of occupational health within public health research in Switzerland.

OBJECTIVES: To assess the state of Swiss occupational health (OH) research over the period 2008-2017. METHODS: Two types of indicators were constructed, focused, respectively, on resources available for OH research and its output. Data for their assessment were gathered from specialized research institutions, professional associations, and the Swiss Federal Statistical Office. RESULTS: Thirty-two of 317 Ph.D./M.D.-Ph.D. theses delivered were in the field of OH. The number of OH physicians progressed substantially, but the density of OH professionals per number of active workers showed important variations between OH disciplines and geographical regions. The number of yearly peer-reviewed publications increased substantially but represented 6% of publications in public health in 2017. Psychological and respiratory health conditions were the most studied topics, while papers on cancers accounted for only 10%. CONCLUSIONS: This study suggests a limited place of OH research in the Swiss public health landscape and the need for a national research effort in OH. This requires an improved collaboration between regional and federal authorities and communication/coordination between public health authorities and OH executive institutions belonging to the economic sector.

Maternal admissions to intensive care units in France: Trends in rates, causes and severity from 2010 to 2014.

INTRODUCTION: Maternal intensive care unit admission is an indicator of severe maternal morbidity. The objective of this study was to estimate rates of maternal intensive care unit admission during or following pregnancy in France, and to describe the characteristics of women concerned, the severity of their condition, associated diagnoses, regional disparities, and temporal trends between 2010 and 2014. METHODS: Women hospitalised in France in intensive care units during pregnancy or up to 42 days after pregnancy between January 2010 and December 2014 were identified using the national hospital discharge database (PMSI-MCO). Trends in incidence rates were quantified using percentages of average annual variation based on a Poisson regression model. RESULTS: In total, 16,011 women were admitted to intensive care units, representing an overall incidence of 3.97‰ deliveries. This number decreased significantly by 1.7% on average per year. For women who gave birth (60.5% by C-section), 62.5% of admissions occurred during their hospitalisation for delivery. The SAPS II score, an indicator of severity, significantly increased from 18.4 in 2010 to 21.5 in 2014. Obstetrical haemorrhage (39.8%) and hypertensive complications during pregnancy (24.8%) were the most common reasons for admission. In mainland France, the Ile-de-France (i.e., greater Paris) region had the highest rates of intensive care units admission (5.05‰) while the Pays-de-la-Loire region had the lowest (2.69‰). CONCLUSION: The rate of maternal intensive care unit admission decreased from 2010 to 2014 in France, with a concomitant increase in case severity. In-depth studies are needed to understand the territorial disparities identified.

[Characteristics and health status of homeless women born in France and abroad: Results of Insee-Ined 2012 survey]. / Caractéristiques et état de santé des femmes sans-domicile nées en France et à l'étranger : résultats de l'enquête Insee­Ined 2012.

BACKGROUND: French national surveys among the homeless population in 2001 and 2012 provided a general description of the homeless beneficiaries of medical and social aids. However, given the increasing number of women in this population, mostly born abroad and accompanied by their children, a descriptive study of homeless women according to the fact of being born in France or abroad was conducted. METHODS: A probability sample of 1470 French-speaking homeless women was recruited for the Insee-Ined 2012 survey. Socio-demographic characteristics, life trajectories, work and employment over the last 12 months, perceived health, reported morbidity, use of care and medical coverage have been described, comparing homeless women born abroad with those born in France. RESULTS: Homeless women are young (median age=34 y.), often single (55%), without a partner (71%) and often accompanied by children (52%). The vast majority (60%) reported no salary during the previous 12 months. Housing conditions were less precarious in women born in France, but these women had a more difficult life history, a more unfavorable perception of their health status, and a higher frequency of chronic health problems. Homeless women born abroad seemed to have more precarious conditions of life and more difficulties to access aids and medical coverage. Overall, despite a relatively good availability of medical insurance, homeless women, regardless of the place of birth, often reported health problems, which were not treated. CONCLUSION: This study suggests that homeless women often have to deal with chronic health problems that are not treated. Homeless women born abroad are characterized by more precarious living conditions that women born in France. Although younger, with an overall favorable perception of their health and declaring less often an addiction, their general state of health appears to be as fragile as for women born in France. Actions towards homeless women should be implemented to promote their access to care.

[Maternal deaths related to social vulnerabilities. Results from the French confidential enquiry into maternal deaths, 2010-2012]. / Mortalité maternelle chez les femmes en situation de précarité. Résultats de l'ENCMM, France 2010­2012.

The theme of deprivation is new for the ENCMM. In view of the perceived increase in the number of maternal deaths that may be related to a deprivation situation, we sought to understand the main dimensions that could contribute to maternal death in this context, in order to propose a definition. The selection of cases made a posteriori is mainly based on a qualitative judgment. Between 2010 and 2012, among the deaths evaluated by the CNEMM, one or more elements related to social vulnerability were identified in 8.6% of the cases (18 deaths). The direct criteria used were the concepts of "deprivation" or "social difficulties", difficulties of housing, language barriers and isolation. The absence of prenatal care was retained as an indirect marker. We excluded cases where psychiatric pathology and/or addiction were predominant. Of the 18 cases identified with deprivation factors, death was considered "unavoidable" in 2 cases (11%), "certainly avoidable" or "possibly avoidable" in 13 cases (72%). In 3 cases (17%), avoidability could not be determined. Avoidability was related to the content and adequacy of care in 11 cases out of 13 (85%) and the patient's interaction with the health care system in 10 of 18 cases (56%). The analysis of maternal deaths among women in precarious situations points out that the link between socio-economic deprivation and poor maternal health outcomes potentially includes a specific risk of maternal death.

[Effects of chronic uranium internal exposure on mortality: results of a pilot study among French nuclear workers]. / 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.

BACKGROUND: 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 (79,892 person-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.

Uranium carcinogenicity in humans might depend on the physical and chemical nature of uranium and its isotopic composition: results from pilot epidemiological study of French nuclear workers.

OBJECTIVE: To study the cancer risk related to protracted, low-dose exposure to different industrial uranium compounds, paying attention to their isotopic composition and solubility. METHODS: Two thousand and ninety-seven workers employed at the AREVA NC uranium processing plant (France) were followed up for mortality from 1960 to 2006. Historical exposure to uranium and other carcinogenic chemical and physical pollutants was assessed on the basis of the plant-specific job-exposure matrix. For each type of uranium, Cox regression models stratified on sex and calendar period, and adjusted for socioeconomic status and potentially confounding co-exposures were used to estimate hazard ratios (HRs) for mortality from lung cancer (53 deaths) and lymphatic and hematopoietic tissue malignancies (21 deaths). RESULTS: We observed that exposure to reprocessed uranium entails increasing risks of mortality from lung cancer and lymphatic and hematopoietic malignancies (the most significant HR being respectively 1.14 (95% CI: 1.00-1.31) and 1.20 (95% CI: 1.01-1.43) per unit of a time-lagged log-transformed continuous exposure scores), and that the HRs tend to increase with decreasing solubility of the compounds. CONCLUSION: Our results suggest that uranium carcinogenicity may depend on isotopic composition and solubility of uranium compounds. This study is the first to show the carcinogenic effect of slowly soluble reprocessed uranium on two uranium target organs. This finding is consistent with data from epidemiological and experimental studies on similar compounds but need to be confirmed in the more powerful dose-response analysis.

Malignant pleural mesothelioma risk among nuclear workers: a review.

Exposure to ionising radiation has been suggested as a causal risk factor for malignant pleural mesothelioma (MPM). Studies of patients treated by radiotherapy for primary cancers have suggested that radiation contributes to the development of secondary MPM. Here we examined the risk to nuclear workers of MPM related to exposure to low doses of occupational radiation at low dose rates. All results concerning MPM risk in published studies of nuclear workers were examined for their association with radiation exposure and potential confounders. We found 19 relevant studies. Elevated risks of pleural cancer were reported in most (15/17) of these studies. Eight reported risks higher for radiation monitored workers than for other workers. However, of 12 studies that looked at associations with ionising radiation, only one reported a significant dose-risk association. Asbestos was an important confounder in most studies. We conclude that studies of nuclear workers have not detected an association between ionising radiation exposure and MPM. Further investigations should improve the consideration of asbestos exposure at the same time as they address the risk of MPM related to occupational exposure of nuclear workers to low doses of ionising radiation at low dose rates.

Characterisation of protracted low-level exposure to uranium in the workplace: A comparison of two approaches.

Retrospective estimates of internal doses received by workers in the nuclear industry following intake of radionuclides, based on bioassay data, are a benchmark method in epidemiological studies. Nonetheless, full information relative to thousands of people included in an epidemiological cohort is rarely available, thus implying difficulties to estimate exposure precisely. To evaluate the cumulative exposure to uranium in a cohort of the AREVA NC Pierrelatte plant workers, we compared the epidemiological Job Exposure Matrix (JEM) method with the dosimetric method based on biological monitoring of exposure for 30 workers randomly selected within the cohort. A moderate to strong correlation was observed between the estimators resulting from the two approaches, thereby validating the JEM as a tool that can be used to characterise cumulative exposure to uranium in the cohort. In addition, this study showed that the JEM is a valuable complement to the interpretation of bioassy, (1) in providing information on exposure periods as well as on physical and chemical form of the radionuclides and (2) in compensating for the lack of exposure data regarding the very earliest periods. Combining the two methods may improve the precision in reconstructing cumulative exposure for epidemiological studies.

[Development of a job exposure matrix for the epidemiological follow-up of workers in the French nuclear industry]. / Construction d'une matrice emplois--expositions pour le suivi épidémiologique des travailleurs de l'industrie nucléaire en France. Résultats d'une étude pilote.

BACKGROUND: A pilot study was carried out in the AREVA NC Pierrelatte nuclear facility in order to investigate a possible carcinogenic effect of internal radiation exposure among nuclear workers in France. The objective of this study was to develop a method for retrospective reconstruction of the occupational exposure to internal radiation from uranium and associated chemical exposures. METHODS: A plant- and period-specific job exposure matrix (JEM) was designed. Job groups and exposure agents groups including uranium compounds and other chemical agents known as being carcinogenic, mutagenic or toxic were defined by an expert committee. Exposure was evaluated by active and retired workers included in the evaluator committee. A quantitative assignment of quantity and frequency of handling (both coded from 0 to 3) was performed for each agent groups using a method derived from the Delphi technique. RESULTS: In all, 23 experts and 353 evaluators participated to the JEM elaboration. A final JEM involved 232 "job-periods" presenting throughout the plant period 1960-2006 and 22 exposure agents groups in use at the plant. Six of them involved uranium compounds classified by their blood-transferability and toxicity characteristics. A first validation of the JEM by experts in radiological protection and industrial hygiene showed an acceptable internal consistency. CONCLUSION: In the context of missing past exposure measurement data, the plant- and period-specific job exposure matrices may be considered as a valid alternative for exposure estimation. This method may be applied to other nuclear plants and offers allowance to investigate a possible carcinogenic effect of internal radiation exposure among nuclear workers.