A major update to the International Nuclear Workers Study was undertaken that allows us to report updated estimates of associations between radiation and site-specific solid cancer mortality. A cohort of 309 932 nuclear workers employed in France, the United Kingdom, and the United States were monitored for external radiation exposure. Associations of radiation with cancer mortality were quantified as the excess relative rate (ERR) per gray (Gy) using a maximum likelihood and a Markov chain Monte Carlo method (to stabilize estimates via a hierarchical regression). The analysis included 28 089 deaths due to solid cancer, the most common being lung, prostate, and colon cancer. Using maximum likelihood, positive estimates of ERR per Gy were obtained for stomach, colon, rectum, pancreas, peritoneum, larynx, lung, pleura/mesothelioma, bone and connective tissue, skin, prostate, testis, bladder, kidney, thyroid, and residual cancers. Negative estimates of ERR per Gy were found cancers of oral cavity and pharynx, esophagus, and ovary. A hierarchical model stabilized site-specific estimates of association, including for lung (ERR per Gy = 0.65; 95% credible interval [CrI], 0.24-1.07), prostate (ERR per Gy = 0.44; 95% CrI, -0.06 to 0.91), and colon cancer (ERR per Gy = 0.53; 95% CrI, -0.07 to 1.11). The results contribute evidence regarding associations between low-dose radiation and cancer.

OBJECTIVES:Understanding of long-term lung cancer risks from radon decay products (RDP) exposure derives largely from studies of uranium miners. We aimed to compare mortality for lung and other cancers to the general population, to estimate excess absolute rate (EAR) and excess relative rate (ERR) from RDP exposure, and to estimate the joint effects of RDP and cigarette smoking in extended follow-up of a cohort of 4137 male uranium miners from the US Colorado Plateau. METHODS:We extended mortality follow-up through 2016 and re-evaluated RDP exposure against original work history and mine records. We calculated standardised mortality ratios (SMRs) compared with a regional population, evaluated EAR of lung cancer mortality using standardised rate ratios and modelled ERR using Cox proportional hazards regression. We evaluated interactions of RDP with smoking pack-years, attained age (AA) and time-since-exposure (TSE). RESULTS:There were 695 lung cancer deaths, including 146 among never-smokers and light smokers. The overall SMR was >4; the EAR per unit RDP exposure increased substantially with smoking pack-years and decades of follow-up. Lung cancer ERR decreased with AA and TSE. ERR attenuation at high exposure rates was smaller than observed elsewhere. Joint effects of RDP and smoking were submultiplicative but greater-than-additive, appearing closer to multiplicative at lower RDP exposures. Pancreas was the only other site showing a significantly positive ERR per unit exposure. CONCLUSIONS:Excess rates of lung cancer mortality persist throughout the lifespan among this cohort of uranium miners. Information about RDP-smoking interactions is of interest for occupational and general population exposure.

Structural firefighters are exposed to an array of polycyclic aromatic hydrocarbons (PAHs) as a result of incomplete combustion of both synthetic and natural materials. PAHs are found in both the particulate and vapor phases in the firefighting environment and are significantly associated with acute and chronic diseases, including cancer. Using a fireground exposure simulator (FES) and standing mannequins dressed in four different firefighter personal protective equipment (PPE) conditions, each with varying levels of protective hood interface and particulate-blocking features, the efficacy of the hoods was assessed against the ingress of PAHs (specifically, naphthalene). The authors also explored the effectiveness of a 100% cotton turtleneck at further attenuating the amount of naphthalene reaching the surface of the mannequin's neck. Air samples were collected at the breathing zone, abdomen, and thigh heights from the 6 ft-2 in mannequins used in this study. Naphthalene was the most abundant PAH (55% of the total PAH concentrations) in the FES and existed primarily in the vapor phase (92% vapor in the breathing zone). Additionally, bulk base layer and under the base layer polytetrafluoroethylene (PTFE) filter samples (used as skin surrogates) were collected from the neck region of the mannequins and analyzed for PAHs. A larger percentage of naphthalene was collected on the filter under the traditional knit hoods than on the cotton base layer, suggesting a small protective effect of the base layer against solid-phase naphthalene. Previous studies investigating naphthalene by employing air sampling under PPE have found a larger protective effect of base layers against the ingress of naphthalene vapor. PAHs that exist primarily as particulate in the fire environment were largely not detected on the base layers or PTFE filters under the gear. Further research is needed that involves more sensitive methods and non-static human subjects.

Radon is a known cause of lung cancer. Protective standards for radon exposure are derived largely from studies of working populations that are prone to healthy worker survivor bias. This bias can lead to underprotection of workers and is a key barrier to understanding health effects of many exposures. We apply inverse probability weighting to study a set of hypothetical exposure limits among 4137 male, White and American Indian radon-exposed uranium miners in the Colorado Plateau followed from 1950 to 2005. We estimate cumulative risk of lung cancer through age 90 under hypothetical occupational limits. We estimate that earlier implementation of the current US Mining Safety and Health Administration annual standard of 4 working level months (implemented here as a monthly exposure limit) could have reduced lung cancer mortality from 16 of 100 workers to 6 of 100 workers (95% confidence interval, 3/100, 8/100), in contrast with previous estimates of 10 of 100 workers. Our estimate is similar to that among contemporaneous occupational cohorts. Inverse probability weighting is a simple and computationally efficient way address healthy worker survivor bias to contrast health effects of exposure limits and estimate the number of excess health outcomes under exposure limits at work.

BACKGROUND:Ethylene oxide (EtO) is a recognized carcinogen of concern in occupational and environmental settings, but evidence of cancer risks in humans remains limited. Since new EtO emission standards and mitigation measures have been proposed, further investigation of EtO cancer risks is needed to inform quantitative risk assessment. OBJECTIVE:Our objective was to estimate the association between cumulative EtO exposure and risk of death from breast cancer. METHODS:We had data on 7,549 women from the largest cohort of EtO-exposed workers who were employed for at least 1 y at one of 13 US facilities, with mortality follow-up from 1 January 1960 to 31 December 2021. We estimated relative rates (RR) of the association between cumulative EtO exposure [parts per million days (ppm-days)] and breast cancer mortality using Cox proportional hazard models, using a matched risk-set sampling design with attained age as the underlying time scale. We further examined a subcohort of women who participated in interviews that contained information about breast cancer risk factors. RESULTS:Cumulative exposure to EtO was associated with elevated RRs of breast cancer mortality (181 deaths). In a log-log model with a 20-y lag fit, workers who accrued 3,650 ppm-days of exposure (equivalent to 10 y exposed at a rate of 1 ppm) had over three times the rate of breast cancer death in comparison with unexposed workers (RR at 3,650 ppm-days=3.15; 95% CI: 1.78, 5.60). This RR remained elevated for the subset of the cohort with interview data after matching on potential confounders (RR at 3,650 ppm-days=3.22; 95% CI: 1.52, 7.13). We observed evidence of variation in RRs by time since exposure and exposure rate. DISCUSSION:This updated analysis of an EtO-exposed worker cohort builds on evidence that EtO is a human breast carcinogen and supports recent exposure reduction proposals. Given the high prevalence of breast cancer, the large number of workers exposed to EtO and the potential for widespread environmental exposure increased risks observed even in the low exposure range are of serious public health importance. https://doi.org/10.1289/EHP15566.

Background We aimed to develop a method for assessing occupational styrene exposures for application in epidemiological studies on risks of lymphohematopoietic neoplasms and other malignant and non-malignant diseases in the European and the US glass reinforced plastics industries. Method We estimated a linear mixed effects model based on individual airborne personal measurements of styrene from the glass reinforced plastics industry in Denmark, Norway, Sweden, UK, and the US. The most suitable model was chosen based on its predictive power as assessed using cross validation with different combinations of predictors; and by comparing their prediction errors. Results We created a database containing 21,201 personal and area measurements but a subset of 14,440 personal measurements that spanned a period from 1962 to 2018, were used in the analysis. The selected model included fixed effects for year, sampling duration, measurement reason, product, process and random effects for country and worker. There was strong agreement between the model's predictions and actual exposure values indicating a good fit (Lin's CCC: 0.85 95% CI 0.84, 0.85). There were regional differences in exposure levels, with the UK and the US having comparable exposures that were higher than those in the Nordic countries. Higher exposures were consistent with measurements collected for inspection purposes, the lamination process, and specific products. Styrene exposure levels have decreased annually on average by 7%. Conclusion Our exposure model and the resulting exposure predictions will enable estimation of lifetime occupational exposure for individual workers in the European and the US glass reinforced plastics industry and possibly related health risks among employees. The approach facilitates understanding of the uncertainty in our prediction model and can inform analysis of the bias that application of our exposure assessment approach can produce in epidemiologic analyses of exposure-response associations. Addressing systematic sources of bias can increase confidence in the conclusions of the epidemiologic analysis.

Background In studies of occupational health, longitudinal environmental exposure, and biomonitoring data are often subject to right skewing and left censoring, in which measurements fall below the limit of detection (LOD). To address right-skewed data, it is common practice to log-transform the data and model the geometric mean, assuming a log-normal distribution. However, if the transformed data do not follow a known distribution, modeling the mean of exposure may result in bias and reduce efficiency. In addition, when examining longitudinal data, it is possible that certain covariates may vary over time.Objective To develop predictive quantile regression models to resolve the issues of left censoring and time-dependent covariates and to quantitatively evaluate if previous and current covariates can predict current and/or future exposure levels.Methods To address these gaps, we suggested incorporating different substitution approaches into quantile regression and utilizing a method for selecting a working type of time dependency for covariates.Results In a simulation study, we demonstrated that, under different types of time-dependent covariates, the approach of multiple random value imputation outperformed the other approaches. We also applied our methods to a carbon nanotube and nanofiber exposure study. The dependent variables are the left-censored mass of elemental carbon at both the respirable and inhalable aerosol size fractions. In this study, we identified some potential time-dependent covariates with respect to worker-level determinants and job tasks.Conclusion Time dependency for covariates is rarely accounted for when analyzing longitudinal environmental exposure and biomonitoring data with values less than the LOD through predictive modeling. Mistreating the time-dependency as time-independency will lead to an efficiency loss of regression parameter estimation. Therefore, we addressed time-varying covariates in longitudinal exposure and biomonitoring data with left-censored measurements and illustrated an entire conditional distribution through different quantiles.

The International Nuclear Workers Study (INWORKS) contributes knowledge on the dose-response association between predominantly low dose, low dose rate occupational exposures to penetrating forms of ionizing radiation and cause-specific mortality. By extending follow-up of 309,932 radiation workers from France (1968–2014), the United Kingdom (1955–2012), and the United States (1944–2016) we increased support for analyses of temporal variation in radiation-cancer mortality associations. Here, we examine whether age at exposure, time since exposure, or attained age separately modify associations between radiation and mortality from all solid cancers, solid cancers excluding lung cancer, lung cancer, and lymphohematopoietic cancers. Multivariable Poisson regression was used to fit general relative rate models that describe modification of the linear excess relative rate per unit organ absorbed dose. Given indication of greater risk per unit dose for solid cancer mortality among workers hired in more recent calendar years, sensitivity analyses considering the impact of year of hire on results were performed. Findings were reasonably compatible with those from previous pooled and country-specific analyses within INWORKS showing temporal patterns of effect measure modification that varied among cancers, with evidence of persistent radiation-associated excess cancer risk decades after exposure, although statistically significant temporal modification of the radiation effect was not observed. Analyses stratified by hire period (< 1958, 1958+) showed temporal patterns that varied; however, these analyses did not suggest that this was due to differences in distribution of these effect measure modifiers by hire year.

Structural firefighters are exposed to a complex set of contaminants and combustion byproducts, including volatile organic compounds (VOCs). Additionally, recent studies have found structural firefighters' skin may be exposed to multiple chemical compounds via permeation or penetration of chemical byproducts through or around personal protective equipment (PPE). This mannequin-based study evaluated the effectiveness of four different PPE conditions with varying contamination control measures (incorporating PPE interface design features and particulate blocking materials) to protect against ingress of several VOCs in a smoke exposure chamber. We also investigated the effectiveness of long-sleeve base layer clothing to provide additional protection against skin contamination. Outside gear air concentrations were measured from within the smoke exposure chamber at the breathing zone, abdomen, and thigh heights. Personal air concentrations were collected from mannequins under PPE at the same general heights and under the base layer at abdomen and thigh heights. Sampled contaminants included benzene, toluene, styrene, and naphthalene. Results suggest that VOCs can readily penetrate the ensembles. Workplace protection factors (WPFs) were near one for benzene and toluene and increased with increasing molecular weight of the contaminants. WPFs were generally lower under hoods and jackets compared to under pants. For all PPE conditions, the pants appeared to provide the greatest overall protection against ingress of VOCs, but this may be due in part to the lower air concentrations toward the floor (and cuffs of pants) relative to the thigh-height outside gear concentrations used in calculating the WPFs. Providing added interface control measures and adding particulate-blocking materials appeared to provide a protective benefit against less-volatile chemicals, like naphthalene and styrene.

Background Environmental exposure and biomonitoring data with repeated measurements from environmental and occupational studies are commonly right-skewed and in the presence of limits of detection (LOD). However, existing model has not been discussed for small-sample properties and highly skewed data with non-detects and repeated measurements. Objective Marginal modeling provides an alternative to analyzing longitudinal and cluster data, in which the parameter interpretations are with respect to marginal or population-averaged means. Methods We outlined the theories of three marginal models, i.e., generalized estimating equations (GEE), quadratic inference functions (QIF), and generalized method of moments (GMM). With these approaches, we proposed to incorporate the fill-in methods, including single and multiple value imputation techniques, such that any measurements less than the limit of detection are assigned values. Results We demonstrated that the GEE method works well in terms of estimating the regression parameters in small sample sizes, while the QIF and GMM outperform in large-sample settings, as parameter estimates are consistent and have relatively smaller mean squared error. No specific fill-in method can be deemed superior as each has its own merits. Impact Marginal modeling is firstly employed to analyze repeated measures data with non-detects, in which only the mean structure needs to be correctly provided to obtain consistent parameter estimates. After replacing non-detects through substitution methods and utilizing small-sample bias corrections, in a simulation study we found that the estimating approaches used in the marginal models have corresponding advantages under a wide range of sample sizes. We also applied the models to longitudinal and cluster working examples.

Background A major update to the International Nuclear Workers Study (INWORKS) was undertaken to strengthen understanding of associations between low-dose exposure to penetrating forms of ionising radiation and mortality. Here, we report on associations between radiation dose and mortality due to haematological malignancies. Methods We assembled a cohort of 309 932 radiation-monitored workers (269 487 [87%] males and 40 445 [13%] females) employed for at least 1 year by a nuclear facility in France (60 697 workers), the UK (147 872 workers), and the USA (101363 workers). Workers were individually monitored for external radiation exposure and followed-up from Jan 1, 1944, to Dec 31, 2016, accruing 1072 million person-years of follow-up. Radiation-mortality associations were quantified in terms of the excess relative rate (ERR) per Gy of radiation dose to red bone marrow for leukaemia excluding chronic lymphocytic leukaemia (CLL), as well as subtypes ofleukaemia, myelodysplastic syndromes, non-Hodgkin and Hodgkin lymphomas, and multiple myeloma. Estimates of association were obtained using Poisson regression methods. Findings The association between cumulative dose to red bone marrow, lagged 2 years, and leukaemia (excluding CLL) mortality was well described by a linear model (ERR per Gy 268, 90% CI 113 to 455, n=771) and was not modified by neutron exposure, internal contamination monitoring status, or period of hire. Positive associations were also observed for chronic myeloid leukaemia (957, 400 to 1791, n=122) and myelodysplastic syndromes alone (319, 035 to 733, n=163) or combined with acute myeloid leukaemia (155, 005 to 342, n=598). No significant association was observed for acute lymphoblastic leukaemia (425, -419 to 1932, n=49) or CLL (020, -181 to 221, n=242). A positive association was observed between radiation dose and multiple myeloma (162, 006 to 364, n=527) whereas minimal evidence of association was observed between radiation dose and non-Hodgkin lymphoma (027, -061 to 139, n=1146) or Hodgkin lymphoma (060, -364 to 483, n=122) mortality. Interpretation This study reports a positive association between protracted low dose exposure to ionising radiation and mortality due to some haematological malignancies. Given the relatively low doses typically accrued by workers in this study (16 mGy average cumulative red bone marrow dose) the radiation attributable absolute risk of leukaemia mortality in this population is low (one excess death in 10 000 workers over a 35-year period). These results can inform radiation protection standards and will provide input for discussions on the radiation protection system. Funding National Cancer Institute, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Institut de Radioprotection et de S & ucirc;ret & eacute; Nucl & eacute;aire, Orano, Electricit & eacute; de France, UK Health Security Agency. Copyright (c) 2024. World Health Organization. Published by Elsevier Ltd/Inc/BV. All rights reserved.

The Pooled Uranium Miners Analysis (PUMA) study is the largest uranium miners cohort with 119,709 miners, 4.3 million person-years at risk and 7754 lung cancer deaths. Excess relative rate (ERR) estimates for lung cancer mortality per unit of cumulative exposure to radon progeny in working level months (WLM) based on the PUMA study have been reported. The ERR/WLM was modified by attained age, time since exposure or age at exposure, and exposure rate. This pattern was found for the full PUMA cohort and the 1960 + sub-cohort, i.e., miners hired in 1960 or later with chronic low radon exposures and exposure rates. The aim of the present paper is to calculate the lifetime excess absolute risk (LEAR) of lung cancer mortality per WLM using the PUMA risk models, as well as risk models derived in previously published smaller uranium miner studies, some of which are included in PUMA. The same methods were applied for all risk models, i.e., relative risk projection up to <95 years of age, an exposure scenario of 2 WLM per year from age 18–64 years, and baseline mortality rates representing a mixed Euro-American-Asian population. Depending upon the choice of model, the estimated LEAR per WLM are 5.38 × 10 − 4 or 5.57 × 10 − 4 in the full PUMA cohort and 7.50 × 10 − 4 or 7.66 × 10 − 4 in the PUMA 1960 + sub-cohort, respectively. The LEAR per WLM estimates derived from risk models reported for previously published uranium miners studies range from 2.5 × 10 − 4 to 9.2 × 10 − 4 . PUMA strengthens knowledge on the radon-related lung cancer LEAR, a useful way to translate models for policy purposes.

Introduction Studies of nuclear workers provide insights into the health effects of ionizing radiation at levels relevant to contemporary workers and the general public. We evaluated the association between penetrating ionizing radiation exposure and cancer mortality subtypes in a large pooled cohort of US nuclear workers. Follow-up was extended an additional decade to improve power and examine cancers with longer latency. Materials and Methods The pooled cohort includes 101,363 workers from five US Department of Energy and Department of Defense nuclear facilities, followed for causes of death between 1944 and 2016. Workers were individually monitored for ionizing radiation exposure with the use of personal dosimeter badges. The association between cumulative external penetrating ionizing radiation exposure and cancer subtypes were modeled as the excess relative rate per Sievert (ERR Sv-1) using Cox regression. Results There were 13,568 cancer deaths during follow-up. We observed positive associations between ionizing radiation exposure and all solid cancer mortality (ERR Sv-1=0.19; 95%CI: -0.10, 0.52), and all lymphatic and hematopoietic cancers (ERR Sv-1=2.10; 95%CI: 0.97, 3.48). These associations were stronger among a contemporary sub cohort of workers first hired 1960 or later for both solid cancer (ERR Sv-1= 2.23; 95% CI: 1.13, 3.49) and all lymphatic and hematopoietic cancers (ERR Sv-1= 6.26; 95%CI: 2.86, 10.83). Additionally, we observed positive associations for several site specific lymphatic and hematopoietic cancer types, as well as lung cancer. In some instances, we observed modification by time since exposure and age at exposure. Conclusions This analysis confirms the association between low dose, low dose-rate radiation and leukemias, and strengthens the evidence base supporting the radiogenic nature of some solid cancers. The extended follow-up, individual dosimetry, and precise estimates provided by this large pooled analysis can better inform current radiological protection models.

Introduction The US Radiation Exposure Compensation Act (RECA) provides compensation to some workers whose health was affected by uranium industry employment. Originally scheduled to terminate in 2022, the US government recently extended RECA benefits for two more years. Another RECA amendment proposes to extend the deadline further, defines additional compensable diseases, and expands eligibility to more contemporary uranium miners. Materials and Methods Researchers at NIOSH conduct extended follow-up on the cohort of US Colorado Plateau uranium miners, and participate in the international Pooled Uranium Miners Analysis (PUMA). Here we apply our recent research findings from both studies to contextualize the health burdens faced by surviving uranium miners, and examine how our research findings relate to the proposed extension and expansion of RECA. Results Former US uranium miners die of silicosis (Standardized Mortality Ratio (SMR)=41.4; 95%CI:30.9–54.3), pneumoconiosis (SMR=39.6; 95%CI:29.3–52.3), idiopathic pulmonary fibrosis (SMR=4.8; 95%CI:3.7–6.1), and lung cancer (SMR=4.5; 95%CI:4.2–4.9) at higher rates than expected. These mortality excesses continue to be observed in recent calendar years. In the PUMA study, uranium miners had higher rates of lung, liver, larynx, stomach, and pleural cancers than expected, and miners hired in later periods also had higher rates of lung and stomach cancer than expected. A positive association between radon exposure and lung cancer mortality is seen in the full PUMA cohort as well as in the sub-cohort of more contemporary miners. Conclusions Recent analyses suggest there be more US uranium miners who develop compensable diseases after the planned termination of RECA benefits in 2024. Uranium miners die at elevated rates from several cancer types that are not currently compensable. Contemporary uranium miners who are ineligible for compensation due to their employment dates experience many of the same health hazards as early-period miners. The proposed amendments to RECA are generally consistent with recent scientific results.

Background: This study examined age-group differences in the rate, severity, and cost of injuries among construction workers to support evidence-based worker safety and health interventions in the construction industry. Methods: Ohio workers' compensation claims for construction workers were used to estimate claim rates and costs by age group. We analyzed claims data auto-coded into five event/exposure categories: transportation incidents; slips, trips, and falls (STFs); exposure to harmful substances and environments; contact with objects and equipment (COB); overexertion and bodily reaction. American Community Survey data were used to determine the percentage of workers in each age group. Results: From 2007-2017, among 72,416 accepted injury claims for w166,000 construction full-time equivalent (FTE) per year, nearly half were caused by COB, followed by STFs (20%) and overexertion (20%). Claim rates related to COB and exposure to harmful substances and environments were highest among those 18-24 years old, with claim rates of 313.5 and 25.9 per 10,000 FTE, respectively. STFs increased with age, with the highest claim rates for those 55-64 years old (94.2 claims per 10,000 FTE). Overexertion claim rates increased and then declined with age, with the highest claim rate for those 35 -44 years old (87.3 per 10,000 FTE). While younger workers had higher injury rates, older workers had higher proportions of lost-time claims and higher costs per claim. The total cost per FTE was highest for those 45-54 years old ($1,122 per FTE). Conclusion: The variation in rates of injury types by age suggests that age-specific prevention strategies may be useful. (c) 2023 The Authors. Published by Elsevier B.V. on behalf of Occupational Safety and Health Research Institute, Korea Occupational Safety and Health Agency. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Introduction Ionizing radiation is an established carcinogen. Previously, the International Nuclear Workers Study (INWORKS), a pooled cohort of 308,297 workers from the United States (US), the United Kingdom (UK), and France followed 1944–2005, yielded an estimated excess relative rate of 0.51 per Gy (90% CI = 0.23, 0.82) for cancer mortality (19,748 deaths). Prior analyses suggested potential for healthy worker survivor bias and modification by age-at-exposure and time-since-exposure. Material and Methods We reanalyzed INWORKS data using the parametric g-formula, which can address healthy worker survivor bias. We estimated impacts of 2 hypothetical interventions: 1) reduce historical standards of worker equivalent doses to 5 mSv/year; and, 2) exposure to constant levels of 20 mGy/year vs. 5 mGy/year while at work. This approach requires models for exposure, employment and cause-specific mortality. Mortality models allow variation in the radiation-mortality association with age-at-exposure and time-since-exposure. Results Conditional on prior exposure and covariates, employment in the prior year was inversely associated with mortality among French workers but positively associated in US and UK workers. Associations between dose and cancer mortality were largest for doses received after age 45, lagged 30+ years. Approximately 224 cancer deaths per 1,000 workers were expected by age 90 in the pooled cohort. Relative to historical exposure levels (10% of working-years > 5 mGy/year), we estimated that a hypothetical standard at 5 mGy/year would result in 6.9 (95% CI = -5.7, 19) fewer cancer deaths per 1,000 workers by age 90. A constant exposure at 5 mGy/year (relative to 20 mGy/year) would have resulted in 13 (95% CI = -1.1, 27) fewer deaths. Conclusion Our results suggest that confounding by employment status was present, suggesting healthy worker survivor bias. The importance of doses at older ages and long times-since-exposure suggest continued need to assess potential impacts of occupational ionizing radiation exposures.

Objective To evaluate the effect of protracted low dose, low dose rate exposure to ionising radiation on the risk of cancer. Design Multinational cohort study. Setting Cohorts of workers in the nuclear industry in France, the UK, and the US included in a major update to the International Nuclear Workers Study (INWORKS). Participants 309 932 workers with individual monitoring data for external exposure to ionising radiation and a total follow-up of 10.7 million person years. Main outcome measures Estimates of excess relative rate per gray (Gy) of radiation dose for mortality from cancer. Results The study included 103 553 deaths, of which 28 089 were due to solid cancers. The estimated rate of mortality due to solid cancer increased with cumulative dose by 52% (90% confidence interval 27% to 77%) per Gy, lagged by 10 years. Restricting the analysis to the low cumulative dose range (0-100 mGy) approximately doubled the estimate of association (and increased the width of its confidence interval), as did restricting the analysis to workers hired in the more recent years of operations when estimates of occupational external penetrating radiation dose were recorded more accurately. Exclusion of deaths from lung cancer and pleural cancer had a modest effect on the estimated magnitude of association, providing indirect evidence that the association was not substantially confounded by smoking or occupational exposure to asbestos. Conclusions This major update to INWORKS provides a direct estimate of the association between protracted low dose exposure to ionising radiation and solid cancer mortality based on some of the world’s most informative cohorts of radiation workers. The summary estimate of excess relative rate solid cancer mortality per Gy is larger than estimates currently informing radiation protection, and some evidence suggests a steeper slope for the dose-response association in the low dose range than over the full dose range. These results can help to strengthen radiation protection, especially for low dose exposures that are of primary interest in contemporary medical, occupational, and environmental settings.

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.