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.

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 year at one of 13 US facilities, with mortality follow-up from January 1, 1960, to December 31, 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 which 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-year lag fit, workers who accrued 3,650 ppm-days of exposure (equivalent to 10 years exposed at a rate of 1 ppm) had over three times the rate of breast cancer death compared to 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 upon 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.

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.

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.

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: The risk of solid cancers from low-level protracted ionizing radiation is not well characterized. Nuclear workers provide valuable information on the effects of ionizing radiation in contemporary exposure scenarios relevant to workers and the public. METHODS: We evaluated the association between penetrating ionizing radiation exposure and solid cancer mortality among a pooled cohort of nuclear workers in the USA, with extended follow-up to examine cancers with long latencies. This analysis includes 101 363 workers from five nuclear facilities, with 12 069 solid cancer deaths between 1944 and 2016. The association between cumulative equivalent dose measured in sieverts (Sv) and solid cancer subtypes were modelled as the excess relative rate per Sv (ERR Sv-1) using Cox regression. RESULTS: For the association between ionizing radiation exposure and all solid cancer mortality we observed an elevated rate (ERR Sv-1=0.19; 95% CI: -0.10, 0.52), which was higher among a contemporary sub-cohort of workers first hired in 1960 or later (ERR Sv-1= 2.23; 95% CI: 1.13, 3.49). Similarly, we observed an elevated rate for lung cancer mortality (ERR Sv-1= 0.65; 95% CI: 0.09, 1.30) that was higher among contemporary hires (ERR Sv-1= 2.90; 95% CI: 1.00, 5.26). CONCLUSIONS: Although concerns remain about confounding, measurement error and precision, this analysis strengthens the evidence base indicating there are radiogenic risks for several solid cancer types.

OBJECTIVES: Radon is a ubiquitous occupational and environmental lung carcinogen. We aim to quantify the association between radon progeny and lung cancer mortality in the largest and most up-to-date pooled study of uranium miners. METHODS: The pooled uranium miners analysis combines 7 cohorts of male uranium miners with 7754 lung cancer deaths and 4.3 million person-years of follow-up. Vital status and lung cancer deaths were ascertained between 1946 and 2014. The association between cumulative radon exposure in working level months (WLM) and lung cancer was modelled as the excess relative rate (ERR) per 100 WLM using Poisson regression; variation in the association by temporal and exposure factors was examined. We also examined analyses restricted to miners first hired before 1960 and with <100 WLM cumulative exposure. RESULTS: In a model that allows for variation by attained age, time since exposure and annual exposure rate, the ERR/100 WLM was 4.68 (95% CI 2.88 to 6.96) among miners who were less than 55 years of age and were exposed in the prior 5 to <15 years at annual exposure rates of <0.5 WL. This association decreased with older attained age, longer time since exposure and higher annual exposure rate. In analyses restricted to men first hired before 1960, we observed similar patterns of association but a slightly lower estimate of the ERR/100 WLM. CONCLUSIONS: This new large, pooled study confirms and supports a linear exposure-response relationship between cumulative radon exposure and lung cancer mortality which is jointly modified by temporal and exposure factors.

For over 50 years, the National Institute for Occupational Safety and Health (NIOSH) has aided epidemiologists in the analysis of occupational cohort studies with the Life Table Analysis System (LTAS).1 LTAS simplifies person-year analyses, which is a central feature of occupational epidemiology research. LTAS is regularly used in occupational epidemiology studies to calculate standardised mortality ratios (SMRs). SMRs continue to be used in occupational epidemiology to compare the mortality experience of a cohort to a national or regional population. While there are limitations to SMRs, such as the inability to evaluate a dose–response association and bias towards the null from the healthy worker effect, SMRs remain an important tool in characterising the overall occupational experience of workers across different industries. SMRs are also an important surveillance tool in occupational and environmental settings. Many occupational cohort studies have used the NIOSH-LTAS system to conduct seminal research, such as a study of first responders to the World Trade Center disaster2 and a study of neurodegenerative diseases among National Football League (NFL) players,3 among many others.

BACKGROUND: Despite reductions in exposure for workers and the general public, radon remains a leading cause of lung cancer. Prior studies of underground miners depended heavily upon information on deaths among miners employed in the early years of mine operations when exposures were high and tended to be poorly estimated. OBJECTIVES: To strengthen the basis for radiation protection, we report on the follow-up of workers employed in the later periods of mine operations for whom we have more accurate exposure information and for whom exposures tended to be accrued at intensities that are more comparable to contemporary settings. METHODS: We conducted a pooled analysis of cohort studies of lung cancer mortality among 57,873 male uranium miners in Canada, Czech Republic, France, Germany, and the United States, who were first employed in 1960 or later (thereby excluding miners employed during the periods of highest exposure and focusing on miners who tend to have higher quality assessments of radon progeny exposures). We derived estimates of excess relative rate per 100 working level months (ERR/100 WLM) for mortality from lung cancer. RESULTS: The analysis included 1.9 million person-years of observation and 1,217 deaths due to lung cancer. The relative rate of lung cancer increased in a linear fashion with cumulative exposure to radon progeny (ERR/100 WLM = 1.33; 95% CI: 0.89, 1.88). The association was modified by attained age, age at exposure, and annual exposure rate; for attained ages  < 55  y, the ERR/100 WLM was 8.38 (95% CI: 3.30, 18.99) among miners who were exposed at  ≥ 35  years of age and at annual exposure rates of  < 0.5 working levels. This association decreased with older attained ages, younger ages at exposure, and higher exposure rates. DISCUSSION: Estimates of association between radon progeny exposure and lung cancer mortality among relatively contemporary miners are coherent with estimates used to inform current protection guidelines. https://doi.org/10.1289/EHP10669.

The US Radiation Exposure Compensation Act (RECA) is a government compensation programme, which provides partial restitution to individuals whose health was affected by nuclear weapons testing or uranium industry employment. RECA covers US uranium miners employed between 1942 and 1971 who developed or died from lung cancer, pulmonary fibrosis, silicosis, pneumoconiosis or cor pulmonale related to lung fibrosis. RECA is set to terminate this year. The filing deadline for living claimants or spouses of deceased claimants is 10 July 2022.1 To assess evidence of whether uranium miners will continue to develop compensable diseases after the termination of RECA, we examined mortality rate trends within the US Colorado Plateau uranium miner cohort.

OBJECTIVE: This study evaluated the impact of a state workers' compensation (WC) insurer's onsite risk control (RC) services on insured employers' WC claim frequency and cost. METHODS: We used two methods to model 2004-2017 claims data from 4,606 employers that received RC visits over time and compare this claims experience to matching employers that did not receive RC services. RESULTS: Relative total WC claim rates increased slightly after RC services, while relative lost-time claims rates either remained similar or decreased and WC cost rates decreased. The impact of RC services on reducing WC costs was cumulative up to the fourth visit but diminished thereafter. CONCLUSIONS: The insurer RC consultation program was effective in reducing WC cost rates for serviced employers. This is consistent with other research conducted on insurer RC services and related regulatory visits.

Introduction: This study analyzed workers compensation (WC) claims among private employers insured by the Ohio state-based WC carrier to identify high-risk industries by detailed cause of injury. Methods: A machine learning algorithm was used to code each claim by U.S. Bureau of Labor Statistics (BLS) event/exposure. The codes assigned to lost-time (LT) claims with lower algorithm probabilities of accurate classification or those LT claims with high costs were manually reviewed. WC data were linked with the state's unemployment insurance (UI) data to identify the employer's industry and number of employees. BLS data on hours worked per employee were used to estimate full-time equivalents (FTE) and calculate rates of WC claims per 100 FTE. Results: 140,780 LT claims and 633,373 medical-only claims were analyzed. Although counts and rates of LT WC claims declined from 2007 to 2017, the shares of leading LT injury event/exposures remained largely unchanged. LT claims due to Overexertion and Bodily Reaction (33.0%) were most common, followed by Falls, Slips, and Trips (31.4%), Contact with Objects and Equipment (22.5%), Transportation Incidents (7.0%), Exposure to Harmful Substances or Environments (2.8%), Violence and Other Injuries by Persons or Animals (2.5%), and Fires and Explosions (0.4%). These findings are consistent with other reported data. The proportions of injury event/exposures varied by industry, and high-risk industries were identified. Conclusions: Injuries have been reduced, but prevention challenges remain in certain industries. Available evidence on intervention effectiveness was summarized and mapped to the analysis results to demonstrate how the results can guide prevention efforts. Practical Applications: Employers, safety/health practitioners, researchers, WC insurers, and bureaus can use these data and machine learning methods to understand industry differences in the level and mix of risks, as well as industry trends, and to tailor safety, health, and disability prevention services and research. 2021

BACKGROUND: Exposure data with repeated measures from occupational studies are frequently right-skewed and left-censored. To address right-skewed data, data are generally log-transformed and analyses modeling the geometric mean operate under the assumption the data are log-normally distributed. However, modeling the mean of exposure may lead to bias and loss of efficiency if the transformed data do not follow a known distribution. In addition, left censoring occurs when measurements are below the limit of detection (LOD). OBJECTIVE: To present a complete illustration of the entire conditional distribution of an exposure outcome by examining different quantiles, rather than modeling the mean. METHODS: We propose an approach combining the quantile regression model, which does not require any specified error distributions, with the substitution method for skewed data with repeated measurements and non-detects. RESULTS: In a simulation study and application example, we demonstrate that this method performs well, particularly for highly right-skewed data, as parameter estimates are consistent and have smaller mean squared error relative to existing approaches. SIGNIFICANCE: The proposed approach provides an alternative insight into the conditional distribution of an exposure outcome for repeated measures models.

PURPOSE: Risks of occupational radiation exposures of workers involved in uranium refining and processing ("uranium processing workers") may be different from risks of other workers from the nuclear fuel cycle. Pooling of individual-level data from published studies and analysis using similar dosimetry and statistical methods might provide valuable insights into risks from occupational uranium and external ionizing radiation exposures. METHODS: We pooled the data for workers from four uranium processing facilities (Fernald Feed Materials Production Center, Ohio; Mallinckrodt Chemical Works Uranium Division, Missouri; Middlesex Sampling Plant, New Jersey; and the Port Hope Radium and Uranium Refining and Processing Plant, Canada). Employment began as early as the 1930s in Canada and follow-up for vital status was as late as 2017. These facilities used similar methods to process Belgian Congo pitchblende ore which contained high concentrations of uranium, radium, and their decay products. In addition, workers were exposed to elevated levels of gamma radiation, fission product contaminants in recycled uranium and ambient radon decay products. Non-radiation exposures of industrial hygiene concern were silica dust inhalation, heavy metal toxicity from uranium, solvents, acid mists and chemicals associated with uranium processing. Exposure and outcome data were harmonized using similar definitions and dose reconstruction methods. Standardized mortality ratios (SMR) were estimated by comparing mortality in the pooled cohort with age-, sex- and calendar time-specific general population mortality rates for the U.S. and Canada. RESULTS: Over 12,400 workers will be evaluated for cancer and non-cancer mortality in relation to exposures to uranium byproducts and gamma radiation (including ∼1,300 females). In total, death from 560 lung cancers, 503 nonmalignant respiratory diseases, 67 renal diseases, 1,596 ischemic heart diseases, and 101 dementia and Alzheimer's diseases (AD) were detected among male workers during follow-up. Mean cumulative doses were 45 millisievert for whole-body external exposures and 172 milligray for lung dose from radon decay products. Of the 16 pooled SMRs, seven were above 1.00, none were significantly low, and only one was significantly high, i.e., dementia and AD among males (SMR =1.29; 95% confidence interval: 1.04,1.54). CONCLUSIONS: This is the largest study to date to examine health risks in uranium processing workers (excluding uranium enrichment workers). The pooling of uranium processing worker data will address issues of importance today, specifically the concerns for cleanup workers and environmental contamination from the operation of past and present nuclear reactor and radiation facilities, reactor accidents, and possible terrorist events.

The evidence of styrene as a human lung carcinogen has been inconclusive. Occupational cohorts within the reinforced plastics industry are an ideal population to study this association due to relatively high levels of exposure to styrene and lack of concomitant exposures to other known carcinogens. However, healthy worker survivor bias (HWSB), where healthier workers stay employed longer and thus have higher exposure potential, is a likely source of confounding bias for exposure-response associations, in part due to styrene's acute effects. We studied a cohort of 5163 boatbuilders exposed to styrene in Washington state employed between 1959 and 1978; prior regression analyses demonstrated little evidence for an exposure-response between styrene exposure and lung cancer mortality. Based on estimates of necessary components of HWSB, we found evidence for a potentially large HWSB. Using g-estimation of a structural nested model to account for HWSB we estimated that one year of exposure >30 ppm accelerates time to lung cancer death by 2.3 years (95% Confidence intervals=1.53, 2.94). Our results suggest possibly strong HWSB in our small cohort and indicate that large, influential studies of styrene exposed workers may suffer similar biases, warranting a re-assessment of the evidence of long-term health effects of styrene exposure.

As the Fire Service becomes more aware of the potential health effects from occupational exposure to hazardous contaminants, personal protective equipment (PPE) manufacturers, and fire departments have responded by developing and implementing improved means of firefighter protection, including more frequent laundering of PPE after exposures. While laboratory testing of new PPE designs and the effect of laundering on PPE fabric provides a useful way to evaluate these approaches, laboratory scale testing does not necessarily translate to full garment protection. Utilizing a fireground smoke exposure simulator, along with air and/or filter-substrate sampling for polycyclic aromatic hydrocarbons (PAHs) and benzene, this pilot study tested the chemical-protective capabilities of firefighting PPE of different designs (knit hood vs. particulate-blocking hood, turnout jacket with zipper closure vs. hook & dee closure), including the impact of repeatedly exposing and cleaning (through laundering or decontamination on-scene) PPE 40 times. Overall, PAH contamination on filters under hoods in the neck region were higher (median PAHs = 14.7 µg) than samples taken under jackets in the chest region (median PAHs = 7.05 µg). PAH levels measured under particulate-blocking hoods were lower than levels found under knit hoods. Similarly, zippered closures were found to provide a greater reduction in PAHs compared to hook & dee closures. However, neither design element completely eliminated contaminant ingress. Measurements for benzene under turnout jackets were similar to ambient chamber air concentrations, indicating little to no attenuation from the PPE. The effect of laundering or on-scene decontamination on contaminant breakthrough appeared to depend on the type of contaminant. Benzene breakthrough was negatively associated with laundering, while PAH breakthrough was positively associated. More research is needed to identify PPE features that reduce breakthrough, how targeted changes impact exposures, and how fireground exposures relate to biological absorption of contaminants.

OBJECTIVE: Linear and non-linear dose-response relationships between radiation absorbed dose to the lung from internally deposited uranium and external sources and circulatory system disease (CSD) mortality were examined in a cohort of 23 731 male and 5552 female US uranium enrichment workers. METHODS: Rate ratios (RRs) for categories of lung dose and linear excess relative rates (ERRs) per unit lung dose were estimated to evaluate the associations between lung absorbed dose and death from ischaemic heart disease (IHD) and cerebrovascular disease. RESULTS: There was a suggestion of modestly increased IHD risk in workers with internal uranium lung dose above 1 milligray (mGy) (RR=1.4, 95% CI 0.76 to 2.3) and a statistically significantly increased IHD risk with external dose exceeding 150 mGy (RR=1.3, 95% CI 1.1 to 1.6) compared with the lowest exposed groups. ERRs per milligray were positive for IHD and uranium internal dose and for both outcomes per gray external dose, although the CIs generally included the null. CONCLUSIONS: Non-linear dose-response models using restricted cubic splines revealed sublinear responses at lower internal doses, suggesting that linear models that are common in radioepidemiological cancer studies may poorly describe the association between uranium internal dose and CSD mortality.

This study evaluated the effectiveness of ergonomic interventions in material handling operations involving 33 employers and 535 employees from 2012 to 2017. Outcomes included employee-reported low back/upper extremity pain and safety incidents at baseline, every three months, and annually for up to two years. A total of 32.5% of employees completed at least one survey, while 13.6% completed all nine surveys over two years. Among highly exposed employees (who reported handling >= 50 lbs. > 33% of the time), upper extremity pain frequency and severity were lower among those who reported using the intervention routinely versus those that reported using their body strength alone to handle objects >= 50 lbs. After excluding from analyses one employer that used anti-fatigue mats, low back pain frequency was also significantly lower among highly exposed intervention users. In conclusion, there was some evidence that the interventions were effective in reducing employee-reported pain for highly exposed employees.

OBJECTIVES: To improve exposure estimates and reexamine exposure-response relationships between cumulative styrene exposure and cancer mortality in a previously studied cohort of US boatbuilders exposed between 1959 and 1978 and followed through 2016. METHODS: Cumulative styrene exposure was estimated from work assignments and air-sampling data. Exposure-response relationships between styrene and select cancers were examined in Cox proportional hazards models matched on attained age, sex, race, birth cohort and employment duration. Models adjusted for socioeconomic status (SES). Exposures were lagged 10 years or by a period maximising the likelihood. HRs included 95% profile-likelihood CIs. Actuarial methods were used to estimate the styrene exposure corresponding to 10(-4) extra lifetime risk. RESULTS: The cohort (n= 5163) contributed 201 951 person-years. Exposures were right-skewed, with mean and median of 31 and 5.7 ppm-years, respectively. Positive, monotonic exposure-response associations were evident for leukaemia (HR at 50 ppm-years styrene = 1.46; 95% CI 1.04 to 1.97) and bladder cancer (HR at 50 ppm-years styrene =1.64; 95% CI 1.14 to 2.33). There was no evidence of confounding by SES. A working lifetime exposure to 0.05 ppm styrene corresponded to one extra leukaemia death per 10 000 workers. CONCLUSIONS: The study contributes evidence of exposure-response associations between cumulative styrene exposure and cancer. Simple risk projections at current exposure levels indicate a need for formal risk assessment. Future recommendations on worker protection would benefit from additional research clarifying cancer risks from styrene exposure.

OBJECTIVES: To update the mortality experience of a previously studied cohort of 29 992 US urban career firefighters compared with the US general population and examine exposure-response relationships within the cohort. METHODS: Vital status was updated through 2016 adding 7 years of follow-up. Cohort mortality compared with the US population was evaluated via life table analyses. Full risk-sets, matched on attained age, race, birthdate and fire department were created and analysed using the Cox proportional hazards regression to examine exposure-response associations between select mortality outcomes and exposure surrogates (exposed-days, fire-runs and fire-hours). Models were adjusted for a potential bias from healthy worker survivor effects by including a categorical variable for employment duration. RESULTS: Compared with the US population, mortality from all cancers, mesothelioma, non-Hodgkin's lymphoma (NHL) and cancers of the oesophagus, intestine, rectum, lung and kidney were modestly elevated. Positive exposure-response relationships were observed for deaths from lung cancer, leukaemia and chronic obstructive pulmonary disease (COPD). CONCLUSIONS: This update confirms previous findings of excess mortality from all cancers and several site-specific cancers as well as positive exposure-response relations for lung cancer and leukaemia. New findings include excess NHL mortality compared with the general population and a positive exposure-response relationship for COPD. However, there was no evidence of an association between any quantitative exposure measure and NHL.

BACKGROUND: Mortality tends to be higher among people who do not work than among workers, but the impact of work-related disability on mortality has not been well studied. METHODS: The vital status through 2015 was ascertained for 14 219 workers with an accepted workers' compensation claim in West Virginia for a low back injury in 1998 or 1999. Mortality among the cohort compared with the West Virginia general population was assessed using standard life table techniques. Associations of mortality and disability-related factors within the cohort were evaluated using Cox proportional hazards regression. RESULTS: Compared to the general population, mortality from accidental poisoning was significantly elevated among the overall cohort and lost-time claimants. Most deaths from accidental poisoning in the cohort were due to drug overdoses involving opioids. Mortality from intentional self-harm was also significantly elevated among lost-time claimants. In internal analyses, overall mortality and mortality from cancer, heart disease, intentional self-harm, and drug overdoses involving opioids was significantly associated with lost time. Overall mortality and mortality from drug overdoses involving opioids were also significantly associated with amount of lost time, permanent partial disability, and percent permanent disability. Heart disease mortality was also significantly associated with the amount of lost time. CONCLUSIONS: The results suggest that disability itself may impact mortality risks. If confirmed, these results reinforce the importance of return to work and other efforts to reduce disability.

BACKGROUND: A small but increasing number of studies have examined the risk of injury among temporary workers compared to that among workers in permanent employer arrangements. The purpose of this study was to conduct a comparative analysis of injury risk among temporary and permanent employer workers using a large dataset of workers' compensation (WC) claims of injury. METHODS: Over 1.3 million accepted WC claims in Ohio during the years 2001 to 2013 were analyzed, including 45 046 claims from workers employed by temporary services agencies. General descriptive statistics, injury rates and rate ratios (temporary to permanent workers) were calculated by injury type and event, industry group, and industry manual classes. RESULTS: Injured temporary workers were younger and had less tenure compared to injured permanent workers. Temporary workers had higher injury rates, and lower lost-time and medical costs. Differences in injury rates between temporary and permanent workers varied by injury event, industry, and manual class. CONCLUSION: Temporary workers had higher overall injury rates than permanent workers, controlling for industry manual class. These differences were pronounced for certain industries and injury events. We were not able to control for age and tenure of the worker, so it is not clear how these factors affected observed results. These findings were mostly similar to those from other studies using WC data from the states of Washington and Illinois. Together, these studies provide insights to improve injury prevention among temporary workers, however, additional research is still needed to improve safety and health programming for this group of workers.

BACKGROUND: Ambulance service workers frequently transfer and transport patients. These tasks involve occupational injury risks such as heavy lifting, awkward postures, and frequent motor vehicle travel. METHODS: We examined Ohio workers' compensation injury claims among state-insured ambulance service workers working for private employers from 2001 to 2011. Injury claim counts and rates are presented by claim types, diagnoses, and injury events; only counts are available by worker characteristics. RESULTS: We analyzed a total of 5882 claims. The majority were medical-only (<8 days away from work). The overall injury claim rate for medical-only and lost-time cases was 12.1 per 100 full-time equivalents. Sprains and strains accounted for 60% of all injury claims. Overexertion from patient handling was the leading injury event, followed by motor vehicle roadway incidents. CONCLUSIONS: Study results can guide the development or improvement of injury prevention strategies. Focused efforts related to patient handling and vehicle incidents are needed.

BACKGROUND: Chromosome translocations are a biomarker of cumulative exposure to ionizing radiation. We examined the relation between the frequency of translocations and cosmic radiation dose in 83 male airline pilots. METHODS: Translocations were scored using fluorescence in situ hybridization chromosome painting. Cumulative radiation doses were estimated from individual flight records. Excess rate and log-linear Poisson regression models were evaluated. RESULTS: Pilots' estimated median cumulative absorbed dose was 15 mGy (range 4.5-38). No association was observed between translocation frequency and absorbed dose from all types of flying [rate ratio (RR) = 1.01 at 1 mGy, 95% confidence interval (CI) 0.97-1.04]. However, additional analyses of pilots' dose from only commercial flying suggested an association (RR = 1.04 at 1 mGy, 95% CI 0.97-1.13). DISCUSSION: Although this is the largest cytogenetic study of male commercial airline pilots to date of which the authors are aware, future studies will need additional highly exposed pilots to better assess the translocation-cosmic radiation relation.

BACKGROUND: Commercial use of carbon nanotubes and nanofibers (CNT/F) in composites and electronics is increasing; however, little is known about health effects among workers. We conducted a cross-sectional study among 108 workers at 12 U.S. CNT/F facilities. We evaluated chest symptoms or respiratory allergies since starting work with CNT/F, lung function, resting blood pressure (BP), resting heart rate (RHR), and complete blood count (CBC) components. METHODS: We conducted multi-day, full-shift sampling to measure background-corrected elemental carbon (EC) and CNT/F structure count concentrations, and collected induced sputum to measure CNT/F in the respiratory tract. We measured (nonspecific) fine and ultrafine particulate matter mass and count concentrations. Concurrently, we conducted physical examinations, BP measurement, and spirometry, and collected whole blood. We evaluated associations between exposures and health measures, adjusting for confounders related to lifestyle and other occupational exposures. RESULTS: CNT/F air concentrations were generally low, while 18% of participants had evidence of CNT/F in sputum. Respiratory allergy development was positively associated with inhalable EC (p=0.040) and number of years worked with CNT/F (p=0.008). No exposures were associated with spirometry-based metrics or pulmonary symptoms, nor were CNT/F-specific metrics related to BP or most CBC components. Systolic BP was positively associated with fine particulate matter (p-values: 0.015-0.054). RHR was positively associated with EC, at both the respirable (p=0.0074) and inhalable (p=0.0026) size fractions. Hematocrit was positively associated with the log of CNT/F structure counts (p=0.043). CONCLUSIONS: Most health measures were not associated with CNT/F. The positive associations between CNT/F exposure and respiratory allergies, RHR, and hematocrit counts may not be causal and require examination in other studies.

OBJECTIVE: To examine dose-response relationships between internal uranium exposures and select outcomes among a cohort of uranium enrichment workers. METHODS: Cox regression was conducted to examine associations between selected health outcomes and cumulative internal uranium with consideration for external ionizing radiation, work-related medical X-rays and contaminant radionuclides technetium ((99) Tc) and plutonium ((239) Pu) as potential confounders. RESULTS: Elevated and monotonically increasing mortality risks were observed for kidney cancer, chronic renal diseases, and multiple myeloma, and the association with internal uranium absorbed organ dose was statistically significant for multiple myeloma. Adjustment for potential confounders had minimal impact on the risk estimates. CONCLUSION: Kidney cancer, chronic renal disease, and multiple myeloma mortality risks were elevated with increasing internal uranium absorbed organ dose. The findings add to evidence of an association between internal exposure to uranium and cancer. Future investigation includes a study of cancer incidence in this cohort.

BACKGROUND: Carbon nanotubes and nanofibers (CNT/F) are increasingly used for diverse applications. Although animal studies suggest CNT/F exposure may cause deleterious health effects, human epidemiological studies have typically been small, confined to single workplaces, and limited in exposure assessment. OBJECTIVES: We conducted an industrywide cross-sectional epidemiological study of 108 workers from 12 U.S. sites to evaluate associations between occupational CNT/F exposure and sputum and blood biomarkers of early effect. METHODS: We assessed CNT/F exposure via personal breathing zone, filter-based air sampling to measure background-corrected elemental carbon (EC) (a CNT/F marker) mass and microscopy-based CNT/F structure count concentrations. We measured 36 sputum and 37 blood biomarkers. We used factor analyses with varimax rotation to derive factors among sputum and blood biomarkers separately. We used linear, Tobit, and unconditional logistic regression models to adjust for potential confounders and evaluate associations between CNT/F exposure and individual biomarkers and derived factors. RESULTS: We derived three sputum and nine blood biomarker factors that explained 78% and 67%, respectively, of the variation. After adjusting for potential confounders, inhalable EC and total inhalable CNT/F structures were associated with the most sputum and blood biomarkers, respectively. Biomarkers associated with at least three CNT/F metrics were 72kDa type IV collagenase/matrix metalloproteinase-2 (MMP-2), interleukin-18, glutathione peroxidase (GPx), myeloperoxidase, and superoxide dismutase (SOD) in sputum and MMP-2, matrix metalloproteinase-9, metalloproteinase inhibitor 1/tissue inhibitor of metalloproteinases 1, 8-hydroxy-2'-deoxyguanosine, GPx, SOD, endothelin-1, fibrinogen, intercellular adhesion molecule 1, vascular cell adhesion protein 1, and von Willebrand factor in blood, although directions of associations were not always as expected. CONCLUSIONS: Inhalable rather than respirable CNT/F was more consistently associated with fibrosis, inflammation, oxidative stress, and cardiovascular biomarkers.

BACKGROUND: There is sparse and inconsistent evidence of an association between styrene exposure and cancer. METHODS: This study examines mortality patterns in a previously studied cohort of 5201 workers employed in two Washington boat-building facilities, extending follow-up 5 years. Standardized mortality ratios (SMR) were calculated using state rates as referent. Cox regression calculated rate ratios (RR) per year employed in styrene-exposed exposed jobs. RESULTS: No excess deaths from lymphohematopoietic cancers (LHCs) were observed (SMR: 0.99, 95%CI: 0.74-1.30) when compared to the referent population; however, the relative risk increased with duration of employment in internal analyses. Conversely, lung cancer mortality was significantly elevated (SMR: 1.24, 95%CI: 1.08-1.41), but there was no evidence of a dose-response relationship. CONCLUSION: We found evidence that occupational exposure to styrene was associated with increased LHC risk, while no such association was observed for lung cancer.

OBJECTIVE: This study leveraged a state workers' compensation claims database and machine learning techniques to target prevention efforts by injury causation and industry. METHODS: Injury causation auto-coding methods were developed to code more than 1.2 million Ohio Bureau of Workers' Compensation claims for this study. Industry groups were ranked for soft-tissue musculoskeletal claims that may have been preventable with biomechanical ergonomic (ERGO) or slip/trip/fall (STF) interventions. RESULTS: On the basis of the average of claim count and rate ranks for more than 200 industry groups, Skilled Nursing Facilities (ERGO) and General Freight Trucking (STF) were the highest risk for lost-time claims (>7 days). CONCLUSION: This study created a third, major causation-specific U.S. occupational injury surveillance system. These findings are being used to focus prevention resources on specific occupational injury types in specific industry groups, especially in Ohio. Other state bureaus or insurers may use similar methods.

BACKGROUND: A cancer incidence analysis was conducted on The National Institute for Occupational Safety and Health boat-builders cohort exposed to styrene, a possible carcinogen. METHODS: Standardized incidence ratios (SIR) and standardized rate ratios (SRR) were calculated using national and Washington State rates and a person-years analysis program. RESULTS: Among 3704 workers living in Washington State after 1991, when cancer registry case accrual began, 516 first primary diagnoses occurred through 2007. While overall cancer incidence was significantly reduced [SIR: 0.83 (0.76, 0.90)], internal comparisons suggest an association with exposure comparing high to low exposed person-time [SRR: 1.28 (1.05, 1.55)]. CONCLUSION: There is evidence of styrene exposure being linked to cancer incidence, which is notable since the cohort has not yet reached the median age of cancer diagnosis (65) in the United States.