Estimating the population prevalence of traditional and novel occupational exposures in Federal Region X.

OBJECTIVE: Federal Region X is an administrative region in the northwestern United States comprised of the states of Alaska (AK), Idaho (ID), Oregon (OR), and Washington (WA). Quantifying the number of workers in this region exposed to harmful circumstances in the workplace, and projected changes over time will help to inform priorities for occupational health training, risk reduction, and research. METHODS: State data for WA, ID, OR, and AK were used to estimate number of workers by occupation, in 2014 and 2024. These data were merged with a Canadian job-exposure matrix (CANJEM) which characterizes chemical exposures, and O*NET, which ranks occupations with particular physical, ergonomic, and psychosocial exposures. RESULTS: Of the exposures considered, psychosocial and ergonomic exposures were the most prevalent among the regional workforce, though traditional chemical exposures are still common and increasing. CONCLUSIONS: Exposure surveillance will inform prioritization of risk reduction strategies, ultimately leading to a decrease in occupational injury and illness. Findings from this analysis will help to prioritize occupational health training and research in the region.

Occupational Exposures and Subclinical Interstitial Lung Disease. The MESA (Multi-Ethnic Study of Atherosclerosis) Air and Lung Studies.

RATIONALE: The impact of a broad range of occupational exposures on subclinical interstitial lung disease (ILD) has not been studied. OBJECTIVES: To determine whether occupational exposures to vapors, gas, dust, and fumes (VGDF) are associated with high-attenuation areas (HAA) and interstitial lung abnormalities (ILA), which are quantitative and qualitative computed tomography (CT)-based measurements of subclinical ILD, respectively. METHODS: We performed analyses of participants enrolled in MESA (Multi-Ethnic Study of Atherosclerosis), a population-based cohort aged 45-84 years at recruitment. HAA was measured at baseline and on serial cardiac CT scans in 5,702 participants. ILA was ascertained in a subset of 2,312 participants who underwent full-lung CT scanning at 10-year follow-up. Occupational exposures were assessed by self-reported VGDF exposure and by job-exposure matrix (JEM). Linear mixed models and logistic regression were used to determine whether occupational exposures were associated with log-transformed HAA and ILA. Models were adjusted for age, sex, race/ethnicity, education, employment status, tobacco use, and scanner technology. MEASUREMENTS AND MAIN RESULTS: Each JEM score increment in VGDF exposure was associated with 2.64% greater HAA (95% confidence interval [CI], 1.23-4.19%). Self-reported vapors/gas exposure was associated with an increased odds of ILA among those currently employed (1.76-fold; 95% CI, 1.09-2.84) and those less than 65 years old (1.97-fold; 95% CI, 1.16-3.35). There was no consistent evidence that occupational exposures were associated with progression of HAA over the follow-up period. CONCLUSIONS: JEM-assigned and self-reported exposures to VGDF were associated with measurements of subclinical ILD in community-dwelling adults.

Hair Manganese as an Exposure Biomarker among Welders.

Quantifying exposure and dose to manganese (Mn) containing airborne particles in welding fume presents many challenges. Common biological markers such as Mn in blood or Mn in urine have not proven to be practical biomarkers even in studies where positive associations were observed. However, hair Mn (MnH) as a biomarker has the advantage over blood and urine that it is less influenced by short-term variability of Mn exposure levels because of its slow growth rate. The objective of this study was to determine whether hair can be used as a biomarker for welders exposed to manganese. Hair samples (1cm) were collected from 47 welding school students and individual air Mn (MnA) exposures were measured for each subject. MnA levels for all days were estimated with a linear mixed model using welding type as a predictor. A 30-day time-weighted average MnA (MnA30d) exposure level was calculated for each hair sample. The association between MnH and MnA30d levels was then assessed. A linear relationship was observed between log-transformed MnA30d and log-transformed MnH. Doubling MnA30d exposure levels yields a 20% (95% confidence interval: 11-29%) increase in MnH. The association was similar for hair washed following two different wash procedures designed to remove external contamination. Hair shows promise as a biomarker for inhaled Mn exposure given the presence of a significant linear association between MnH and MnA30d levels.

Using exposure windows to explore an elusive biomarker: blood manganese.

PURPOSE: We sought to understand the time course between exposure to manganese (Mn) and uptake into the blood, to allow a more meaningful interpretation of exposure biomarker data, and to determine the utility of blood as a biomarker of Mn exposure. METHODS: Welder trainees were monitored over the course of a five-quarter training program. Each quarter, trainees gave eight blood samples and had personal air monitoring four times. A mixed model was fit to obtain estimates of airborne exposure by welding type (fixed effect), adjusted for subject (random effect). Considering weekends and days absent as zero exposure, estimated exposures were summed over various exposure windows and related to measured blood manganese (MnB) using a mixed model. RESULTS: A relationship consistent with zero was found between MnB and modeled 1 or 7 days of exposure. After 30 days of preceding exposure, a 1 mg-days/m(3) increase in air Mn is associated with a 0.57 ng/mL increase in MnB (95% CI -0.04, 1.19). Considering a 90-day exposure window and a cumulative exposure window, a 1 mg-days/m(3) increase in air Mn is associated with a 0.26 (95% CI 0.005, 0.51) and 0.09 (95% CI 0.006, 0.17) ng/mL increase in MnB, respectively. CONCLUSIONS: From this analysis, MnB may begin to act as a biomarker of Mn exposure over longer time periods, or at higher levels of exposure. This novel study design allowed investigation of how MnB relates to different time windows of exposure, representing the most robust Mn exposure assessment in the biomarker literature.

Confined space ventilation by shipyard welders: observed use and effectiveness.

Shipbuilding involves intensive welding activities within enclosed and confined spaces, and although ventilation is commonly used in the industry, its use and effectiveness has not been adequately documented. Workers engaged in welding in enclosed or confined spaces in two shipyards were observed for their use of ventilation and monitored for their exposure to particulate matter. The type of ventilation in use, its placement and face velocity, the movement of air within the space, and other ventilation-related parameters were recorded, along with task characteristics such as the type of welding, the welder's position, and the configuration of the space. Mechanical ventilation was present in about two-thirds of the 65 welding scenarios observed, with exhaust ventilation used predominantly in one shipyard and supply blowers predominantly in the other. Welders were observed working in apparent dead-spaces within the room in 53% of the cases, even where ventilation was in use. Respiratory protection was common in the two shipyards, observed in use in 77 and 100% of the cases. Welding method, the proximity of the welder's head to the fume, and air mixing were found to be significantly associated with the welder's exposure, while other characteristics of dilution ventilation did not produce appreciable differences in exposure level. These parameters associated with exposure reduction can be assessed subjectively and are thus good candidates for training on effective ventilation use during hot work in confined spaces. Ventilation used in confined space welding is often inadequate for controlling exposure to welding fume.

Blood manganese as an exposure biomarker: state of the evidence.

Despite evidence of adverse health effects resulting from exposure to manganese (Mn), biomarkers of exposure are poorly understood. To enhance understanding, mean blood Mn (MnB) and mean air Mn (MnA) were extracted from 63 exposure groups in 24 published papers, and the relationship was modeled using segmented regression. On a log/log scale, a positive association between MnA and MnB was observed among studies reporting MnA concentrations above about 10 µg/m(3), although interpretation is limited by largely cross-sectional data, study design variability, and differences in exposure monitoring methods. Based on the results of the segmented regression, we hypothesize that below the concentration of about 10 µg/m(3), Mn in the body is dominated by dietary Mn, and additional inhaled Mn only causes negligible changes in Mn levels unless the inhaled amount is substantial. However, stronger study designs are required to account for temporal characteristics of the MnA to MnB relationships that reflect the underlying physiology and toxicokinetics of Mn uptake and distribution. Thus, we present an inception cohort study design we have conducted among apprentice welders, and the analytical strengths this study design offers. To determine if blood could be a useful biomarker for Mn to be utilized by industrial hygienists in general industry requires additional time-specific analyses, which our inception cohort study design will allow.

Occupational factors associated with burnout among a sample of 9-1-1 public safety telecommunicators in Washington State.

INTRODUCTION: This study aimed to investigate occupational factors associated with burnout among a sample of 9-1-1 public safety telecommunicators (PSTs). METHODS: An online survey measuring organizational factors (i.e., perceived visibility and inclusion in the agency, respectful culture, leadership support, perceived gratitude, and co-worker conflict); job characteristics (i.e., work-life integration, overtime, salary satisfaction, and job meaningfulness); burnout, demographic and call center characteristics, was emailed to a sample of PSTs.AnalysisDescriptive, bivariate, and multiple linear regression analyses were used to characterize the sample and investigate relationships among variables. RESULTS: N = 324 PSTs completed the survey. Multi-variate analysis showed that poor work-life integration and coworker conflict were associated with greater PST burnout, while job meaningfulness and perceptions of greater visibility and inclusion were linked to decreased levels of burnout. CONCLUSION: Occupational factors were associated with burnout among PSTs.

Protecting our science.

In response to a recent court decision, the Annals of Occupational Hygiene is reviewing our procedures to ensure transparency in authorship and direct and indirect conflicts of interest. These improvements are intended to help protect the integrity of the science presented in the journal.

Work-Related Factors Associated With Health and Well-Being of Early Care and Education Workers.

OBJECTIVE: We assessed and examined relationships between the health and working conditions of early care and education workers. METHODS: We surveyed early care and education workers ( n = 2242) about their socioeconomic characteristics; work organization; psychosocial, physical, and ergonomic exposures; coping behaviors; and health. RESULTS: Nearly half of respondents reported chronic health conditions. Most worked full time, half earned less than $30,000 a year, and many reported unpaid hours or inability to take breaks. One-quarter reported economic strain. Numerous exposures were prevalent. Workers' general health was poorer than normed averages, although their physical functioning was slightly better. Sixteen percent of workers reported work-related injuries, and 43% reported depressive symptoms. Factors associated with health included socioeconomic characteristics, having a chronic condition, job type, access to benefits, eight psychosocial stressors, four physical exposures, sleep, and alcohol consumption. CONCLUSIONS: Findings support the need for attention to this workforce's health.

10-Year prospective study of noise exposure and hearing damage among construction workers.

OBJECTIVES: To characterise the effects of noise exposure, including intermittent and peaky exposure, on hearing damage as assessed by standard pure-tone thresholds and otoacoustic emissions, a longitudinal study was conducted on newly hired construction apprentices and controls over a 10-year period. METHODS: Among the 456 subjects recruited at baseline, 316 had at least two (mean 4.6) examinations and were included in this analysis. Annual examinations included hearing threshold levels (HTLs) for air conducted pure tones and distortion product otoacoustic emission (DPOAE) amplitudes. Task-based occupational noise exposure levels and recreational exposures were estimated. Linear mixed models were fit for HTLs and DPOAEs at 3, 4 and 6 kHz in relation to time since baseline and average noise level since baseline, while controlling for hearing level at baseline and other risk factors. RESULTS: Estimated L(EQ) noise exposures were 87±3.6 dBA among the construction workers. Linear mixed modelling demonstrated significant exposure-related elevations in HTL of about 2-3 dB over a projected 10-year period at 3, 4 or 6 kHz for a 10 dB increase in exposure. The DPOAE models (using L1=40) predicted about 1 dB decrease in emission amplitude over 10 years for a 10 dB increase in exposure. CONCLUSIONS: The study provides evidence of noise-induced damage at an average exposure level around the 85 dBA level. The predicted change in HTLs was somewhat higher than would be predicted by standard hearing loss models, after accounting for hearing loss at baseline. Limited evidence for an enhanced effect of high peak component noise was observed, and DPOAEs, although similarly affected, showed no advantage over standard hearing threshold evaluation in detecting effects of noise on the ear and hearing.

Early Care and Education Workers' Experience and Stress during the COVID-19 Pandemic.

Early care and education (ECE) workers experience many job-related stressors. During the COVID-19 pandemic, ECE programs either closed or remained open while workers faced additional demands. We deployed a survey of the center-based ECE workforce in Washington State (United States) one year into the COVID-19 pandemic to assess impacts and workers' perceived stress levels. We describe the prevalence of reported impacts, including workplace closures; job changes; COVID-19 transmission; risk factors for severe COVID-19; the use of social distancing practices; satisfaction with workplace responses; perceptions of worker roles, respect, and influence; and food and financial insecurity. Themes from open-ended responses illustrate how workers' jobs changed and the stressors that workers experienced as a result. Fifty-seven percent of ECE workers reported moderate or high levels of stress. In a regression model assessing unique contributions to stress, work changes that negatively impacted home life contributed most to stress. Feeling respected for one's work and feeling positive about one's role as an "essential worker" contributed to lower levels of stress. Experiencing financial insecurity, caring for school-aged children or children of multiple ages, being younger, and being born in the United States also contributed to higher stress. Findings can inform policies designed to support the workforce.

Do Different Patterns of Employment Quality Contribute to Gender Health Inequities in the U.S.? A Cross-Sectional Mediation Analysis.

Compared to recent generations, workers today generally experience poorer quality employment across both contractual (e.g., wages, hours) and relational (e.g., participation in decision-making, power dynamics) dimensions within the worker-employer relationship. Recent research shows that women are more likely to experience poor-quality employment and that these conditions are associated with adverse health effects, suggesting employment relations may contribute to gender inequities in health. We analyzed data from the General Social Survey (2002-2018) to explore whether the multidimensional construct of employment quality (EQ) mediates the relationship between gender and health among a representative, cross-sectional sample of U.S. wage earners. Using a counterfactually-based causal mediation framework, we found that EQ plays a meaningful role in a gender-health relationship, and that if the distribution of EQ among women was equal to that observed in men, the probability of reporting poor self-reported health and frequent mental distress among women would be lower by 1.5% (95% Confidence Interval: 0.5-2.8%) and 2.6% (95% CI: 0.6-4.6%), respectively. Our use of a multidimensional, typological measure of EQ allowed our analysis to better account for substantial heterogeneity in the configuration of contemporary employment arrangements. Additionally, this study is one of the first mediation analyses with a nominal mediator within the epidemiologic literature. Our results highlight EQ as a potential target for intervention to reduce gender inequities in health.

What does non-standard employment look like in the United States? An empirical typology of employment quality.

Despite significant interest in the changing nature of employment as a critical social and economic challenge facing society-especially the decline in the so-called Standard Employment Relationship (SER) and rise in more insecure, precarious forms of employment-scholars have struggled to operationalize the multifaceted and heterogeneous nature of contemporary worker-employer relationships within empirical analyses. Here we investigate the character and distribution of employment relationships in the U.S., drawing on a representative sample of wage-earners and self-employed from the General Social Survey (2002 - 2018). We use the multidimensional construct of employment quality (EQ), which includes both contractual (e.g., wages, contract type) and relational (e.g., employee representation and participation) aspects of employment. We further employ a typological measurement approach, using latent class analysis, to explicitly examine how the multiple aspects of employment cluster together in modern labor markets. We present eight distinct employment types in the U.S., including one resembling the historical conception of the SER model (24% of the total workforce), and others representing various constellations of favorable and adverse employment features. These employment types are unevenly distributed across society, in terms of who works these jobs and where they are found in the labor market. Importantly, women, those with lower education, and younger workers are more likely to be in precarious forms of employment. More generally, our typology reveals limitations associated with binary conceptions of standard vs. non-standard employment, or insider-outsider dichotomies envisioned within dual labor market theories.

The relationship between multiple myeloma and occupational exposure to six chlorinated solvents.

OBJECTIVES: Few studies have examined whether exposure to chlorinated solvents is associated with multiple myeloma. We evaluated associations between multiple myeloma and occupational exposure to six chlorinated solvents: 1,1,1-trichloroethane, trichloroethylene (TCE), methylene chloride (DCM), perchloroethylene, carbon tetrachloride and chloroform. METHODS: In-person interviews obtained occupational histories and information on jobs with likely solvent exposure. We assigned exposure metrics of probability, frequency, intensity and confidence using job-exposure matrices modified by job-specific questionnaire information. We used logistic regression to estimate ORs and 95% CIs for associations between multiple myeloma and ever exposure to each, and any, chlorinated solvent and analysed whether associations varied by duration and cumulative exposure. We also considered all occupations that were given the lowest confidence scores as unexposed and repeated all analyses. RESULTS: Risk of multiple myeloma was elevated for subjects ever exposed to 1,1,1-trichloroethane (OR (95% CI): 1.8 (1.1 to 2.9)). Ever exposure to TCE or DCM also entailed elevated, but not statistically significant, risks of multiple myeloma; these became statistically significant when occupations with low confidence scores were considered unexposed (TCE: 1.7 (1.0 to 2.7); DCM: 2.0 (1.2 to 3.2)). Increasing cumulative exposure to perchloroethylene was also associated with increasing multiple myeloma risk. We observed non-significantly increased multiple myeloma risks with exposure to chloroform; however, few subjects were exposed. CONCLUSIONS: Evidence from this relatively large case-control study suggests that exposures to certain chlorinated solvents may be associated with increased incidence of multiple myeloma; however, the study is limited by relatively low participation (52%) among controls.

Longitudinal assessment of noise exposure in a cohort of construction workers.

OBJECTIVES: To address questions surrounding noise-induced hearing loss (NIHL) from variable noise, we have been evaluating noise exposures and changes in hearing in a prospective cohort of construction workers (representing eight trades) and controls. In this paper, we develop and explore several long-term exposure estimates for cohort members. METHODS: We followed cohort members between 1999 and 2009 and interviewed them approximately annually to obtain a detailed work history for the previous subject-interval while also collecting tests of hearing sensitivity. Over the same period, we also collected a sample of full-shift average noise measurements and activity information. We used data from these two sources to develop various exposure estimates for each subject for specific subject intervals and for the duration of the study. These estimates included work duration, trade-mean (TM)-equivalent continuous exposure level (L(EQ)), task-based (TB) L(EQ), a hybrid L(EQ) combining TB and subjective information, and an estimate of noise exposure 'peakiness'. RESULTS: Of the 456 subjects enrolled in the study, 333 had at least 2 interviews and met several inclusion criteria related to hearing sensitivity. Depending on the metric used, between one-third and three-quarters of 1310 measured full-shift noise exposures exceeded permissible and recommended exposure limits. Hybrid and TB exposure estimates demonstrated much greater variability than TM estimates. Work duration and estimates of exposure peakiness showed poor agreement with average exposures, suggesting that these metrics evaluate different aspects of exposure and may have different predictive value for estimating NIHL. CONCLUSIONS: Construction workers in the cohort had subject-interval and study-average exposures which present a substantial potential risk of NIHL. In a subsequent paper, we will use these estimates to evaluate the exposure-response relationship between noise and NIHL.

Estimation of particulate mass and manganese exposure levels among welders.

BACKGROUND: Welders are frequently exposed to Manganese (Mn), which may increase the risk of neurological impairment. Historical exposure estimates for welding-exposed workers are needed for epidemiological studies evaluating the relationship between welding and neurological or other health outcomes. The objective of this study was to develop and validate a multivariate model to estimate quantitative levels of welding fume exposures based on welding particulate mass and Mn concentrations reported in the published literature. METHODS: Articles that described welding particulate and Mn exposures during field welding activities were identified through a comprehensive literature search. Summary measures of exposure and related determinants such as year of sampling, welding process performed, type of ventilation used, degree of enclosure, base metal, and location of sampling filter were extracted from each article. The natural log of the reported arithmetic mean exposure level was used as the dependent variable in model building, while the independent variables included the exposure determinants. Cross-validation was performed to aid in model selection and to evaluate the generalizability of the models. RESULTS: A total of 33 particulate and 27 Mn means were included in the regression analysis. The final model explained 76% of the variability in the mean exposures and included welding process and degree of enclosure as predictors. There was very little change in the explained variability and root mean squared error between the final model and its cross-validation model indicating the final model is robust given the available data. CONCLUSIONS: This model may be improved with more detailed exposure determinants; however, the relatively large amount of variance explained by the final model along with the positive generalizability results of the cross-validation increases the confidence that the estimates derived from this model can be used for estimating welder exposures in absence of individual measurement data.

Improving exposure estimates by combining exposure information.

OBJECTIVES: Any exposure estimation technique has inherent strengths and limitations. In an effort to improve exposure estimates, this study developed and evaluated the performance of several hybrid exposure estimates created by combining information from individual assessment techniques. METHODS: Construction workers (n = 68) each completed three full-shift noise measurements over 4 months. Three single exposure assessment techniques [trade mean (TM), task-based (TB), and subjective rating (SR)] were used to estimate exposures for each subject. Hybrid techniques were then developed which incorporated the TM, SR, and TB noise exposure estimates via arithmetic mean combination, linear regression combination, and modification of TM and TB estimates using SR information. Exposure estimates from the single and hybrid techniques were compared to subjects' measured exposures to evaluate accuracy. RESULTS: Hybrid estimates generally were more accurate than estimates from single techniques. The best-performing hybrid techniques combined TB and SR estimates and resulted in improvements in estimated exposures compared to single techniques. Hybrid estimates were not improved by the inclusion of TM information in this study. CONCLUSIONS: Hybrid noise exposure estimates performed better than individual estimates, and in this study, combination of TB and SR estimates using linear regression performed best. The application of hybrid approaches in other contexts will depend upon the exposure of interest and the nature of the individual exposure estimates available.

A multi-component intervention to promote hearing protector use among construction workers.

Hearing protection devices (HPD) remain a primary method of prevention of noise-induced hearing loss despite their well-known limitations. A three-pronged intervention to increase HPD use was conducted among construction workers and included a baseline hearing loss prevention training, follow-up 'toolbox' (TB) reinforcement trainings, and use of a personal noise level indicator (NLI). A total of 176 subjects on eight sites completed three assessments. Prior to intervention, HPDs were used an average of 34.5% of the time and increased significantly, up about 12.1% after intervention and 7.5% two months after interventions were completed. The increase in HPD use was greatest among the group receiving both TB and NLI interventions; up about 25% from baseline, and this group was about two times more likely to use HPDs than the BL (baseline) training only group. This study demonstrates the mild impact of a well-constructed HPD use training and provides support for the additional use of a personal NLI to increase use of HPDs among construction workers. The most effective procedures for using such instruments require further exploration.