Excess mortality among essential workers in England and Wales during the COVID-19 pandemic: an updated analysis

BACKGROUND

Excess mortality from all causes combined during the COVID-19 pandemic in England and Wales in 2020 was predominantly higher for essential workers. In 2021, the vaccination programme had begun, new SARS-CoV-2 variants were identified and different policy approaches were used. We have updated our previous analyses of excess mortality in England and Wales to include trends in excess mortality by occupation for 2021.

METHODS

We estimated excess mortality for working age adults living in England and Wales by occupational group for each month in 2021 and for the year as a whole.

RESULTS

During 2021, excess mortality remained higher for most groups of essential workers than for non-essential workers. It peaked in January 2021 when all-cause mortality was 44.6% higher than expected for all occupational groups combined. Excess mortality was highest for adults working in social care (86.9% higher than expected).

CONCLUSION

Previously, we reported excess mortality in 2020, with this paper providing an update to include 2021 data. Excess mortality was predominantly higher for essential workers during 2021. However, unlike the first year of the pandemic, when healthcare workers experienced the highest mortality, the highest excess mortality during 2021 was experienced by social care workers.

Between-occupation differences in work-related COVID-19 mitigation strategies over time: Analysis of the Virus Watch Cohort in England and Wales

OBJECTIVES

COVID-19 mitigations have had a profound impact on workplaces, however, multisectoral comparisons of how work-related mitigations were applied are limited. This study aimed to investigate (i) occupational differences in the usage of key work-related mitigations over time and (ii) workers' perceptions of these mitigations.

METHODS

Employed/self-employed Virus Watch study participants (N=6279) responded to a mitigation-related online survey covering the periods of December 2020-February 2022. Logistic regression was used to investigate occupation- and time-related differences in the usage of work-related mitigation methods. Participants' perceptions of mitigation methods were investigated descriptively using proportions.

RESULTS

Usage of work-related mitigation methods differed between occupations and over time, likely reflecting variation in job roles, workplace environments, legislation and guidance. Healthcare workers had the highest predicted probabilities for several mitigations, including reporting frequent hand hygiene [predicted probability across all survey periods 0.61 (95% CI 0.56-0.66)] and always wearing face coverings [predicted probability range 0.71 (95% CI 0.66-0.75) - 0.80 (95% CI 0.76-0.84) across survey periods]. There were significant cross-occupational trends towards reduced mitigations during periods of less stringent national restrictions. The majority of participants across occupations (55-88%) agreed that most mitigations were reasonable and worthwhile even after the relaxation of national restrictions; agreement was lower for physical distancing (39-44%).

CONCLUSIONS

While usage of work-related mitigations appeared to vary alongside stringency of national restrictions, agreement that most mitigations were reasonable and worthwhile remained substantial. Further investigation into the factors underlying between-occupational differences could assist pandemic planning and prevention of workplace COVID-19 transmission.

Differential Risk of SARS-CoV-2 Infection by Occupation: Evidence from the Virus Watch prospective cohort study in England and Wales

BACKGROUND

Workers across different occupations vary in their risk of SARS-CoV-2 infection, but the direct contribution of occupation to this relationship is unclear. This study aimed to investigate how infection risk differed across occupational groups in England and Wales up to April 2022, after adjustment for potential confounding and stratification by pandemic phase.

METHODS

Data from 15,190 employed/self-employed participants in the Virus Watch prospective cohort study were used to generate risk ratios for virologically- or serologically-confirmed SARS-CoV-2 infection using robust Poisson regression, adjusting for socio-demographic and health-related factors and non-work public activities. We calculated attributable fractions (AF) amongst the exposed for belonging to each occupational group based on adjusted risk ratios (aRR).

RESULTS

Increased risk was seen in nurses (aRR = 1.44, 1.25-1.65; AF = 30%, 20-39%), doctors (aRR = 1.33, 1.08-1.65; AF = 25%, 7-39%), carers (1.45, 1.19-1.76; AF = 31%, 16-43%), primary school teachers (aRR = 1.67, 1.42- 1.96; AF = 40%, 30-49%), secondary school teachers (aRR = 1.48, 1.26-1.72; AF = 32%, 21-42%), and teaching support occupations (aRR = 1.42, 1.23-1.64; AF = 29%, 18-39%) compared to office-based professional occupations. Differential risk was apparent in the earlier phases (Feb 2020-May 2021) and attenuated later (June-October 2021) for most groups, although teachers and teaching support workers demonstrated persistently elevated risk across waves.

CONCLUSIONS

Occupational differences in SARS-CoV-2 infection risk vary over time and are robust to adjustment for socio-demographic, health-related, and non-workplace activity-related potential confounders. Direct investigation into workplace factors underlying elevated risk and how these change over time is needed to inform occupational health interventions.

Occupation, Worker Vulnerability, and COVID-19 Vaccination Uptake: Analysis of the Virus Watch prospective cohort study

BACKGROUND

Occupational disparities in COVID-19 vaccine uptake can impact the effectiveness of vaccination programmes and introduce particular risk for vulnerable workers and those with high workplace exposure. This study aimed to investigate COVID-19 vaccine uptake by occupation, including for vulnerable groups and by occupational exposure status.

METHODS

We used data from employed or self-employed adults who provided occupational information as part of the Virus Watch prospective cohort study (n = 19,595) and linked this to study-obtained information about vulnerability-relevant characteristics (age, medical conditions, obesity status) and work-related COVID-19 exposure based on the Job Exposure Matrix. Participant vaccination status for the first, second, and third dose of any COVID-19 vaccine was obtained based on linkage to national records and study records. We calculated proportions and Sison-Glaz multinomial 95% confidence intervals for vaccine uptake by occupation overall, by vulnerability-relevant characteristics, and by job exposure.

FINDINGS

Vaccination uptake across occupations ranged from 89-96% for the first dose, 87-94% for the second dose, and 75-86% for the third dose, with transport, trade, service and sales workers persistently demonstrating the lowest uptake. Vulnerable workers tended to demonstrate fewer between-occupational differences in uptake than non-vulnerable workers, although clinically vulnerable transport workers (76%-89% across doses) had lower uptake than several other occupational groups (maximum across doses 86%-96%). Workers with low SARS-CoV-2 exposure risk had higher vaccine uptake (86%-96% across doses) than those with elevated or high risk (81-94% across doses).

INTERPRETATION

Differential vaccination uptake by occupation, particularly amongst vulnerable and highly-exposed workers, is likely to worsen occupational and related socioeconomic inequalities in infection outcomes. Further investigation into occupational and non-occupational factors influencing differential uptake is required to inform relevant interventions for future COVID-19 booster rollouts and similar vaccination programmes.

Exploring Associations between Stressors and Burnout in Trainee Doctors During the COVID-19 Pandemic in the UK

OBJECTIVE

The authors examined associations between stressors and burnout in trainee doctors during the COVID-19 pandemic.

METHODS

An anonymous online questionnaire including 42 questions on general and pandemic-specific stressors, and the Maslach Burnout Inventory-Health Services Survey (MBI-HSS), was sent to 1000 randomly selected trainee doctors in North-West England. Main outcomes were burnout scores that were stratified into Emotional Exhaustion (EE), Depersonalisation (DP), and reduced Personal Accomplishment (PA) and associations between stressors and burnout using stepwise regression analysis.

RESULTS

A total of 362 complete responses were received giving a response rate of 37%. Mean scores for EE, DP, and PA derived from the MBI-HSS were 27.7, 9.8, and 34.3 respectively. Twenty-three stressors were found to be associated with burnout dimensions. "Increase in workload and hours due to COVID-19," "Poor leadership and management in the National Health Service," and "Not feeling valued" were found to have strong associations with burnout dimensions. Only "Not confident in own abilities" was found to be associated with all burnout dimensions.

CONCLUSIONS

Associations with burnout were found to be identified in a range of work, pandemic, and non-work-related stressors, supporting the need for multi-level interventions to mitigate burnout.

Mitigating the impact of air pollution on dementia and brain health: Setting the policy agenda

BACKGROUND

Emerging research suggests exposure to high levels of air pollution at critical points in the life-course is detrimental to brain health, including cognitive decline and dementia. Social determinants play a significant role, including socio-economic deprivation, environmental factors and heightened health and social inequalities. Policies have been proposed more generally, but their benefits for brain health have yet to be fully explored.

OBJECTIVE AND METHODS

Over the course of two years, we worked as a consortium of 20+ academics in a participatory and consensus method to develop the first policy agenda for mitigating air pollution's impact on brain health and dementia, including an umbrella review and engaging 11 stakeholder organisations.

RESULTS

We identified three policy domains and 14 priority areas. Research and Funding included: (1) embracing a complexities of place approach that (2) highlights vulnerable populations; (3) details the impact of ambient PM_2.5 on brain health, including current and historical high-resolution exposure models; (4) emphasises the importance of indoor air pollution; (5) catalogues the multiple pathways to disease for brain health and dementia, including those most at risk; (6) embraces a life course perspective; and (7) radically rethinks funding. Education and Awareness included: (8) making this unrecognised public health issue known; (9) developing educational products; (10) attaching air pollution and brain health to existing strategies and campaigns; and (11) providing publicly available monitoring, assessment and screening tools. Policy Evaluation included: (12) conducting complex systems evaluation; (13) engaging in co-production; and (14) evaluating air quality policies for their brain health benefits.

CONCLUSION

Given the pressing issues of brain health, dementia and air pollution, setting a policy agenda is crucial. Policy needs to be matched by scientific evidence and appropriate guidelines, including bespoke strategies to optimise impact and mitigate unintended consequences. The agenda provided here is the first step toward such a plan.

Longitudinal changes in proportionate mortality due to COVID-19 by occupation in England and Wales

OBJECTIVE

This study aimed to understand whether the proportionate mortality of COVID-19 for various occupational groups has varied over the pandemic.

METHODS

We used the Office for National Statistics (ONS) mortality data for England and Wales. The deaths (20-64 years) were classified as either COVID-19-related using ICD-10 codes (U07.1, U07.2), or from other causes. Occupational data recorded at the time of death was coded using the SOC10 coding system into 13 groups. Three time periods (TP) were used: (i) January 2020 to September 2020; (ii) October 2020-May 2021; and (iii) June 2021-October 2021. We analyzed the data with logistic regression and compared odds of death by COVID-19 to other causes, adjusting for age, sex, deprivation, region, urban/rural and population density.

RESULTS

Healthcare professionals and associates had a higher proportionate odds of COVID-19 death in TP1 compared to non-essential workers but were not observed to have increased odds thereafter. Medical support staff had increased odds of death from COVID-19 during both TP1 and TP2, but this had reduced by TP3. This latter pattern was also seen for social care, food retail and distribution, and bus and coach drivers. Taxi and cab drivers were the only group that had higher odds of death from COVID-19 compared to other causes throughout the whole period under study [TP1: odds ratio (OR) 2.42, 95% confidence interval (CI) 1.99-2.93; TP2: OR 3.15, 95% CI 2.63-3.78; TP3: OR 1.7, 95% CI 1.26-2.29].

CONCLUSION

Differences in the odds of death from COVID-19 between occupational groups has declined over the course of the pandemic, although some occupations have remained relatively high throughout.

Paternal Occupational Exposure to Heavy Metals and Welding Fumes and Testicular Germ Cell Tumours in Sons in France

Testicular cancer is the most common cancer in young men. Its causes are largely unknown, although prenatal occupational and environmental exposures have been suggested. We investigated paternal occupational exposure to heavy metals and welding fumes and the risk of testicular germ cell tumors (TGCT) in their offspring. A total of 454 cases and 670 controls were included from a French nationwide case-control study. The INTEROCC job exposure matrix was used to assign occupational exposures (cadmium, chromium, iron, nickel, lead, and welding fumes) to the fathers' jobs. Odds ratios (ORs) for TGCT were estimated using conditional logistic regression models for frequency-matched sets. Three complementary analytical approaches were used: (1) single-agent analysis, (2) analysis by groups, and (3) principal component analysis (PCA). The proportion of paternal exposure to different heavy metals and welding fumes ranged from 0.7% (cadmium) to 11.3% (lead). Based on PCA, three principal components explained 93.5% of the cumulative variance. No associations were found between heavy metals or welding fumes and TGCT. In this study, paternal occupational exposure to heavy metals or welding fumes was not associated with TGCT development in their sons.

Occupational differences in SARS-CoV-2 infection: analysis of the UK ONS COVID-19 infection survey

BACKGROUND

Concern remains about how occupational SARS-CoV-2 risk has evolved during the COVID-19 pandemic. We aimed to ascertain occupations with the greatest risk of SARS-CoV-2 infection and explore how relative differences varied over the pandemic.

METHODS

Analysis of cohort data from the UK Office of National Statistics COVID-19 Infection Survey from April 2020 to November 2021. This survey is designed to be representative of the UK population and uses regular PCR testing. Cox and multilevel logistic regression were used to compare SARS-CoV-2 infection between occupational/sector groups, overall and by four time periods with interactions, adjusted for age, sex, ethnicity, deprivation, region, household size, urban/rural neighbourhood and current health conditions.

RESULTS

Based on 3 910 311 observations (visits) from 312 304 working age adults, elevated risks of infection can be seen overall for social care (HR 1.14; 95% CI 1.04 to 1.24), education (HR 1.31; 95% CI 1.23 to 1.39), bus and coach drivers (1.43; 95% CI 1.03 to 1.97) and police and protective services (HR 1.45; 95% CI 1.29 to 1.62) when compared with non-essential workers. By time period, relative differences were more pronounced early in the pandemic. For healthcare elevated odds in the early waves switched to a reduction in the later stages. Education saw raises after the initial lockdown and this has persisted. Adjustment for covariates made very little difference to effect estimates.

CONCLUSIONS

Elevated risks among healthcare workers have diminished over time but education workers have had persistently higher risks. Long-term mitigation measures in certain workplaces may be warranted.

Workplace contact patterns in England during the COVID-19 pandemic: Analysis of the Virus Watch prospective cohort study

Background

Workplaces are an important potential source of SARS-CoV-2 exposure; however, investigation into workplace contact patterns is lacking. This study aimed to investigate how workplace attendance and features of contact varied between occupations across the COVID-19 pandemic in England.

Methods

Data were obtained from electronic contact diaries (November 2020-November 2021) submitted by employed/self-employed prospective cohort study participants (n=4,616). We used mixed models to investigate the effects of occupation and time for: workplace attendance, number of people sharing workspace, time spent sharing workspace, number of close contacts, and usage of face coverings.

Findings

Workplace attendance and contact patterns varied across occupations and time. The predicted probability of intense space sharing during the day was highest for healthcare (78% [95% CI: 75-81%]) and education workers (64% [59%-69%]), who also had the highest probabilities for larger numbers of close contacts (36% [32%-40%] and 38% [33%-43%] respectively). Education workers also demonstrated relatively low predicted probability (51% [44%-57%]) of wearing a face covering during close contact. Across all occupational groups, workspace sharing and close contact increased and usage of face coverings decreased during phases of less stringent restrictions.

Interpretation

Major variations in workplace contact patterns and mask use likely contribute to differential COVID-19 risk. Patterns of variation by occupation and restriction phase may inform interventions for future waves of COVID-19 or other respiratory epidemics. Across occupations, increasing workplace contact and reduced face covering usage is concerning given ongoing high levels of community transmission and emergence of variants.

Funding

Medical Research Council; HM Government; Wellcome Trust.

Cross-sectional study exploring the association between stressors and burnout in junior doctors during the COVID-19 pandemic in the United Kingdom

OBJECTIVES

This study aims to develop a comprehensive list of stressors relevant to junior doctors and will also report findings exploring the associations between burnout and stressors, which include work and non-work-related stressors as well as pandemic-related stressors.

METHODS

An anonymous online questionnaire was sent to 1000 randomly selected junior doctors in the North-West of England. The questionnaire included 37 questions on general and pandemic-specific stressors, and the Maslach Burnout Inventory Health Services Survey. The main outcomes of interest were junior doctor ratings of stressors and scores for burnout (emotional exhaustion [EE], depersonalisation [DP], and personal accomplishment [PA]). Stepwise regression analysis was undertaken to assess associations between stressors and burnout.

RESULTS

In total, 326 responses were collected (response rate = 33%). Of the top 10 stressors rated by junior doctors, 60% were related to the pandemic. Multiple stressors were found to be associated with the burnout dimensions. Fatigue (β = .43), pandemic-related workload increase (β = .33), and feeling isolated (β = .24) had the strongest associations with EE, whereas fatigue (β = .21), uncertainty around COVID-19 information (β = .22) and doing unproductive tasks (β = .17) had the strongest associations with DP. Working beyond normal scope due to COVID-19 (β = -.26), not confident in own ability (β = -.24) and not feeling valued (β = -.20) were found to have the strongest associations with PA.

CONCLUSIONS

Junior doctors experience a combination of general stressors and additional stressors emerging from the pandemic which significantly impact burnout. Monitoring these stressors and targeting them as part of interventions could help mitigating burnout in junior doctors.

Factors Associated With Burnout and Stress in Trainee Physicians: A Systematic Review and Meta-analysis

IMPORTANCE

Evidence suggests that physicians experience high levels of burnout and stress and that trainee physicians are a particularly high-risk group. Multiple workplace- and non-workplace-related factors have been identified in trainee physicians, but it is unclear which factors are most important in association with burnout and stress. Better understanding of the most critical factors could help inform the development of targeted interventions to reduce burnout and stress.

OBJECTIVE

To estimate the association between different stressors and burnout/stress among physicians engaged in standard postgraduate training (ie, trainee physicians).

DATA SOURCES

Medline, Embase, PsycINFO, and Cochrane Database of Systematic reviews from inception until April 30, 2019. Search terms included trainee, foundation year, registrar, resident, and intern.

STUDY SELECTION

Studies that reported associations between stressors and burnout/stress in trainee physicians.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted the data and assessed the quality of the evidence. The main meta-analysis was followed by sensitivity analyses. All analyses were performed using random-effects models, and heterogeneity was quantified using the I2 statistic.

MAIN OUTCOME AND MEASURES

The main outcome was the association between burnout/stress and workplace- or non-workplace-related factors reported as odds ratios (ORs) and their 95% CIs.

RESULTS

Forty-eight studies were included in the meta-analysis (n = 36 266, median age, 29 years [range, 24.6-35.7 years]). One study did not specify participants' sex; of the total population, 18 781 participants (52%) were men. In particular, work demands of a trainee physician were associated with a nearly 3-fold increased odds for burnout/stress (OR, 2.84; 95% CI, 2.26-3.59), followed by concerns about patient care (OR, 2.35; 95% CI, 1.58-3.50), poor work environment (OR, 2.06; 95% CI, 1.57-2.70), and poor work-life balance (OR, 1.93; 95% CI, 1.53-2.44). Perceived/reported poor mental or physical health (OR, 2.41; 95% CI, 1.76-3.31), female sex (OR, 1.34; 95% CI, 1.20-1.50), financial worries (OR, 1.35; 95% CI, 1.07-1.72), and low self-efficacy (OR, 2.13; 95% CI, 1.31-3.46) were associated with increased odds for burnout/stress, whereas younger age and a more junior grade were not significantly associated.

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that the odds ratios for burnout and stress in trainee physicians are higher than those for work-related factors compared with nonmodifiable and non-work-related factors, such as age and grade. These findings support the need for organizational interventions to mitigate burnout in trainee physicians.

A Qualitative Study Exploring the Determinants, Coping, and Effects of Stress in United Kingdom Trainee Doctors

OBJECTIVES

Evidence suggests United Kingdom trainee doctors are experiencing high levels of stress; however, little is known about what determinants contribute to stress, coping mechanisms to mitigate stress, and the effects of stress are in current trainee doctors. Hence, this study aims to explore the determinants, coping mechanisms as well as the effects of stress in this group.

METHODS

Focus groups were undertaken with trainee doctors in North West England to better understand the determinants, coping mechanisms, and effects of stress. Informed written consent was obtained and focus groups were recorded and transcribed. Transcriptions were analyzed using QSR NVivo v11.

RESULTS

A total of 44 trainee doctors participated in 11 focus groups. Respondents comprised UK graduates and international medical graduates, across all stages of training in a range of different specialties. Four main themes were identified as determinants: (1) Expectations and guilt, (2) Feeling undervalued, (3) Managing uncertainty and risk, (4) Work environment. Four main themes were identified as coping mechanisms: (1) Reflection and insight, (2) Work-life balance, (3) Work and training environment, (4) Development as a doctor. Two main themes were identified as effects of stress: (1) Negative outcome on wellbeing, (2) Outcome on career.

CONCLUSIONS

A range of determinants contributes to stress in trainee doctors and they utilize a range of mechanisms to cope. Stress in their working lives can also affect their wellbeing and careers. These findings could be used to improve the understanding of stress in trainee doctors and assist in the development of supportive interventions.

Between-User Reliability of Tier 1 Exposure Assessment Tools Used Under REACH

When applying simple screening (Tier 1) tools to estimate exposure to chemicals in a given exposure situation under the Registration, Evaluation, Authorisation and restriction of CHemicals Regulation 2006 (REACH), users must select from several possible input parameters. Previous studies have suggested that results from exposure assessments using expert judgement and from the use of modelling tools can vary considerably between assessors. This study aimed to investigate the between-user reliability of Tier 1 tools. A remote-completion exercise and in person workshop were used to identify and evaluate tool parameters and factors such as user demographics that may be potentially associated with between-user variability. Participants (N = 146) generated dermal and inhalation exposure estimates (N = 4066) from specified workplace descriptions ('exposure situations') and Tier 1 tool combinations (N = 20). Interactions between users, tools, and situations were investigated and described. Systematic variation associated with individual users was minor compared with random between-user variation. Although variation was observed between choices made for the majority of input parameters, differing choices of Process Category ('PROC') code/activity descriptor and dustiness level impacted most on the resultant exposure estimates. Exposure estimates ranging over several orders of magnitude were generated for the same exposure situation by different tool users. Such unpredictable between-user variation will reduce consistency within REACH processes and could result in under-estimation or overestimation of exposure, risking worker ill-health or the implementation of unnecessary risk controls, respectively. Implementation of additional support and quality control systems for all tool users is needed to reduce between-assessor variation and so ensure both the protection of worker health and avoidance of unnecessary business risk management expenditure.

Airborne engineered nanomaterials in the workplace-a review of release and worker exposure during nanomaterial production and handling processes

For exposure and risk assessment in occupational settings involving engineered nanomaterials (ENMs), it is important to understand the mechanisms of release and how they are influenced by the ENM, the matrix material, and process characteristics. This review summarizes studies providing ENM release information in occupational settings, during different industrial activities and using various nanomaterials. It also assesses the contextual information - such as the amounts of materials handled, protective measures, and measurement strategies - to understand which release scenarios can result in exposure. High-energy processes such as synthesis, spraying, and machining were associated with the release of large numbers of predominantly small-sized particles. Low-energy processes, including laboratory handling, cleaning, and industrial bagging activities, usually resulted in slight or moderate releases of relatively large agglomerates. The present analysis suggests that process-based release potential can be ranked, thus helping to prioritize release assessments, which is useful for tiered exposure assessment approaches and for guiding the implementation of workplace safety strategies. The contextual information provided in the literature was often insufficient to directly link release to exposure. The studies that did allow an analysis suggested that significant worker exposure might mainly occur when engineering safeguards and personal protection strategies were not carried out as recommended.

An evaluation of on-tool shrouds for controlling respirable crystalline silica in restoration stone work

OBJECTIVES

The task of grinding sandstone with a 5-inch angle grinder is a major source of exposure to respirable crystalline silica (RCS), known to cause diseases such as silicosis and lung cancer among workers who work with these materials. A shroud may be a suitable engineering control for this task. The objectives of this study were to evaluate the effectiveness of four commercially available shrouds at reducing respirable dust and RCS levels during the task of grinding sandstone using tools and accessories typical of restoration stone work.

METHODS

The task of grinding sandstone with a 5-inch angle grinder, equipped with different grinding wheels, was carried out over three trials at a restoration stone masonry site. Photometric and RCS data were collected when a 5-inch grinder, equipped with different grinding wheels, was used to grind sandstone with and without a shroud. A total of 24 short duration samples were collected for each no shroud and with shroud combination. Worker feedback on the practicalities of each shroud evaluated was also collected.

RESULTS

Respirable dust concentrations and RCS were both significantly lower (P < 0.001) when the grinders were equipped with a shroud compared with grinders without a shroud. Total geometric mean (GM) photometric respirable dust levels measured when grinding with a shroud were 0.5 mg m(-3), a reduction of 92% compared to grinding without a shroud (7.1 mg m(-3)). The overall GM RCS concentrations were reduced by the use of a shroud by 99%. GM photometric exposure levels were highest when using the Hilti 5-inch diamond grinding cup and Diamond turbo cup and lowest when using the Corundum grinding point.

CONCLUSIONS

Concentrations of respirable dust and RCS can be significantly reduced by using commercially available shrouds while grinding sandstone with a 5-inch angle grinder in restoration stonework. The short-term photometric respirable dust and RCS measurements collected with and without a shroud indicate that dust and RCS concentrations are reduced by between 90 and 99%. Supplemental exposure controls such as respiratory protective equipment would be required to reduce worker 8-h time-weighted average RCS exposure to below the Scientific Committee on Occupational Exposure Limits recommended occupational exposure limit value of 0.05 mg m(-3) and the American Conference of Governmental Industrial Hygienists threshold limit value of 0.025 mg m(-3).

Determinants of respirable crystalline silica exposure among stoneworkers involved in stone restoration work

OBJECTIVES

Crystalline silica occurs as a significant component of many traditional materials used in restoration stonework, and stoneworkers who work with these materials are potentially exposed to stone dust containing respirable crystalline silica (RCS). Exposure to RCS can result in the development of a range of adverse health effects, including silicosis and lung cancer. An understanding of the determinants of RCS exposure is important for selecting appropriate exposure controls and in preventing occupational diseases. The objectives of this study were to quantify the RCS exposure of stoneworkers involved in the restoration and maintenance of heritage properties and to identify the main determinants of RCS exposure among this occupational group.

METHODS

An exposure assessment was carried out over a 3-year period amongst a group of stonemasons and stone cutters involved in the restoration and maintenance of heritage buildings in Ireland. Personal air samples (n = 103) with corresponding contextual information were collected. Exposure data were analysed using mixed-effects modelling to investigate determinants of RCS exposure and their contribution to the individual's mean exposure. Between-depot, between-worker, and within-worker variance components were also investigated.

RESULTS

The geometric mean (GM) RCS exposure concentrations for all tasks measured ranged from <0.02 to 0.70mg m(-3). GM RCS exposure concentrations for work involving limestone and lime mortar were <0.02-0.01mg m(-3), tasks involving granite were 0.01-0.06mg m(-3), and tasks involving sandstone were <0.02-0.70mg m(-3). Sixty-seven percent of the 8-h time-weighted average (TWA) exposure measurements for tasks involving sandstone exceeded the Scientific Committee on Occupational Exposure Limits recommended occupational exposure limit value of 0.05mg m(-3). Highest RCS exposure values were recorded for the tasks of grinding (GM = 0.70mg m(-3)) and cutting (GM = 0.70mg m(-3)) sandstone. In the mixed-effects analyses, task was found to be significantly associated with RCS exposure, with the tasks of grinding and cutting resulting in average exposures of between 32 and 70 times the exposures recorded for the task of stone decorating. The between-depot, between-worker, and within-worker variance components were reduced by 46, 89, and 49%, respectively, after including task in the mixed effects model.

CONCLUSIONS

Restoration stoneworkers are regularly overexposed (compared with 0.1 and 0.05mg m(-3) 8-h TWA) to RCS dust when working with sandstone. The results indicate that the tasks of cutting and grinding sandstone are predictors of increased exposure to RCS dust. In order to decrease exposure to RCS, efforts should be focused on developing and implementing interventions which focus on these high-risk tasks.

The future of exposure assessment: perspectives from the X2012 Conference

The British Occupational Hygiene Society, in collaboration with the Institute of Occupational Medicine, the University of Manchester, the UK Health and Safety Executive, and the University of Aberdeen hosted the 7th International Conference on the Science of Exposure Assessment (X2012) on 2 July-5 July 2012 in Edinburgh, UK. The conference ended with a special session at which invited speakers from government, industry, independent research institutes, and academia were asked to reflect on the conference and discuss what may now constitute the important highlights or drivers of future exposure assessment research. This article summarizes these discussions with respect to current and future technical and methodological developments. For the exposure science community to continue to have an impact in protecting public health, additional efforts need to be made to improve partnerships and cross-disciplinary collaborations, although it is equally important to ensure that the traditional occupational exposure themes are still covered as these issues are becoming increasingly important in the developing world. To facilitate this the 'X' conferences should continue to retain a holistic approach to occupational and non-occupational exposures and should actively pursue collaborations with other disciplines and professional organizations to increase the presence of consumer and environmental exposure scientists.

Application of a quantitative weight of evidence approach for ranking and prioritising occupational exposure scenarios for titanium dioxide and carbon nanomaterials

Substantial limitations and uncertainties hinder the exposure assessment of engineered nanomaterials (ENMs). The present deficit of reliable measurements and models will inevitably lead in the near term to qualitative and uncertain exposure estimations, which may fail to support adequate risk assessment and management. Therefore it is necessary to complement the current toolset with user-friendly methods for near-term nanosafety evaluation. This paper proposes an approach for relative exposure screening of ENMs. For the first time, an exposure model explicitly implements quantitative weight of evidence (WoE) methods and utilises expert judgement for filling data gaps in the available evidence-base. Application of the framework is illustrated for screening of exposure scenarios for nanoscale titanium dioxide, carbon nanotubes and fullerenes, but it is applicable to other nanomaterials as well. The results show that the WoE-based model overestimates exposure for scenarios where expert judgement was substantially used to fill data gaps, which suggests its conservative nature. In order to test how variations in input data influence the obtained results, probabilistic Monte Carlo sensitivity analysis was applied to demonstrate that the model performs in stable manner.

Aggregation of exposure level and probability into a single metric in job-exposure matrices creates bias

Job-exposure matrices (JEMs) are often used in occupational epidemiological studies to provide an exposure estimate for a typical person in a 'job' during a particular time period. A JEM can produce exposure estimates on a variety of scales, such as (but not limited to) binary assessments of presence or absence of exposure, ordinal ranking of exposure level and frequency, and quantitative exposure estimates of exposure intensity and frequency. Specifically, one popular approach to construct a JEM, engendered in a Finnish job exposure matrix (FINJEM), provides a probability that a worker within an occupational group is exposed and an estimate of intensity of exposure among the exposed workers within this occupation. Often the product of the probability and intensity (aka level) is used to obtain the estimate of exposure for the epidemiological analyses. This procedure aggregates exposure across exposed and non-exposed individuals and the effect of this particular procedure on epidemiological analyses has never been studied. We developed a theoretical framework for understanding how these aggregate exposure estimates relate to true exposure (either unexposed or log-normally distributed for 'exposed'), assuming that there is no uncertainty about estimates of level and probability of exposure. Theoretical derivations show that multiplying occupation-specific exposure level and probability of non-zero exposure results in both systematic and differential measurement errors. Simulations demonstrated that under certain conditions bias in odds ratios in a cohort study away from the null are possible and that this bias is smaller when (a) arithmetic rather than geometric mean is used to assess exposure level and (b) exposure level and prevalence are positively correlated. We illustrate the potential impact of using the specified JEM in a simulation based on a case-control study of non-Hodgkin lymphoma and exposure to ionizing and non-ionizing radiation. Inflation of standard errors in the log-odds was observed as well as bias away from null for two out of three specific exposures/data structures. Overall, it is clear that influence of the phenomenon we studied on epidemiological results is complex and difficult to predict, being influenced a great deal by the structure of data. We recommend exploring the influence of JEMs that use the product of exposure level and probability in epidemiological analyses through simulations during planning of such studies to assess both the expected extent of the potential bias in risk estimates and impact on power. The SAS and R code required to implement such simulations are provided. All our calculations are either theoretical or based on simulated data.

The relationship between inadvertent ingestion and dermal exposure pathways: a new integrated conceptual model and a database of dermal and oral transfer efficiencies

Occupational inadvertent ingestion exposure is ingestion exposure due to contact between the mouth and contaminated hands or objects. Although individuals are typically oblivious to their exposure by this route, it is a potentially significant source of occupational exposure for some substances. Due to the continual flux of saliva through the oral cavity and the non-specificity of biological monitoring to routes of exposure, direct measurement of exposure by the inadvertent ingestion route is challenging; predictive models may be required to assess exposure. The work described in this manuscript has been carried out as part of a project to develop a predictive model for estimating inadvertent ingestion exposure in the workplace. As inadvertent ingestion exposure mainly arises from hand-to-mouth contact, it is closely linked to dermal exposure. We present a new integrated conceptual model for dermal and inadvertent ingestion exposure that should help to increase our understanding of ingestion exposure and our ability to simultaneously estimate exposure by the dermal and ingestion routes. The conceptual model consists of eight compartments (source, air, surface contaminant layer, outer clothing contaminant layer, inner clothing contaminant layer, hands and arms layer, perioral layer, and oral cavity) and nine mass transport processes (emission, deposition, resuspension or evaporation, transfer, removal, redistribution, decontamination, penetration and/or permeation, and swallowing) that describe event-based movement of substances between compartments (e.g. emission, deposition, etc.). This conceptual model is intended to guide the development of predictive exposure models that estimate exposure from both the dermal and the inadvertent ingestion pathways. For exposure by these pathways the efficiency of transfer of materials between compartments (for example from surfaces to hands, or from hands to the mouth) are important determinants of exposure. A database of transfer efficiency data relevant for dermal and inadvertent ingestion exposure was developed, containing 534 empirically measured transfer efficiencies measured between 1980 and 2010 and reported in the peer-reviewed and grey literature. The majority of the reported transfer efficiencies (84%) relate to transfer between surfaces and hands, but the database also includes efficiencies for other transfer scenarios, including surface-to-glove, hand-to-mouth, and skin-to-skin. While the conceptual model can provide a framework for a predictive exposure assessment model, the database provides detailed information on transfer efficiencies between the various compartments. Together, the conceptual model and the database provide a basis for the development of a quantitative tool to estimate inadvertent ingestion exposure in the workplace.

The relationship between workers' self-reported changes in health and their attitudes towards a workplace intervention: lessons from smoke-free legislation across the UK hospitality industry

Background

The evaluation of smoke-free legislation (SFL) in the UK examined the impacts on exposure to second-hand smoke, workers’ attitudes and changes in respiratory health. Studies that investigate changes in the health of groups of people often use self-reported symptoms. Due to the subjective nature it is of interest to determine whether workers’ attitudes towards the change in their working conditions may be linked to the change in health they report.

Methods

Bar workers were recruited before the introduction of the SFL in Scotland and England with the aim of investigating their changes to health, attitudes and exposure as a result of the SFL. They were asked about their attitudes towards SFL and the presence of respiratory and sensory symptoms both before SFL and one year later. Here we examine the possibility of a relationship between initial attitudes and changes in reported symptoms, through the use of regression analyses.

Results

There was no difference in the initial attitudes towards SFL between those working in Scotland and England. Bar workers who were educated to a higher level tended to be more positive towards SFL. Attitude towards SFL was not found to be related to change in reported symptoms for bar workers in England (Respiratory, p = 0.755; Sensory, p = 0.910). In Scotland there was suggestion of a relationship with reporting of respiratory symptoms (p = 0.042), where those who were initially more negative to SFL experienced a greater improvement in self-reported health.

Conclusions

There was no evidence that workers who were more positive towards SFL reported greater improvements in respiratory and sensory symptoms. This may not be the case in all interventions and we recommend examining subjects’ attitudes towards the proposed intervention when evaluating possible health benefits using self-reported methods.

An assessment of dermal exposure to heavy fuel oil (HFO) in occupational settings

Heavy fuel oil (HFO) components are a group of heavy petroleum streams produced in oil refineries from crude oil. Due to its physicochemical properties, the dermal route is an important route of exposure. However, no information on dermal exposure levels for HFO has previously been published. A method for measuring dermal HFO levels was developed using wipe sampling and measuring phenanthrene and naphthalene as markers of HFO exposure. Measurement surveys were carried out in four different types of facilities: oil refineries, distribution terminals, energy providers, and an engine building and repair company. Dermal wipe samples were collected from different anatomical regions: neck, hands, and forearms. The frequency of tasks with potential for dermal HFO exposure was generally low at these facilities, with the exception of the distribution terminals and the engine building and repair site. The geometric mean (GM) dermal load on the hands was ∼0.1 μg cm(-2) for both left and right hand and 0.013 and 0.019 μg cm(-2) for the left and right forearm, respectively. With one exception, all results from the neck samples were below the limit of detection. The highest dermal loads for the hands and forearms were found in the engine building and repair facility (hands: GM = 1.6 μg cm(-2); forearms: GM = 0.41 μg cm(-2)). The tasks with the highest dermal loads were the maintenance (hands: GM = 1.7 μg cm(-2)) and cleaning tasks (hands: GM = 0.24 μg cm(-2)). Actual dermal loads were low when compared with workplace dermal exposure measurements reported by other researchers for similar scenarios with other substances. This may be explained by high compliance of gloves use by workers during HFO handling tasks and likely avoidance of contact with HFO due to its high viscosity and the requirement to keep HFO at elevated temperatures during storage, transport, and use.

Advanced Reach Tool (ART): development of the mechanistic model

This paper describes the development of the mechanistic model within a collaborative project, referred to as the Advanced REACH Tool (ART) project, to develop a tool to model inhalation exposure for workers sharing similar operational conditions across different industries and locations in Europe. The ART mechanistic model is based on a conceptual framework that adopts a source receptor approach, which describes the transport of a contaminant from the source to the receptor and defines seven independent principal modifying factors: substance emission potential, activity emission potential, localized controls, segregation, personal enclosure, surface contamination, and dispersion. ART currently differentiates between three different exposure types: vapours, mists, and dust (fumes, fibres, and gases are presently excluded). Various sources were used to assign numerical values to the multipliers to each modifying factor. The evidence used to underpin this assessment procedure was based on chemical and physical laws. In addition, empirical data obtained from literature were used. Where this was not possible, expert elicitation was applied for the assessment procedure. Multipliers for all modifying factors were peer reviewed by leading experts from industry, research institutes, and public authorities across the globe. In addition, several workshops with experts were organized to discuss the proposed exposure multipliers. The mechanistic model is a central part of the ART tool and with advancing knowledge on exposure, determinants will require updates and refinements on a continuous basis, such as the effect of worker behaviour on personal exposure, 'best practice' values that describe the maximum achievable effectiveness of control measures, the intrinsic emission potential of various solid objects (e.g. metal, glass, plastics, etc.), and extending the applicability domain to certain types of exposures (e.g. gas, fume, and fibre exposure).

Classification of occupational activities for assessment of inhalation exposure

There is a large variety of activities in workplaces that can lead to emission of substances. Coding systems based on determinants of emission have so far not been developed. In this paper, a system of Activity Classes and Activity Subclasses is proposed for categorizing activities involving chemical use. Activity Classes share their so-called 'emission generation mechanisms' and physical state of the product handled and the underlying determinants of emission. A number of (industrial) stakeholders actively participated in testing and fine-tuning the system. With the help of these stakeholders, it was found to be relatively easy to allocate a large number of activities to the Activity Classes and Activity Subclasses. The system facilitates a more structured classification of activities in exposure databases, a structured analysis of the analogy of exposure activities, and a transparent quantification of the activity emission potential in (new) exposure assessment models. The first use of the system is in the Advanced REACH Tool.

Conceptual model for assessment of inhalation exposure to manufactured nanoparticles

As workplace air measurements of manufactured nanoparticles are relatively expensive to conduct, models can be helpful for a first tier assessment of exposure. A conceptual model was developed to give a framework for such models. The basis for the model is an analysis of the fate and underlying mechanisms of nanoparticles emitted by a source during transport to a receptor. Four source domains are distinguished; that is, production, handling of bulk product, dispersion of ready-to-use nanoproducts, fracturing and abrasion of end products. These domains represent different generation mechanisms that determine particle emission characteristics; for example, emission rate, particle size distribution, and source location. During transport, homogeneous coagulation, scavenging, and surface deposition will determine the fate of the particles and cause changes in both particle size distributions and number concentrations. The degree of impact of these processes will be determined by a variety of factors including the concentration and size mode of the emitted nanoparticles and background aerosols, source to receptor distance, and ventilation characteristics. The second part of the paper focuses on to what extent the conceptual model could be fit into an existing mechanistic predictive model for ''conventional'' exposures. The model should be seen as a framework for characterization of exposure to (manufactured) nanoparticles and future exposure modeling.

Bias in the estimation of exposure effects with individual- or group-based exposure assessment

In this paper, we develop models of bias in estimates of exposure-disease associations for epidemiological studies that use group- and individual-based exposure assessments. In a study that uses a group-based exposure assessment, individuals are grouped according to shared attributes, such as job title or work area, and assigned an exposure score, usually the mean of some concentration measurements made on samples drawn from the group. We considered bias in the estimation of exposure effects in the context of both linear and logistic regression disease models, and the classical measurement error in the exposure model. To understand group-based exposure assessment, we introduced a quasi-Berkson error structure that can be justified with a moderate number of exposure measurements from each group. In the quasi-Berkson error structure, the true value is equal to the observed one plus error, and the error is not independent of the observed value. The bias in estimates with individual-based assessment depends on all variance components in the exposure model and is smaller when the between-group and between-subject variances are large. In group-based exposure assessment, group means can be assumed to be either fixed or random effects. Regardless of this assumption, the behavior of estimates is similar: the estimates of regression coefficients were less attenuated with a large sample size used to estimate group means, when between-subject variability was small and the spread between group means was large. However, if groups are considered to be random effects, bias is present, even with large number of measurements from each group. This does not occur when group effects are treated as fixed. We illustrate these models in analyses of the associations between exposure to magnetic fields and cancer mortality among electric utility workers and respiratory symptoms due to carbon black.

Trends in inhalation exposure--a review of the data in the published scientific literature

As part of a larger study aimed at identifying the long-term changes in inhalation exposure for selected hazardous substances in a number of industrial sectors within the UK, we have reviewed the published literature on temporal changes in inhalation exposure. Scientific papers and reports of interest were identified using standard literature review techniques. Most studies did not express the results as relative annual trends in exposure, and so where possible the data were reanalysed using regression methods to produce estimates of the average annual percentage change in concentration. In the majority of instances, there were significant reductions in exposure, with percentage yearly declines up to 32%. In many studies, information about changes in the working environment, process conditions or other factors that may have influenced the change in exposure over time was lacking. Factors commonly cited as being responsible for exposure reductions included the introduction of new standards and response to regulatory requirements as well as changes in production methods. A large number of exposure measurement datasets exist for many industrial sectors for most of the second half of the 20th century and this resource has allowed us to identify trends in occupational exposure. It is most important that longitudinal exposure data continue to be collected along with relevant contextual information to enable future changes to be adequately assessed.

Levels of second hand smoke in pubs and bars by deprivation and food-serving status: a cross-sectional study from North West England

BACKGROUND

The UK government proposed introducing partial smokefree legislation for England with exemptions for pubs and bars that do not prepare and serve food. We set out to test the hypothesis that pubs from more deprived areas and non food-serving pubs have higher levels of particulate air pollution.

METHODS

We conducted a cross sectional study in four mainly urban areas of the North West of England. We recruited a stratified random sample of 64 pubs divided into four groups based on whether their local population was affluent or deprived (using a UK area based deprivation measure), and whether or not they served food. The timing of air quality monitoring stratified to ensure similar distribution of monitoring by day of the week and time of evening between groups. We used a portable air quality monitor to collect fine particle (PM2.5) levels over a minimum of 30 minutes in areas where smoking was allowed,, and calculated mean time-time weighted average PM2.5 levels.

RESULTS

Mean PM2.5 was 285.5 microg/m3 (95% CI 212.7 to 358.3). Mean levels in the four groups were: affluent food-serving pubs (n = 16) 188.1 microg/m3 (95%CI 128.1 to 248.1); affluent non food-serving (n = 16) 186.8 microg/m3 (95%CI 118.9 to 254.3); deprived food-serving (n = 17) 399.4 microg/m3 (95%CI 177.7 to 621.2); and deprived non food-serving (n = 15) 365.7 microg/m3 (195.6 to 535.7). Levels were higher in pubs in deprived communities: mean 383.6 microg/m3 (95% CI 249.2 to 518.0) vs 187.4 microg/m3 (144.8 to 229.9); geometric mean 245.2 microg/m3 vs 151.2 microg/m3 (p = 0.03). There was little difference in particulate levels between food and non food-serving pubs.

CONCLUSION

This study adds to the evidence that the UK government's proposals for partial smokefree legislation in England would offer the least protection to the most heavily exposed group--bar workers and customers in non food-serving pubs in deprived areas. The results suggest these proposals would work against the UK government's stated aim to reduce health inequalities.

Are Variance Components of Exposure Heterogeneous Between Time Periods and Factories in the European Carbon Black Industry?

Occupational exposure to chemical agents can vary enormously within- and between-workers, even when carrying out the same jobs. When repeated measurements are available, the variance components can be estimated using random- or mixed-effects models. Pooling the variance components across the fixed effects, in mixed-effects models, reduces the complexity of the models; especially, when there are a large number of fixed effects. The analyses presented in this paper tested the assumptions of homogeneity in the variance components between factories and surveys for inhalable dust exposure in the European carbon black manufacturing industry. In total, 5296 measurements from 1771 workers were available collected during two surveys carried out between 1991 and 1995. Workers were grouped into eight job categories, and for each of these separate mixed-effects models were developed, including factory, survey and in some cases the interaction term as the fixed effects. The likelihood ratio test was used to test the assumptions of homogeneity of the variance components. Statistically significant heterogeneity of the variance components was observed for two of the eight job categories, 'Fitter/Welder' and 'Warehouseman'. The heterogeneity was due mainly to differences in variance between the factories. When estimating the probability of overexposure for all the factories combined, there was little difference between the models with and without heterogeneous variance components for 'Fitters/Welders'. For the 'Warehousemen' the probability of overexposure in the last survey changed marginally from 4% in the pooled model to 6% in the heterogeneous model. Larger differences between the models were observed when estimating the probability of overexposure for individual factories, which was due to over- or under-estimation of the variance components in the pooled models. In conclusion, for most job categories pooling of the variance components appears to be justified in this database. In addition, no large differences were found when determining the industry-wide probability of 'overexposure' when comparing the pooled with the heterogeneous models. However, when evaluating the factory-specific probability of 'overexposure' or when using the models to provide exposure estimates for epidemiological studies heterogeneity in the variance components should be investigated.

Commentary: variability in workplace exposures and the design of efficient measurement and control strategies

Kromhout et al.'s (1993) well-cited publication presented detailed information on statistical procedures to estimate the magnitude of exposure variability within and between workers, drawing from a large database on chemical exposures throughout industry. It convincingly demonstrated that the construct of homogeneous exposure groups often does not hold true and suggested ways to improve measurement strategies. The authors hit a rich vein of research, and many publications, not at least by the authors themselves, followed in the decade after publication. In recent years the principles of estimating the variation in exposure have been applied in new methods for optimization of sampling strategies, for compliance testing, for quantifying exposures in epidemiologic studies, and for identifying important sources of emissions and suggesting strategies for controlling exposures. Many occupational hygienists across the globe have adopted these new methods as powerful tools in their exposure assessment strategies.

A job-exposure matrix for potential endocrine-disrupting chemicals developed for a study into the association between maternal occupational exposure and hypospadias

A study to assess the association between the prevalence of hypospadias and maternal occupational exposure to potential endocrine-disrupting chemicals was carried out using data from the congenital anomaly register of the Office for National Statistics. The occupation of the mother is recorded in this register and to facilitate the assessment of maternal occupational exposure, a specific job-exposure matrix for potential endocrine-disrupting chemicals was developed. Seven categories of contaminants were evaluated (pesticides, polychlorinated organic compounds, phthalates, alkylphenolic compounds, bi-phenolic compounds, heavy metals and other substances). Maternal occupations were all coded using the 1980 version of Categories of Occupations. Three occupational hygienists assessed the likelihood of exposure (unlikely, possible, probable) to these seven substance groups for all 348 possible job titles independently. Almost 30% of the job titles were classified as exposed to at least one substance category (possible or probable), with approximately 16% of the job titles being probably exposed to at least one substance category. Some examples of occupations with probable exposure to potential endocrine-disrupting chemicals include: farm workers, electricians, workers in the plastics industry, painters, printers, hairdressers, dental practitioners, laboratory workers, textile workers and cleaners. It is recognized that there are a lot of limitations to the use of job-exposure matrices in general and with the matrix presented in this paper in particular. However, the matrix forms the basis on which further developments on occupational exposure assessment of potential endocrine-disrupting chemicals could be founded. In addition, the job-exposure matrix has identified areas where more exposure information is required. For example, exposure to potential endocrine-disrupting chemicals can occur in occupations such as hairdressing and workers in beauty salons, where the working population is more likely to be female and for which little data exist on levels of exposure.