Estimated daily intake and cumulative risk assessment of organophosphate esters and associations with DNA damage among e-waste workers in Hong Kong

Organophosphate esters (OPEs) are extensively used as additives in various products, including electronic equipment, which becomes e-waste when obsolete. Nevertheless, no study has evaluated OPEs exposure levels and the related health risks among e-waste workers in Hong Kong. Therefore, 201 first-spot morning urine samples were collected from 101 e-waste workers and 100 office workers to compare eight urinary OPE metabolites (mOPEs) levels in these groups. The concentrations of six mOPEs were similar in e-waste workers and office workers, except for significantly higher levels of diphenyl phosphate (DPHP) in e-waste workers and bis(1-chloro-2propyl) phosphate (BCIPP) in office workers. Spearman correlation analysis showed that most non-chlorinated mOPEs were correlated with each other in e-waste workers (i.e., nine out of ten pairs, including di-p-cresyl phosphate (DpCP) and di-o-cresyl phosphate (DoCP), DpCP and bis(2-butoxyethyl) phosphate (BBOEP), DpCP and DPHP, DpCP and dibutyl phosphate (DBP), DoCP and BBOEP, DoCP and DPHP, DoCP and DBP, BBOEP and DPHP, DPHP and DBP), indicating that handling e-waste could be the exposure source of specific OPEs. The median values of estimated daily intake (EDI) and hazard quotient (HQ) suggested that the health risks from OPEs exposures were under the recommended thresholds. However, linear regression models, Quantile g-computation, and Bayesian kernel machine regression found that urinary mOPEs elevated 8-hydroxy-2-deoxyguanosine (8-OhdG) levels individually or as a mixture, in which DPHP contributed prominently. In conclusion, although e-waste might not elevate the internal OPEs levels among the participating Hong Kong e-waste workers, attention should be paid to the potential DNA damage stimulated by OPEs under the currently recommended thresholds.

Risk of chronic obstructive pulmonary disease in a large cohort of Ontario, Canada workers

Although several occupational exposures have been linked to the risk of COPD; limited data exists on sex-specific differences. This study aimed to identify at-risk occupations and sex differences for COPD risk. Cases were identified in a large surveillance system established through the linkage of former compensation claimants' data (non-COPD claims) to physician visits, ambulatory care data, and hospital inpatient data (1983-2020). Cox proportional hazard models were used to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CI) for occupation groups (occupation at time of claim), stratified by sex. HRs were indirectly adjusted for cigarette smoking using another population dataset. A total of 29,445 male and 14,693 female incident cases of COPD were identified. Increased risks were observed in both sexes for construction (HRmale 1.15, 95% CI 1.12-1.19; HRfemale 1.54, 95% CI 1.29-1.83) transport/equipment operating (HRmale 1.32, 95% CI 1.28-1.37; HRfemale 1.53, 95% CI 1.40-1.68) farming (HRmale 1.23, 95% CI 1.15-1.32; HRfemale 1.19, 95% CI 1.04-1.37) and janitors/cleaners (HRmale 1.31, 95% CI 1.24-1.37; HRfemale 1.40, 95% CI 1.31-1.49). Increased risks were observed for females employed as chefs and cooks (HR 1.44, 95% CI 1.31-1.58), bartenders (HR 1.38, 95% CI 1.05-1.81), and those working in food/beverage preparation (HR 1.34, 95% CI 1.24-1.45) among other occupations. This study demonstrates elevated risk of COPD among both male and female workers potentially exposed to vapours, gases, dusts, and fumes, highlighting the need for occupational surveillance of COPD.

Assessing Neurobehavioral Alterations Among E-waste Recycling Workers in Hong Kong

Background

E-waste workers in Hong Kong are handling an unprecedented amount of e-waste, which contains various neurotoxic chemicals. However, no study has been conducted to evaluate the neurological health status of e-waste workers in Hong Kong. This study aimed to evaluate the prevalence of neurobehavioral alterations and to identify the vulnerable groups among Hong Kong e-waste workers.

Methods

We recruited 109 Hong Kong e-waste workers from June 2021 to September 2022. Participants completed standard questionnaires and wore a GENEActiv accelerometer for seven days. Pittsburgh Sleep Quality Index and Questionnaire 16/18 (Q16/18) were used to assess subjective neurobehavioral alterations. The GENEActiv data generated objective sleep and circadian rhythm variables. Workers were grouped based on job designation and entity type according to the presumed hazardous level. Unconditional logistic regression models measured the associations of occupational characteristics with neurobehavioral alterations after adjusting for confounders.

Results

While dismantlers/repairers and the workers in entities not funded by the government were more likely to suffer from neurotoxic symptoms in Q18 (adjusted odds ratio: 3.18 [1.18-9.39] and 2.77 [1.10-7.46], respectively), the workers from self-sustained recycling facilities also have poor performances in circadian rhythm. Results also showed that the dismantlers/repairers working in entities not funded by the government had the highest risk of neurotoxic symptoms compared to the lowest-risk group (i.e., workers in government-funded companies with other job designations).

Conclusion

This timely and valuable study emphasizes the importance of improving the working conditions for high-risk e-waste workers, especially the dismantlers or repairers working in facilities not funded by the government.

Artificial intelligence and the work-health interface: A research agenda for a technologically transforming world of work

The labor market is undergoing a rapid artificial intelligence (AI) revolution. There is currently limited empirical scholarship that focuses on how AI adoption affects employment opportunities and work environments in ways that shape worker health, safety, well-being and equity. In this article, we present an agenda to guide research examining the implications of AI on the intersection between work and health. To build the agenda, a full day meeting was organized and attended by 50 participants including researchers from diverse disciplines and applied stakeholders. Facilitated meeting discussions aimed to set research priorities related to workplace AI applications and its impact on the health of workers, including critical research questions, methodological approaches, data needs, and resource requirements. Discussions also aimed to identify groups of workers and working contexts that may benefit from AI adoption as well as those that may be disadvantaged by AI. Discussions were synthesized into four research agenda areas: (1) examining the impact of stronger AI on human workers; (2) advancing responsible and healthy AI; (3) informing AI policy for worker health, safety, well-being, and equitable employment; and (4) understanding and addressing worker and employer knowledge needs regarding AI applications. The agenda provides a roadmap for researchers to build a critical evidence base on the impact of AI on workers and workplaces, and will ensure that worker health, safety, well-being, and equity are at the forefront of workplace AI system design and adoption.

Silicosis, asbestosis, and pulmonary fibrosis in Ontario, Canada from 1996 to 2019

BACKGROUND

Silicosis is a fibrotic lung disease caused by exposure to respirable crystalline silica. Historically, silicosis was common among miners and other professions in the 20th century, and in recent decades has re-emerged in coal mining and appeared in new workplaces, including the manufacture of distressed jeans and artificial stone countertops.

METHODS

Physician billing data for the province of Ontario between 1992 and 2019 were analyzed across six time-periods (1993-1995, 1996-2000, 2001-2005, 2006-2010, 2011-2015, and 2016-2019). The case definition was two or more billing records within 24 months with a silicosis diagnosis code (ICD-9 502, ICD-10 J62). Cases from 1993 to 1995 were excluded as prevalent cases. Crude incidence rates per 100,000 persons were calculated by time-period, age, sex, and region. Analyses were repeated in parallel for pulmonary fibrosis (PF) (ICD-9 515, ICD-10 J84) and asbestosis (ICD-9 501; ICD-10 J61).

RESULTS

From 1996 to 2019, 444 cases of silicosis, 2719 cases of asbestosis and 59,228 cases of PF were identified. Silicosis rates decreased from 0.42 cases per 100,000 in 1996-2000 to 0.06 per 100,000 people in 2016-2019. A similar trend was observed for asbestosis (1.66 to 0.51 per 100,000 persons) but the incidence rate of PF increased from 11.6 to 33.9 per 100,000 persons. Incidence rates for all outcomes were higher among men and older adults.

CONCLUSIONS

A decreasing incidence of silicosis was observed in this analysis. However, the incidence of PF increased, consistent with findings from other jurisdictions. While cases of silicosis have been recorded among artificial stone workers in Ontario these cases do not seem to have impacted the population rates thus far. Ongoing, periodic surveillance of occupational diseases is helpful for tracking population-level trends over time.

Barriers and Facilitators in the Creation of a Surveillance System for Solar Radiation-Induced Skin Cancers

Outdoor workers are exposed to many hazards, including solar ultraviolet radiation (UVR). Identifying, reporting, analyzing and tracking the exposures or health outcomes of outdoor workers have not generally been formally considered. This article aims to summarize the best practices/strategies for creating an occupational sun exposure or skin cancer surveillance system for outdoor workers and to understand the key barriers and facilitators to the development of such a system. For the design of a successful occupational safety and health (OSH) surveillance system five occupational surveillance strategies are summarized: exposure registry, disease registry, disease screening/medical surveillance, sentinel event surveillance, and disease surveillance via data linkage. Ten key considerations are identified, including identifying a clear goal, a defined target population and stakeholder involvement, five critical barriers are highlighted including underreporting and funding, and five vital facilitators are recognized including communication/collaboration and a simple reporting process.

Tailored Sun Safety Messages for Outdoor Workers

Background

Messaging surrounding skin cancer prevention has previously focused on the general public and emphasized how or when activities should be undertaken to reduce solar ultraviolet radiation (UVR) exposure. Generic messages may not be applicable to all settings, and should be tailored to protect unique and/or highly susceptible subpopulations, such as outdoor workers. The primary objective of this study was to develop a set of tailored, practical, harm-reducing sun safety messages that will better support outdoor workers and their employers in reducing the risk of solar UVR exposure and UVR-related occupational illnesses.

Methods

We adapted a core set of sun safety messages previously developed for the general population to be more applicable and actionable by outdoor workers and their employers. This study used an integrated knowledge translation approach and a modified Delphi method (which uses a survey-based consensus process) to tailor the established set of sun safety messages for use for outdoor worker populations.

Results

The tailored messages were created with a consideration for what is feasible for outdoor workers, and provide users with key facts, recommendations, and tips related to preventing skin cancer, eye damage, and heat stress, specifically when working outdoors.

Conclusion

The resulting tailored messages are a set of evidence-based, expert- approved, and stakeholder-workshopped messages that can be used in a variety of work settings as part of an exposure control plan for employers with outdoor workers.

Radon exposure and risk of neurodegenerative diseases among male miners in Ontario, Canada: A cohort study

BACKGROUND

Environmental radon has been examined as a risk factor for neurodegenerative diseases in a small number of previous studies, but the findings have been inconsistent. This study aims to investigate the association between occupational radon exposure and neurodegenerative disease in a cohort of male miners with work experience in multiple ore types in Ontario, Canada.

METHODS

Radon exposure (1915-1988) was assessed using two job-exposure matrices (JEM) constructed from using historical records for 34,536 Ontario male miners. Neurodegenerative outcomes were ascertained between 1992 and 2018. Poisson regression models were used to estimate incidence rate ratios (RR) and 95% confidence intervals (CI) between cumulative radon exposure in working level months (WLM) and each neurodegenerative outcome.

RESULTS

Levels of cumulative radon exposure showed variability among cohort members with a mean of 7.5 WLM (standard deviation 24.4). Miners in uranium mines or underground jobs had higher levels and more variability in exposure than workers in non-uranium work or surface jobs. Compared to the reference group (radon < 1 WLM), increased rates of Alzheimer's (RR 1.23, 95% CI 1.05-1.45) and Parkinson's disease (RR 1.43, 95% CI 1.08-1.89) were observed among workers with >1-5 WLM and >5-10 WLM, respectively, but not among higher exposed workers (>10 WLM).

CONCLUSION

This study did not observe a positive monotonic dose-response relationship between cumulative radon exposure and Alzheimer's or Parkinson's disease in Ontario mining workers. There was no association observed with motor neuron disease.

Occupational Exposure of Canadian Nail Salon Workers to Plasticizers Including Phthalates and Organophosphate Esters

Personal exposure of nail salon workers to 10 phthalates and 19 organophosphate esters (OPEs) was assessed in 18 nail salons in Toronto, Canada. Active air samplers (n = 60) and silicone passive samplers, including brooches (n = 58) and wristbands (n = 60), were worn by 45 nail salon workers for ∼8 working hours. Diethyl phthalate (median = 471 ng m^-3) and diisobutyl phthalate (337 ng m^-3) were highest in active air samplers. Most abundant OPEs in active air samplers were tris(2-chloroisopropyl)phosphate or TCIPP (303 ng m^-3) and tris(2-chloroethyl)phosphate or TCEP (139 ng m^-3), which are used as flame retardants but have not been reported for use in personal care products or nail salon accessories. Air concentrations of phthalates and OPEs were not associated with the number of services performed during each worker's shift. Within a single work shift, a combined total of 16 (55%) phthalates and OPEs were detected on passive silicone brooches; 19 (66%) were detected on wristbands. Levels of tris(2-chloroisopropyl)phosphate, tris(1,3-dichloro-2-propyl)phosphate or TDCIPP, and triphenyl phosphate or TPhP wristbands were significantly higher than those worn by e-waste workers. Significant correlations (p < 0.05) were found between the levels of some phthalates and OPEs in silicone brooches and wristbands versus those in active air samplers. Stronger correlations were observed between active air samplers versus brooches than wristbands. Sampler characteristics, personal characteristics, and chemical emission sources are the three main factors proposed to influence the use of passive samplers for measuring semi-volatile organic compound exposure.

Potential risk factors associated with COVID-19 in health care workers

Background

Health care workers (HCWs) have been recognized as being at higher risk for coronavirus disease 2019 (COVID-19) infection; however, relevant factors and magnitude have not been clearly elucidated.

Aim

This study was aimed to describe COVID-19 infections among hospital employees at a large tertiary care hospital located in Ontario, Canada from March to July 2020, towards better understanding potential risk factors.

Methods

Data on all HCWs with either a positive COVID test or a high-risk exposure from March to July 2020 were analyzed. HCWs with positive COVID test results and high-risk exposures were described. Those who developed COVID-19 following high-risk exposure were compared to those who did not. Data were also analyzed to determine trends over time.

Results

Over the period of observation, 193 staff (2% of total working staff) had a positive COVID-19 test. Incidence of HCW infections closely followed community incidence. Overall, 31% of COVID-19 cases were deemed occupationally acquired. Of these, 41% were acquired from a patient, with the remainder (59%) from fellow staff. Over the same period, 204 staff were identified as having a high-risk exposure. The majority of exposures (55%) were patient-associated, with the remaining (45%) resulting from staff-to-staff contact. Overall, 13% went on to develop COVID-19. Of these cases, 58% were patient-associated and 42% were a result of staff-to-staff transmission.

Conclusions

HCWs are at risk for work-related COVID-19. Given the number of infections attributed to staff–staff transmission, greater attention could be paid to implementing prevention measures in non-clinical areas.

Aluminum dust exposure and risk of neurodegenerative diseases in a cohort of male miners in Ontario, Canada

OBJECTIVES

We estimated associations between respirable aluminum exposure through McIntyre Powder (MP), a fine-sized aluminum and aluminum compound powder, and neurological disease in a retrospective cohort of mining workers from Ontario, Canada. Outcomes included Alzheimer's disease, Alzheimer's with other dementias, Parkinson's disease, parkinsonism, and motor neuron disease.

METHODS

The cohort was created by linking a database of mining workers' work history to healthcare records. This analysis included 36 826 male miners potentially exposed to MP between 1943 and 1979, followed up for disease diagnosis between 1992 and 2018. Exposure was assessed using two approaches, self-reported and historical records. Neurological diseases were ascertained using physician billing and hospital discharge records. Poisson regression models were used to estimate associations between MP exposure and neurological outcomes using incidence rate ratios (RR) and 95% confidence intervals (95% CI).

RESULTS

Exposure to self-reported MP was associated with an elevated incidence rate of Parkinson's disease (RR 1.34, 95% CI 1.14-1.57). The rate of Parkinson's disease appeared to increase with the duration of exposure assessed by historical records. Having ever been exposed to MP was positively associated with an elevated rate of Alzheimer's with other dementias (RR 1.12, 95% CI 1.06-1.19) but not Alzheimer's disease alone.

CONCLUSION

This study found that miners who were exposed to MP (respirable aluminum) had elevated rates of Parkinson's disease. The rate of Parkinson's disease appeared to increase with the duration of exposure assessed by historical records.

Diesel Engine Exhaust Exposure in the Ontario Civil Infrastructure Construction Industry

OBJECTIVES

Diesel engine exhaust (DEE) is a known lung carcinogen and a common occupational exposure in Canada. The use of diesel-powered equipment in the construction industry is particularly widespread, but little is known about DEE exposures in this work setting. The objective of this study was to determine exposure levels and identify and characterize key determinants of DEE exposure at construction sites in Ontario.

METHODS

Elemental carbon (EC, a surrogate of DEE exposure) measurements were collected at seven civil infrastructure construction worksites and one trades training facility in Ontario using NIOSH method 5040. Full-shift personal air samples were collected using a constant-flow pump and SKC aluminium cyclone with quartz fibre filters in a 37-mm cassette. Exposures were compared with published health-based limits, including the Dutch Expert Committee on Occupational Safety (DECOS) limit (1.03 µg m-3 respirable EC) and the Finnish Institute of Occupational Health (FIOH) recommendation (5 µg m-3 respirable EC). Mixed-effects linear regression was used to identify determinants of EC exposure.

RESULTS

In total, 149 EC samples were collected, ranging from <0.25 to 52.58 µg m-3 with a geometric mean (GM) of 3.71 µg m-3 [geometric standard deviation (GSD) = 3.32]. Overall, 41.6% of samples exceeded the FIOH limit, mostly within underground worksites (93.5%), and 90.6% exceeded the DECOS limit. Underground workers (GM = 13.20 µg m-3, GSD = 1.83) had exposures approximately four times higher than below grade workers (GM = 3.56 µg m-3, GSD = 1.94) and nine times higher than above ground workers (GM = 1.49 µg m-3, GSD = 1.75). Training facility exposures were similar to above ground workers (GM = 1.86 µg m-3, GSD = 4.12); however, exposures were highly variable. Work setting and enclosed cabins were identified as the key determinants of exposure in the final model (adjusted R2 = 0.72, P < 0.001). The highest DEE exposures were observed in underground workplaces and when using unenclosed cabins.

CONCLUSIONS

This study provides data on current DEE exposure in Canadian construction workers. Most exposures were above recommended health-based limits, albeit in other jurisdictions, signifying a need to further reduce DEE levels in construction. These results can inform a hazard reduction strategy including targeted intervention/control measures to reduce DEE exposure and the burden of occupational lung cancer.

Estimating Historical Exposure to Respirable Crystalline Silica in the Mining Industry in Ontario, Canada Using a Newly Developed Exposure Database

OBJECTIVES

To use the recently developed Ontario Mining Exposure Database (OMED) to describe historical silica exposure in the Ontario metal mining industry and identify predictors of historical silica exposure.

METHODS

Personal respirable crystalline silica (RCS) data for metal mines were extracted from OMED and included both individual and summary measures, where multiple exposure measurements (n > 1) were aggregated and entered as a single exposure value (n = 1). Data were stratified by sample location (underground/surface) for analysis. Monte Carlo simulation was used to simulate individual measures from the summary measures. A fixed effects multiple linear regression model was used to assess the effects of commodity (ore mined), sample year, source of exposure data, and occupational group on RCS concentration. Parameter estimates (β), standard errors, and 95% upper and lower confidence intervals were reported.

RESULTS

The OMED contained 12 995 silica measurements. After limiting to RCS measurements in metal mines, and measures with sufficient information for analysis, 2883 RCS measurements collected from 1974 to 1991 remained, including 2816 individual and 67 summary measurements. In total, 321 individual RCS measurements were simulated from the 67 summary measures. The analysis database contained 2771 (12% simulated) underground measurements and 366 surface measurements (0% simulated). In the underground group, an overall geometric mean (GM) of 0.05 [geometric standard deviation (GSD) 3.09] mg m-3 was estimated with a 6% annual decrease over time. In this group, the commodity with the highest average RCS level was zinc mines (GM = 0.07 mg m-3) and the lowest was iron mines (GM = 0.01 mg m-3). In the surface group, an overall GM of 0.05 (GSD 3.70) mg m-3 was estimated with an 8% decreased over time. In this group, the commodity with the highest average RCS level was gold mines (GM = 0.07 mg m-3) and the lowest was zinc mines (GM = 0.03 mg m-3). In both groups, company collected data had lower estimated RCS compared with regulator collected data.

CONCLUSIONS

Historical RCS levels decreased over time. Mean measurements exceeded the American Conference of Governmental Industrial Hygienists current health-based threshold limit value (0.025 mg m-3). The main predictors of exposure were commodity, source of exposure data, and sample year. However, low R2 and high GSD values suggest additional predictors of RCS exposures in Ontario's metal mines exist that were unavailable in OMED.

Skin Exposure to Acrylates in Nail Salons

OBJECTIVES

The nail salon industry has seen significant growth in recent years. Nail technicians provide manicures, pedicures and apply artificial nails; tasks that expose them to chemicals, including acrylates that are known skin and respiratory sensitizers. This paper reports on potential skin exposure to acrylates among nail technicians in Toronto, Canada.

METHODS

Hand skin wipes were collected after (i) the application of artificial nails, (ii) the application of ultraviolet cured gel nail polish, and (iii) deliberate contact with nail polish. Surface wipes were collected from work areas and surfaces contaminated with known products. Wipe samples were analysed for eight acrylates: methyl acrylate (MA), ethyl acrylate (EA), methyl methacrylate (MMA), ethyl methacrylate (EMA), 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), 2-hydroxypropyl methacrylate (HPMA), and ethylene glycol dimethacrylate (EGDMA) by gas chromatography with mass spectrometry.

RESULTS

Thirty-five wipe samples were collected. No acrylates were detected in skin samples (n = 8) or work surfaces (n = 6). However, MMA, EMA, EA, HEMA, and HPMA were detected in the samples of surfaces contaminated with known products. MMA was detected in 28% of products tested. HEMA and HPMA were detected where deliberate contact with nail polish occurred.

CONCLUSIONS

These results confirm that acrylates are present in nail products. However, no acrylates were detected in skin wipes. MMA, a chemical prohibited for use in cosmetics in Canada, was detected in nail polishes. Nail technicians should continue to employ safe work practices that reduce the probability of skin contact with acrylates and other chemicals.

A Qualitative Study to Identify Characteristics of a Desirable Training Program for Prevention of Occupational Skin Disease

BACKGROUND

Training and education may be effective strategies for the prevention of work-related contact dermatitis. While there is some information in the literature related to skin-specific training experiences, there is very little information available on workers' preferences related to content and format and to barriers and facilitators to training.

OBJECTIVES

To understand workers' experiences and preferences for workplace training and barriers and facilitators to training.

METHODS

Following ethics approval, 24 patients with work-related contact dermatitis participated in semi-structured interviews obtaining information on training experiences, perceived training effectiveness, desired training characteristics, and barriers and facilitators to training. An inductive thematic analysis was used to identify themes.

RESULTS

Though many workers had received general workplace health and safety training, none reported training about skin exposure and disease prevention. Examples of what the workers perceived as good training included first aid training, while Workplace Hazardous Materials Information System training was felt to be ineffective. Desired content of training for preventing skin exposures included information on the hazards, short- and long-term health impacts, and potential symptoms and personal protective equipment. They desired multi-modal presentation (e.g. in-person and online supplement), hands-on training with visual content and suggested the use of personal stories and negative messaging. Training that could be applied outside the workplace was also valued. Barriers and facilitators to implementation included factors related to the training program itself, the organization, and the regulatory landscape.

CONCLUSIONS

These findings can help to shape more effective workplace training programs for skin protection.

Health and Safety in Nail Salons: A Cross-Sectional Survey

OBJECTIVES

In recent years, nail salons have become more abundant than ever. The majority are small businesses, often employing immigrant women. Nail technicians have many exposures at work including chemical, biological, physical, and ergonomic hazards but few data exist on their symptoms or occupational health and safety practices, particularly in the Canadian context. The aim of this study was to learn about nail technicians, their work, and their health and safety practices.

METHODS

Nail technicians were recruited from nail salons in Toronto, Ontario. Participants completed an anonymous survey with questions about demographics, work tasks, workplace health and safety practices, and symptoms (skin, respiratory, and musculoskeletal).

RESULTS

A total of 155 nail technicians (95% female) participated in the survey. The majority of nail technicians performed manicures (99%) and pedicures (96%) and applied shellac polishes (86%). Only a third (34%) applied acrylic artificial nails. The reported use of personal protective equipment (PPE) was very high; 88% reported using a mask at work and 96% reporting using gloves. The most common symptoms reported by technicians were neck (44%) and back pain (38%). Skin and respiratory symptoms were less common with 6% of technicians reporting cough, 8% wheeze, and 5% a current rash. Technicians working over 30 h per week reported more neck pain (52 vs. 32%, P = 0.02). Technicians who reported using shellac polishes were more likely to report a runny nose (25 vs. 0%, P = 0.01).

CONCLUSIONS

Nail technicians in Toronto, Canada are experiencing work-related symptoms. Musculoskeletal symptoms were the most common symptoms reported. Much of the focus on nail salons and health has been on chemical exposures, but ergonomic hazards should not be overlooked. Efforts to increase knowledge and improve occupational health in nail salons should include information on multiple possible workplace hazards and how to reduce impacts of exposure.

Sun Protection Use at Work and Leisure by Outdoor Workers in Alberta, Canada

OBJECTIVE

To assess the prevalence and determinants of sun protection behaviours among outdoors workers at work and leisure in Alberta, Canada.

METHODS

We collected outdoor workers' demographics, skin cancer risk factors, job information, and sun habits at work and leisure using self-completed questionnaires. For both settings, we compared use of specific behaviours and modelled determinants of sun protection behaviour scores.

RESULTS

At work, wearing a sleeved shirt (81% often/always) and hat (73%) were most prevalent, while seeking shade (12%) and applying sunscreen (36%) were least prevalent. Workers had higher sun protection scores at work than leisure. Hours spent outdoors was a strong determinant for both models. Additional leisure model predictors were eye colour, sex, skin type, and job group.

CONCLUSIONS

Differences in behaviours across settings were observed and should be considered when developing solar UVR exposure reduction initiatives.

Can Silicone Passive Samplers be Used for Measuring Exposure of e-Waste Workers to Flame Retardants?

Silicone passive samplers were assessed for measuring personal exposure to 37 flame retardants at three Québec e-waste recycling facilities. Silicone brooches (n = 45), wristbands (n = 28), and armbands (n = 9) worn during a ∼8 h work shift accumulated detectable amounts of 95-100% of the target compounds. Brooch concentrations were significantly correlated with those from active air samplers from which we conclude that the brooches could be used to approximate inhalation exposure and other exposures related to air concentrations such as dermal exposure. The generic sampling rate of the brooch (19 ± 11 m³ day^-1 dm^-2) was 13 and 22 times greater than estimated for home and office environments, respectively, likely because of the dusty work environment and greater movement of e-waste workers. BDE-209 concentrations in brooches and wristbands were moderately and significantly (p < 0.05) correlated with levels in blood plasma; organophosphorus esters in brooches and wristbands were weakly and insignificantly correlated with their metabolite biomarkers in post-shift spot urine samples. Silicone brooches and wristbands deployed over a single shift in a dusty occupational setting can be useful for indicating the internal exposure to compounds with relatively long biological half-lives, but their use for compounds with relatively short half-lives is not clear and may require either a longer deployment time or an integrated biomarker measure.

Neurodegenerative diseases among miners in Ontario, Canada, using a linked cohort

OBJECTIVES

We examined employment in mining occupations and industries and its association with neurological disease incidence in a linkage cohort from Ontario, Canada. Outcomes included Alzheimer's disease (alone and with other dementias), Parkinson's disease, parkinsonism, motor neuron disease and amyotrophic lateral sclerosis (ALS).

METHODS

The Occupational Disease Surveillance System cohort was created by linking workers' compensation data and healthcare usage records. This analysis included over 1.1 million male workers, followed between 1999 and 2016. Neurological diseases were ascertained using physician billing and hospital discharge records. Adjusted Poisson regression models were used to estimate incidence rate ratios (RR) comparing mining to non-mining workers overall and by ore (industry) and occupation group.

RESULTS

Suggested elevations in incidence rates were observed for ALS among workers of metal mines (RR 2.21, 95% CI 1.04 to 4.69) and for motor neuron disease among those employed in mining occupations within metal mining industries (RR 1.96, 95% CI 1.01 to 3.79), though these were based on relatively few cases. In miscellaneous metal mines, workers who held mining occupations had an elevated rate of Alzheimer's disease (RR 1.27, 95% CI 0.92 to 1.77). Parkinson's disease rate was elevated among workers with rock and soil drilling occupations (RR 1.60, 95% CI 1.04 to 2.45).

CONCLUSIONS

Mining hazards may be associated with elevated rates of neurodegenerative diseases among workers in mining occupations and industries. More work is needed to better understand mining exposures and their associations with neurodegenerative diseases.

Solar ultraviolet radiation exposure among outdoor workers in Alberta, Canada

BACKGROUND

Outdoor workers are at risk of prolonged and high solar ultraviolet radiation (UVR) exposure, which is known to cause skin cancer. The objectives of this study were to characterize the UVR exposure levels of outdoor workers in Alberta, Canada, and to investigate what factors may contribute to their exposure.

METHODS

This study collected objective solar UVR measurements from outdoor workers primarily in Alberta during the summer of 2019. Workers were recruited via the management or health and safety teams from building trade unions and employers. Calibrated, electronic UVR dosimeters were worn by workers on their hardhats, wrists, or lapels for five working days. Data on workers' demographics, jobs, sun protection behaviors, and personal risk factors were collected using questionnaires, and meteorological data for each sampling day were noted. Mean daily exposure measured as the standard erythemal dose (SED) was calculated and compared to the international occupational exposure limit guideline (1.3 SED). Marginal models were developed to evaluate potential determinants of occupational solar UVR exposure.

RESULTS

In total, 883 measurements were collected from 179 workers. On average, workerswere exposed to 1.93 SED (range: 0.03-16.63 SED) per day. Just under half of workers (45%) were exposed to levels exceeding the international exposure limit guideline. In the bivariate analyses, landscape and maintenance workers, as well as trade and recreation workers, had the highest levels of exposure (average: 2.64 and 1.84 SED, respectively). Regional variations were observed, with the "other" cities/regions (outside of Edmonton and Calgary) experiencing the highest average levels (2.60 SED). Workers who placed the dosimeters on their hardhats experienced higher levels compared to the other groups. Exposure was highest on sunny and mixed days. Education, trade, city, dosimeter placement, forecast, hair colour, and number of hours outside were included in the final exposure model, of which trade, dosimeter placement, forecast, and number of hours outside at work were statistically significant.

CONCLUSIONS

Exposure to elevated solar UVR levels is common among outdoor workers in Alberta. The study findings can help inform future monitoring studies and exposure reduction initiatives aimed at protecting workers.

A scoping review to identify strategies that work to prevent four important occupational diseases

BACKGROUND

Despite being largely preventable, many occupational diseases continue to be highly prevalent and extremely costly. Effective strategies are required to reduce their human, economic, and social impacts.

METHODS

To better understand which approaches are most likely to lead to progress in preventing noise-related hearing loss, occupational contact dermatitis, occupational cancers, and occupational asthma, we undertook a scoping review and consulted with a number of key informants.

RESULTS

We examined a total of 404 articles and found that various types of interventions are reported to contribute to occupational disease prevention but each has its limitations and each is often insufficient on its own. Our principal findings included: legislation and regulations can be an effective means of primary prevention, but their impact depends on both the nature of the regulations and the degree of enforcement; measures across the hierarchy of controls can reduce the risk of some of these diseases and reduce exposures; monitoring, surveillance, and screening are effective prevention tools and for evaluating the impact of legislative/policy change; the effect of education and training is context-dependent and influenced by the manner of delivery; and, multifaceted interventions are often more effective than ones consisting of a single activity.

CONCLUSIONS

This scoping review identifies occupational disease prevention strategies worthy of further exploration by decisionmakers and stakeholders and of future systematic evaluation by researchers. It also identified important gaps, including a lack of studies of precarious workers and the need for more studies that rigorously evaluate the effectiveness of interventions.

Estimating the burden of lung cancer in Canada attributed to occupational radon exposure using a novel exposure assessment method

Objective

Exposure to radon causes lung cancer. The scope and impact of exposure among Canadian workers have not been assessed. Our study estimated occupational radon exposure in Canada and its associated lung cancer burden.

Methods

Exposed workers were identified among the working population during the risk exposure period (1961–2001) using data from the Canadian Census and Labour Force Survey. Exposure levels were assigned based on 12,865 workplace radon measurements for indoor workers and assumed to be 1800 mg/m³ for underground workers. Lung cancer risks were calculated using the Biological Effects of Ionizing Radiation (BEIR) VI exposure-age-concentration model. Population attributable fractions were calculated with Levin’s equation and applied to 2011 Canadian lung cancer statistics.

Results

Approximately 15.5 million Canadian workers were exposed to radon during the risk exposure period. 79% of exposed workers were exposed to radon levels < 50 Bq/m³ and 4.8% were exposed to levels > 150 Bq/m³. We estimated that 0.8% of lung cancers in Canada were attributable to occupational radon exposure, corresponding to approximately 188 incident lung cancers in 2011.

Conclusions

The lung cancer burden associated with occupational radon exposure in Canada is small, with the greatest burden occurring among those exposed to low levels of radon.

Silicone wristbands integrate dermal and inhalation exposures to semi-volatile organic compounds (SVOCs)

Silicone wristbands are being increasingly used to assess human exposure to semi-volatile organic compounds (SVOCs). However, it is unclear what exposure pathways wristbands integrate. To test the hypothesis that wristbands integrate inhalation and dermal exposures, we measured 38 chemicals from four compound groups (PAHs, PBDEs, nBFRs, and OPEs) in silicone wristbands and brooches, active air samples (Occupational Safety and Health Administration Versatile Sampler or OVS cartridge), and hand wipes from 10 adults during a 72-hour period. Phenanthrene, BDE-47, 2‑ethylhexyl 2,3,4,5‑tetrabromobenzoate (EHTBB), tris[(2R)‑1‑chloro‑2‑propyl] phosphate (TCIPP), and tris(1,3‑dichloro‑2‑propyl) phosphate (TDCIPP) were the predominant compounds in all four matrices. In a linear regression analysis, the compound levels in OVS were positively associated with those in wristbands and brooches for nBFRs and OPEs, but not for PAHs and PBDEs. The compound levels in wristbands were positively associated with those in hand wipes and brooches for all chemicals. The regressions between the levels in wristbands and OVS or brooches combined with the levels in hand wipes showed stronger, supporting the hypothesis that wristbands captured inhalation and dermal exposure pathways.

Urinary bisphenol A and incidence of metabolic syndrome among Chinese men: a prospective cohort study from 2013 to 2017

OBJECTIVES

Experimental studies suggested that bisphenol A (BPA) exposure increased the risk of metabolic syndrome (MetS) through the mechanism of insulin resistance. All previous epidemiological studies of BPA and MetS were cross-sectional studies, and their findings were mixed. This study aims to provide further evidence on the association between urinary BPA and risk of MetS using a prospective cohort study in China.

METHODS

The study population was from the Shenzhen Night shift workers' cohort. A total of 1227 male workers were recruited from the baseline survey in 2013 and then followed until 2017. Modified Adult Treatment Panel III criteria were used to identify the cases of MetS. Urinary BPA concentration was assessed using high-performance liquid chromatography-tandem mass spectrometry, and it was categorised into three subgroups by tertiles to obtain the adjusted HR (aHR) and 95% CI using Cox proportional hazard model.

RESULTS

During 4 years of follow-up, 200 subjects developed MetS. Compared with the lowest urinary BPA subgroup, a weakly increased risk of MetS was suggested among those with the middle (aHR=1.19, 95% CI 0.87 to 1.63) and high level of urinary BPA (aHR=1.16, 95% CI 0.84 to 1.59); however, the significant association with MetS was restricted primarily to the smokers, showing a positive gradient with urinary BPA (middle level: aHR=2.40, 95% CI 1.13 to 5.08; high level: aHR=2.87, 95% CI 1.38 to 5.98; p trend= 0.010).

CONCLUSION

This prospective cohort study provided further evidence that exposure to BPA may increase the risk of MetS, and this association was further positively modified by cigarette smoking.

The impact of night shift work on breast cancer: Results from the Burden of Occupational Cancer in Canada Study

BACKGROUND

We estimated the proportion and number of female breast cancer cases in Canada attributable to night shift work, a probable cause of breast cancer.

METHODS

Levin's equation was used to calculate population attributable fractions (PAFs) among Canadian women who ever worked night/rotating shifts from 1961 to 2000, accounting for labor turnover and survival to the year 2011. The calculated PAFs were applied to 2011 Canadian breast cancer incidence statistics to obtain the number of attributable cases.

RESULTS

Approximately 1.5 million women ever worked night/rotating shifts during 1961-2000 and survived to 2011. The PAFs ranged from 2.0% (95% confidence interval [CI]: 1.4-6.2) to 5.2% (95% CI: 3.7-13.6), and 470 to 1200 incident breast cancer cases in 2011 were likely due to shift work, of which 38% would have been diagnosed among women in health-related occupations.

CONCLUSIONS

More research is needed to increase the certainty of this association, but current evidence supports workplace-based prevention.

Exposure of Canadian electronic waste dismantlers to flame retardants

Exposure of e-waste workers to eight halogenated and five organophosphate ester flame retardant chemicals (FRs) was studied at a Canadian e-waste dismantling facility. FR concentrations were measured in air and dust samples collected at a central location and at four work benches over five-24 hour periods spanning two weeks. The highest concentrations in air from workbenches were of BDE-209 (median 156 ng m^-3), followed by Tris(2-chloroethyl) phosphate (TCEP, median 59 ng m^-3). Dust concentrations at the workbenches were higher than those measured at the central location, consistent with the release of contaminated dust during dismantling. Dust concentrations from the workbenches were also dominated by BDE-209 (median 96,300 ng g^-1), followed by Triphenyl phosphate (TPhP, median 47,000 ng g^-1). Most FRs were in coarse particles 5.6-18 μm diameter and ~30% were in respirable particles (<~3 μm). Exposure estimates indicated that dust ingestion accounted for 63% of total FR exposure; inhalation and dermal absorption contributed 35 and 2%, respectively. Some air and dust concentrations as well as some estimated exposures in this formal facility in a high-income country exceeded those from informal e-waste facilities located in low and middle income countries. Although there is demonstrated toxicity of some FRs, FR exposure in the e-waste industry has received minimal attention and occupational limits do not exist for most FRs.

The current burden of cancer attributable to occupational exposures in Canada

Exposure to occupational carcinogens is often overlooked as a contributor to the burden of cancer. To estimate the proportion of cancer cases attributable to occupational exposure in Canada in 2011, exposure prevalence and levels of 44 carcinogens were informed by data from the Canadian carcinogen exposure surveillance project (CAREX Canada). These were used with Canadian Census (between 1961 and 2011) and Labour Force Survey (annual surveys between 1976 and 2013) data to estimate the number of workers ever exposed to occupational carcinogens. Risk estimates of the association between each carcinogen and cancer site were selected mainly from published literature reviews. Population attributable risks were estimated using Levin's equation and applied to the 2011 cancer statistics from the Canadian Cancer Registry. It is estimated that 15.5 million Canadians alive in 2011 were exposed, during at least one year between 1961 and 2001, to at least one carcinogen in the workplace. Overall, we estimated that in 2011, between 3.9% (95% CI: 3.1%-8.1%) and 4.2% (95% CI: 3.3%-8.7%) of all incident cases of cancer were due to occupational exposure, corresponding to lower and upper numbers of 7700-21,800 cases. Five of the cancer sites - mesothelioma, non-melanoma skin cancer, lung, female breast, and urinary bladder - account for a total of 7600 to 21,200 cancers attributable to occupational exposures such as solar radiation, asbestos, diesel engine exhaust, crystalline silica, and night shift work. Our study highlights cancer sites and occupational exposures that need recognition and efforts by all stakeholders to avoid preventable cancers in the future.

Using health insurance administrative data to explore patch testing utilization in Ontario, Canada-An untapped resource

BACKGROUND

Patch testing is the key diagnostic test for diagnosing allergic contact dermatitis, but there is limited information on the use of patch testing at the population level.

OBJECTIVES

To utilize Ontario Health Insurance Plan (OHIP) data to analyse trends in the rate of patch testing in Ontario.

METHODS

Patch testing billing data submitted to the OHIP between 1992 and 2014 were analysed. Two patch test billing codes were investigated: one for work-related testing (G198), and one for non-work-related testing (G206). Rates of patch testing overall were calculated, and trends over time were described.

RESULTS

There were 51 576 patch test billings: 48 416 non-work-related and 3160 work-related. The annual rate of non-work-related patch testing (G206) ranged from 11.9 per 100 000 people to 25.9 per 100 000 people, increasing over time. The rate of work-related patch testing (G198) ranged from 0.17 to 2.32 per 1 000 000 people, and was relatively stable. The overall distribution of billing by specialty was 70% dermatology, 19% other medical subspecialties, and 10% paediatrics and family medicine.

CONCLUSIONS

Administrative health data can contribute to a more complete understanding of patch test utilization at the population level and, over time, can be used to track patch testing practices.

Polydimethylsiloxane (silicone rubber) brooch as a personal passive air sampler for semi-volatile organic compounds

Exposure assessments conducted using a personal sampler include the contribution of human activities to exposure that is neglected when using a stationary air sampler. This study evaluated the uptake characteristics and application of the polydimethylsiloxane (PDMS or silicone rubber) brooch as a personal passive air sampler (PPAS) for measuring concentrations of two groups of semi-volatile organic compounds (SVOCs), namely phthalates and organophosphate esters (OPEs), indoors in proximity to the breathing zone. Uptake rates of the PDMS brooch were calibrated against a personal low volume active air sampler (PLV-AAS) co-deployed on each of five study participants working in offices for 8 hs daily for four days. Sampling rates measured here ranged from 0.41 ± 0.33 to 1.33 ± 0.34 m³ day^-1 dm^-2 with an average value of 0.86 ± 0.29 m³ day^-1 dm^-2. Personal air concentrations of 1211 to 2640 ng m^-3 for ∑₅ phthalates and 254 to 663 ng m^-3 for ∑₅ OPEs were measured for three study participants who used the PDMS brooches continuously for seven days. These concentrations resulted in estimated inhalation exposures of 19,400 to 42,400 ng day^-1 for ∑₅ phthalates and 4,070 to 10,600 ng day^-1 for ∑₅ OPEs. This study demonstrated that the PDMS brooch can be used to assess inhalation exposure when worn for at least 24 h indoors, for compounds present in >4 ng m^-3 in air such as individual phthalates and OPEs tested here.

Examining lung cancer risks across different industries and occupations in Ontario, Canada: the establishment of the Occupational Disease Surveillance System

Background

The Occupational Disease Surveillance System (ODSS) was established in Ontario, Canada by linking a cohort of workers with data created from Workplace Safety and Insurance Board (WSIB) claims to administrative health databases. The aim of this study was to use ODSS to identify high-risk industry and occupation groups for lung cancer in Ontario.

Methods

Workers in the WSIB lost time claims database were linked to the Ontario Cancer Registry using subjects’ health insurance numbers, name, sex, birthdate and death date (if applicable). Several occupations and industries known to be at increased risk were outlined a priori to examine whether ODSS could replicate these associations. Age-adjusted, sex-stratified Cox proportional hazard models compared the risk of lung cancer within one industry/occupation versus all other groups in the cohort. Workers with a lung cancer diagnosis prior to cohort entry were excluded for analysis, leaving 2 187 762 workers for analysis.

Results

During the 1983 to 2014 follow-up, 34 661 workers in the cohort were diagnosed with lung cancer. Among expected high-risk industries, elevated risks were observed among workers in quarries/sand pits and construction industries for both sexes, and among males in metal mines, iron foundries, non-metallic mineral products industries and transportation industries. Excess risk was also observed among occupations in drilling/blasting, other mining/quarrying, mineral ore treating, excavating/grading/paving, truck driving, painting, bus driving and construction.

Conclusions

This current surveillance system identified several established high-risk groups for lung cancer and could be used for ongoing surveillance of occupational lung cancer in Ontario.

Burden of lung cancer attributable to occupational diesel engine exhaust exposure in Canada

Objective

To estimate the population attributable fraction (PAF) and number of incident and fatal lung cancers in Canada from occupational exposure to diesel engine exhaust (DEE).

Methods

DEE exposure prevalence and level estimates were used with Canadian Census and Labour Force Survey data to model the exposed population across the risk exposure period (REP, 1961–2001). Relative risks of lung cancer were calculated based on a meta-regression selected from the literature. PAFs were calculated using Levin’s equation and applied to the 2011 lung cancer statistics obtained from the Canadian Cancer Registry.

Results

We estimated that 2.4% (95% CI 1.6% to 6.6%) of lung cancers in Canada are attributable to occupational DEE exposure, corresponding to approximately 560 (95% CI 380 to 1570) incident and 460 (95% CI 310 to 1270) fatal lung cancers in 2011. Overall, 1.6 million individuals alive in 2011 were occupationally exposed to DEE during the REP, 97% of whom were male. Occupations with the highest burden were underground miners, truck drivers and mechanics. Half of the attributable lung cancers occurred among workers with low exposure.

Conclusions

This is the first study to quantify the burden of lung cancer attributable to occupational DEE exposure in Canada. Our results underscore a large potential for prevention, and a large public health impact from occupational exposure to low levels of DEE.

Silica exposure in a mining exploration operation

BACKGROUND

Though there is extensive research on occupational exposure in production mines, there is limited information on exposure during the exploration phase of mining.

METHODS

Air samples were collected in a core processing facility in Northern Ontario, Canada. All samples were analyzed for respirable dust (NIOSH 0600) and respirable crystalline silica (NIOSH 7602). Mean exposure levels were estimated and differences in exposure between work areas were investigated.

RESULTS

Sixteen personal and nine area air samples were collected. Respirable dust exposure ranged from < LOD to 2.24mg-m^-3; respirable silica exposure ranged from < LOD to 0.055mg-m^-3. Silica concentrations were higher among workers in the core cutting and core sorting (pulp and reject) areas, as compared to those in the core logging area.

CONCLUSIONS

Workers employed in core processing facilities as part of mining exploration activities are exposed to respirable silica; exposure controls may be needed.

Historical occupational isocyanate exposure levels in two Canadian provinces

Isocyanates such as toluene 2, 4-diisocyanate (TDI), methylene bisphenyl isocyanate (MDI), and hexamethylene diisocyanate (HDI) are known sensitizers and exposure to these chemicals can result in isocyanate-induced asthma-the leading cause of occupational asthma. A newly created exposure database was available containing occupational isocyanate measurements spanning 1981-1996 from Ontario and British Columbia (BC)-two of the largest provinces in Canada. The aim was to describe the historical measurements relative to exposure thresholds, ascertain differences in the data between provinces, and identify time trends. Descriptive statistics of the observations were summarized and stratified by isocyanate species and province. Chi-square tests and Student's t-test were performed to determine differences between provinces. To investigate time trends in the odds of a measurement exceeding the limit of detection (LOD) and time-weighted average (TWA), mixed effects logistic regression models were constructed. In total, 6,984 isocyanate measurements were analyzed, the majority of which were below the LOD (79%). Overall, 8.3% of samples were in excess of the 2014 TLV-TWA of 0.005 ppm. Comparing the two provinces, the proportion of samples exceeding the LOD and TLV-TWA was greater in BC for all isocyanate species. Differences in time trends were also observed between provinces-the odds of a sample exceeding the TLV-TWA decreased over time in the case of MDI (Ontario only), TDI (both Ontario and BC), and other isocyanates (BC only). Our finding that a majority of the exposure measurements was below the LOD is similar to that reported by others. Differences between provinces may be due the fact that isocyanates are classified as a designated substance in Ontario and must adhere to specific exposure control regulations. Limitations of the database, such as finite number of variables and measurements available until 1996 only, presents challenges for more in-depth analysis and generalization of results. An argument is made that a Canadian occupational exposure database be maintained to facilitate risk assessments as well as for occupational epidemiology research.

Workers with hand dermatitis and workplace training experiences: A qualitative perspective

BACKGROUND

Workplace training may help to prevent contact dermatitis, a common work-related disease. Information on the characteristics of existing workplace training programs and worker perceptions of this training is limited.

METHODS

Fourteen workers with suspected occupational contact dermatitis participated in one-on-one, semi-structured interviews. An inductive thematic analysis approach was used to identify interview themes.

RESULTS

Workers expressed a desire for hands-on training with content relevant to their job tasks, favored training from supervisors who had practical experience, and were conflicted about employer motivations for providing training. Few workers had received training on skin protection. In many cases, the training workers had received differed greatly from their desired training.

CONCLUSIONS

Although, workers with contact dermatitis describe having received workplace training, some question its value and effectiveness. This perspective may be attributed not only to the content and methods of training but also the health and safety culture of the workplace. Am. J. Ind. Med. 60:69-76, 2017. © 2016 Wiley Periodicals, Inc.

Designing exposure registries for improved tracking of occupational exposure and disease

OBJECTIVES

Registries are one strategy for collecting information on occupational exposure and disease in populations. Recently leaders in the Canadian occupational health and safety community have shown an interest in the use of occupational exposure registries. The primary goal of this study was to review a series of Canadian exposure registries to identify their strengths and weaknesses as a tool for tracking occupational exposure and disease in Canada. A secondary goal was to identify the features of an exposure registry needed to specifically contribute to prevention, including the identification of new exposure-disease relationships.

METHODS

A documentary review of five exposure registries from Canada was completed. Strengths and limitations of the registries were compared and key considerations for designing new registries were identified.

RESULTS

The goals and structure of the exposure registries varied considerably. Most of the reviewed registries had voluntary registration, which presents challenges for the use of the data for either surveillance or epidemiology. It is recommended that eight key issues be addressed when planning new registries: clear registry goal(s), a definition of exposure, data to be collected (and how it will be used), whether enrolment will be mandatory, as well as ethical, privacy and logistical considerations.

CONCLUSIONS

When well constructed, an exposure registry can be a valuable tool for surveillance, epidemiology and ultimately the prevention of occupational disease. However, exposure registries also have a number of actual and potential limitations that need to be considered.

Urinary metal concentrations among female welders

As part of a Canada-wide study of women entering non-traditional trades [Women's Health in Apprenticeship Trades-Metalworkers and Electricians (WHAT-ME)], we examined spot urine samples from women welders in Alberta to determine whether urinary metal concentrations exceeded those of the general population, to compare levels to previously published urinary concentrations in male welders and to examine the relationship with welding tasks. Women mailed-in urine samples collected close to the time of completing a detailed exposure questionnaire, including welding tasks on their most recent day welding at work. Of 53 welders working in their trade, 45 had urinary creatinine >0.3-≤3.0g l(-1) and were included in analyses. Seven metals were examined for which both population and male welder urinary concentrations were available: cadmium, chromium, cobalt, copper, manganese, nickel, and zinc. Principal component analysis was used to extract three components from natural log transformed creatinine-corrected metal concentrations. Of the 45 women, 17 reported more than one main task. Overall two thirds worked in fabrication, a third on pipe welding, and smaller numbers on repair, in construction or other tasks: manual metal arc welding was reported by 62%, semi-automatic arc welding by 47%, and arc welding with a tungsten electrode by 15%. In multiple regression analyses, little relation was found between urinary metals and task or type of welding, except for cadmium where lower levels were seen in those reporting semi-automatic manual welding (after adjustment for age and smoking). The proportion of women welders exceeding the selected general population 95th percentile was high for manganese (96%) and chromium (29%). Urinary metal concentrations were similar to those reported for male welders with only manganese, with a geometric mean in women of 1.91 µg g(-1) creatinine, and perhaps copper (11.8 µg g(-1) creatinine), consistently lower in male welders. Although not evident from the task analysis reported here, differences in exposure by sex may be explained by type of welding or by other work practices. A closely comparable cohort of male welders would be necessary to examine this hypothesis more fully.

Educational intervention among farmers in a community health care setting

BACKGROUND

Farmers are at increased risk of developing work-related respiratory diseases including asthma, but little is known about their occupational health and safety (OHS) knowledge and exposure prevention practices. Educational interventions may improve knowledge and practice related to prevention.

AIMS

To determine the feasibility of an educational intervention for farmers in a community health centre setting.

METHODS

This was a pilot study. Farmers were recruited by the community health centre and completed a questionnaire on symptoms, OHS knowledge and exposure prevention practices. The intervention group received education on work-related asthma and exposure control strategies, and was offered spirometry and respirator fit testing. All subjects were asked to repeat the questionnaire 6 months later.

RESULTS

There were 68 study participants of whom 38 formed the intervention group. At baseline, almost 60% of farmers reported having received OHS training and were familiar with material safety data sheets (MSDSs); fewer (approximately 40%) reported knowledge of OHS legislation and availability of MSDSs. Approximately, two-thirds of subjects reported using respiratory protection. The response rate for repeating the questionnaire was 76% in the intervention group and 77% in the controls. Among the intervention subjects, statistically significant increases were observed in reported safety training, familiarity and availability of MSDSs and knowledge of OHS legislation.

CONCLUSIONS

Gaps in OHS knowledge were observed. The educational intervention on OHS knowledge and exposure prevention practices in the community health centre setting was feasible. Larger, more-controlled studies should be undertaken as this study suggests a positive effect on OHS knowledge and prevention practices.

Occupational contact allergens: are they also associated with occupational asthma?

BACKGROUND

Workplace exposures that can potentially cause both allergic occupational contact dermatitis (AOCD) and occupational asthma (OA) are not clearly identified.

METHODS

Occupational contact allergens (OCAs) were identified using North American Contact Dermatitis Group (NACDG) data. Reference documents and systematic reviews were used to determine whether each OCA had been reported to potentially cause OA. The presence or absence of a sensitizer notation in occupational hygiene reference documents was also examined.

RESULTS

The 10 most common OCAs were: epoxy resin*, thiuram, carba mix, nickel sulfate*, cobalt chloride*, potassium dichromate*, glyceryl thioglycolate, p-phenylenediamine*, formaldehyde* and glutaraldehyde*. Seven (indicated by *) were determined to be possible causes of OA. Information on sensitizing potential from OH reference materials contained conflicting information.

CONCLUSIONS

Several common OCAs can also potentially cause OA. Inhalation and dermal exposures to these agents should be controlled and both OA and AOCD should be considered as possible health outcomes. Increased consistency in sensitizer notations is needed.

Exposure assessment in cohort studies of childhood asthma

BACKGROUND

The environment is suspected to play an important role in the development of childhood asthma. Cohort studies are a powerful observational design for studying exposure-response relationships, but their power depends in part upon the accuracy of the exposure assessment.

OBJECTIVE

The purpose of this paper is to summarize and discuss issues that make accurate exposure assessment a challenge and to suggest strategies for improving exposure assessment in longitudinal cohort studies of childhood asthma and allergies.

DATA SYNTHESIS

Exposures of interest need to be prioritized, because a single study cannot measure all potentially relevant exposures. Hypotheses need to be based on proposed mechanisms, critical time windows for effects, prior knowledge of physical, physiologic, and immunologic development, as well as genetic pathways potentially influenced by the exposures. Modifiable exposures are most important from the public health perspective. Given the interest in evaluating gene-environment interactions, large cohort sizes are required, and planning for data pooling across independent studies is critical. Collection of additional samples, possibly through subject participation, will permit secondary analyses. Models combining air quality, environmental, and dose data provide exposure estimates across large cohorts but can still be improved.

CONCLUSIONS

Exposure is best characterized through a combination of information sources. Improving exposure assessment is critical for reducing measurement error and increasing power, which increase confidence in characterization of children at risk, leading to improved health outcomes.