Suchergebnisse

Abstract

Background:
In 2010, Ontario, Canada's most populous province, implemented its Toxics Reduction Act, Ontario Regulation 455/09 (TRA), which requires four major manufacturing and mineral processing industry groups that already report releases of pollutants federally to the National Pollutant Release Inventory to additionally track, account and report their use and creation. The TRA was modeled after the Massachusetts Toxics Use Reduction Act of 1989, which has been very successful and reported significant reduction in toxic use and carcinogen release.


Methods:
Data from the TRA were retrieved, and the trends in the use and release of 17 known and suspected carcinogens associated with the seven most prevalent cancers diagnosed in Ontario and reported by industrial facilities in Ontario from 2011 to 2015 were examined using methodology adapted from (Jacobs MM, Massey RI, Tenney H, Harriman E. Reducing the use of carcinogens: the Massachusetts experience. Rev Environ Health 2014;29(4):319–40).


Results:
Carcinogens associated with lung cancers, leukemia and lymphomas were observed as the most used and released carcinogens in Ontario by amount. Overall, for 2011–2015, there was an observed reduction in the industrial use of carcinogens, except among breast carcinogens, which increased by 20%. An increase in the industrial releases of carcinogens was observed across all cancer sites, except among lung carcinogens, which decreased by 28%.


Conclusion:
The results of this study highlight the potential for reducing the cancer burden by reducing the use and release of select carcinogens associated with particularly prevalent cancers. Toxics use reduction programs can support cancer prevention initiatives by promoting targeted reductions in exposures to industrial carcinogens.

Abstract

Objective
Asbestos use has decreased over time but occupational exposure still exists today due to the presence of asbestos in older buildings. The objective of this study was to update CAREX Canada's prevalence of exposure estimate from 2006 to 2016, and to assess the level of occupational exposure by industry, occupation, province/territory, and sex.


Methods
Estimates by occupation, industry, province/territory, and sex were calculated using labor force data from the 2016 Census of Population and proportions of workers exposed by occupation and industry, which were previously developed for the 2006 estimates and updated here to reflect new knowledge and changes in exposures. Statistics Canada concordance tables were used to account for changes between the 2006 and 2016 job and industry coding systems. Expert assessment was used to qualitatively assign levels of exposure (low, moderate, or high) for each occupation and industry, with consideration of workers' proximity and access to asbestos-containing material, and the condition and content of asbestos.


Results
Approximately 235 000 workers are exposed to asbestos on the job in Canada. The majority of Canadian workers exposed to asbestos are male (89%). Only 5% of all exposed workers are in the high-exposure category, while most workers are in the low (49%) or moderate (46%) exposure categories. The construction sector and associated jobs (e.g. carpenters, trades helpers and laborers, electricians) accounted for the majority of exposed workers.


Conclusions
Occupational exposure to asbestos continues to occur in Canada. Updating the prevalence of exposure estimate and adding exposure levels highlights the shift from high to lower-lever exposures associated with asbestos-containing materials remaining in the built environment.

Abstract
Despite numerous studies of asbestos workers in the epidemiologic literature, there are very few cohort studies of chrysotile asbestos miners/millers that include high-quality retrospective exposure assessments. As part of the creation of the Baie Verte Miners' Registry in 2008, a two-dimensional job exposure matrix (JEM) was developed for estimating asbestos exposures for former chrysotile asbestos miners/millers. Industrial hygiene data collected between 1963 and 1994 were analysed to assess validity for use in a retrospective exposure assessment and epidemiologic study. Registered former employees were divided into 52 exposure groups (EGs) based on job title and department and mean asbestos concentrations were calculated for each EG. The resulting exposure estimates were linked to individual registrants' work histories allowing for the calculation of cumulative asbestos exposure for each registrant. The distribution of exposure for most EGs (82.6%) could be described as fitting a log-normal distribution, although variability within some EGs (55%) exceeded a geometric standard deviation (GSD) of 2.5. Overall, the data used to create EGs in the development of the JEM were deemed to be of adequate quality for estimating cumulative asbestos exposures for the former employees of the Baie Verte asbestos mine/mill. The variability between workers in the same job was often high and is an important factor to be considered when using estimates of cumulative asbestos exposure to adjudicate compensation claims. The exposures experienced in this cohort were comparable to those of other chrysotile asbestos miners/millers cohorts, specifically Italian and Québec cohorts.

IntroductionWorkplace conditions and exposures are important determinants of health. However, identifying and monitoring population-level trends in work-related disease is challenged by existing data limitations. Administrative health databases capture timely and accurate information about disease diagnoses among the Ontario population, but these data do not include work history.
Objectives and ApproachThe Occupational Disease Surveillance System (ODSS), launched in 2017, captures and reports trends in work-related disease in Ontario. A cohort of 2+ million workers was identified from compensation claims (1983-2014). Records were linked through probabilistic and deterministic methods to the Registered Persons Database (1990-2015), and administrative health databases including the Ontario Cancer Registry (1964-2016), hospitalization (2006-2016), ambulatory care (2006-2016) and provincial health insurance plan billing data (1999-2016). Preliminary applications of ODSS have examined risks of 28 cancer sites and 11 non-cancer health conditions. Risks are estimated with Cox proportional hazards models for thousands of industry and occupation groups.
ResultsLinkage of existing administrative databases is an efficient approach for examining risk factors for work-related disease at the population level. ODSS can identify groups of workers by industry or occupation that are at increased risk of disease due to known or suspected workplace conditions and risk factors. For example, ODSS detected elevated risk of lung cancer among known at-risk workers employed in mining and quarrying (HR 1.47, 95% CI 1.33-1.61), transport equipment operating (HR 1.39, 95% CI 1.34-1.44), and construction (HR 1.09, 95% CI 1.06-1.13). Exploratory analyses can also detect previously unknown associations between work-related risk factors and disease. For example, although dermatitis and asthma are common occupational diseases, many causative exposures remain unclear. ODSS is currently being used to further explore potential risk factors.
Conclusion/ImplicationsTimely information about work-related disease is crucial to support prevention initiatives to protect workers. This novel linkage identifies existing and emerging trends in occupational disease in Ontario. By capturing work-related risk factors, ODSS serves as a model for other provinces to overcome existing gaps in disease surveillance.

AbstractObjectives:Occupational exposure to antineoplastic agents occurs in various environments and is associated with increased cancer risk and adverse reproductive outcomes. National-level information describing the location and extent of occupational exposure to antineoplastic agents is unavailable in Canada and most other countries. CAREX Canada aimed to estimate the prevalence and relative levels of occupational exposures to antineoplastic agents across work setting, occupation, and sex.Methods:'Exposure' was defined as any potential for worker contact with antineoplastic agents. Baseline numbers of licensed workers were obtained from their respective professional bodies. For unlicensed workers, Census data or data extrapolated from human resources reports (e.g., staffing ratios) were used. Prevalence was estimated by combining population estimates with exposure proportions from peer-reviewed and grey literature. Exposure levels (classified as low, moderate, and high) by occupation and work setting were estimated qualitatively by combining estimates of contact frequency and exposure control practices.Results:Approximately 75000 Canadians (0.42% of the total workforce) are estimated as occupationally exposed to antineoplastic agents; over 75% are female. The largest occupational group exposed to antineoplastic agents is community pharmacy workers, with 30200 exposed. By work setting, 39000 workers (52% of all exposed) are located in non-hospital settings; the remaining 48% are exposed in hospitals. The majority (75%) of workers are in the moderate exposure category.Conclusions:These estimates of the prevalence and location of occupational exposures to antineoplastic agents could be used to identify high-risk groups, estimate disease burden, and target new research and prevention activities. The limited secondary data available for developing these estimates highlights the need for increased quantitative measurement and documentation of antineoplastic agent contamination and exposure, particularly in work environments where use is emerging.

Abstract

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.

Abstract

Objectives
Shift work with circadian disruption is a suspected human carcinogen. Additional population-representative human studies are needed and large population-based linkage cohorts have been explored as an option for surveillance shift work and cancer risk. This study uses a surveillance linkage cohort and job-exposure matrix to test relationships.


Methods
We estimated associations between shift work and breast, ovarian, and prostate cancer using the population-based Canadian Census Health and Environment Cohort (CanCHEC), linking the 1991 Canadian census to national cancer registry and mortality databases. Prevalence estimates from population labour survey data were used to estimate and assign probability of night, rotating, or evening shifts by occupation and industry. Cohort members were assigned to high (>50%), medium (>25 to 50%), low (>5 to 25%), or no (<5%) probability of exposure categories. Cox proportional hazards modelling was used to estimate associations between shift work exposure and incidence of prostate cancer in men and ovarian and breast cancer in women.


Results
The cohort included 1 098 935 men and 939 520 women. Hazard ratios (HRs) indicated null or inverse relationships comparing high probability to no exposure for prostate cancer: HR = 0.96, 95% confidence interval (CI) = 0.91–1.02; breast cancer: HR = 0.94, 95% CI = 0.90–0.99; and ovarian cancer: HR = 0.99, 95% CI = 0.87–1.13.


Conclusions
This study showed inverse and null associations between shift work exposure and incidence of prostate, breast, or ovarian cancer. However, we explore limitations of a surveillance cohort, including a possible healthy worker survivor effect and the possibility that this relationship may require the nuanced exposure detail in primary collection studies to be measurable.

PURPOSE OF REVIEW: There are many opportunities and challenges for conducting occupational epidemiologic studies today. In this paper, we summarize the discussion of a symposium held at the Epidemiology in Occupational Health (EPICOH) conference, Chicago 2014, on challenges for occupational epidemiology in the twenty-first century. RECENT FINDINGS: The increasing number of publications and attendance at our conferences suggests that worldwide interest in occupational epidemiology has been growing. There are clearly abundant opportunities for new research in occupational epidemiology. Areas ripe for further work include developing improved methods for exposure assessment, statistical analysis, studying migrant workers and other vulnerable populations, the use of biomarkers, and new hazards. Several major challenges are also discussed such as the rapidly changing nature and location of work, lack of funding, and political/legal conflicts. As long as work exists there will be occupational diseases that demand our attention, and a need for epidemiologic studies designed to characterize these risks and to support the development of preventive strategies. Despite the challenges and given the important past contribution in this field, we are optimistic about the importance and continued vitality of the research field of occupational epidemiology.

Presumptive condition lists formally accept connections between military factors and veteran health conditions. An environmental scan of such lists and their evidentiary basis was conducted across four veterans' administrations to inform other administrations considering the development of such lists. Information on included conditions, qualifying military factors, and scientific processes was obtained through targeted internet searches and correspondence with veterans' administrations. The content of presumptive condition lists across jurisdictions varied by conditions included, as well as military eligibility requirements (e.g., service in particular conflict, context, or time period). Scientific review processes to develop lists also varied across jurisdictions. Findings indicate that evidence and experience may be leveraged across compensation systems (veteran and civilian). Ongoing research to understand links between military exposures and veteran health is recommended.

Abstract

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.