Search

Introduction: Contemporary asbestos exposure occurs during construction, remediation, and maintenance involving asbestos‐containing materials (ACM), as compared to the historical exposure scenarios of asbestos mining and milling. The Ontario Asbestos Workers Register (AWR) was established in 1986 to track asbestos exposure among construction workers. This study reports on the risk of asbestos‐related diseases (ARD) among workers in the AWR. Methods: AWR registrants were linked probabilistically with administrative health databases (1986–2019) to identify cases of ARD including both cancer and chronic respiratory disease. Follow‐up began at AWR enrollment and continued prospectively. Incidence rates were compared to the general population using standardized incidence ratios (SIRs). Associations between ACM exposure and ARD were estimated among AWR registrants using Poisson regression. Results: In total, 26,204 (81%) registrants were linked successfully. Common industries of employment were construction (62%), manufacturing (19%) and education (8%). Among men and women mesothelioma (M:SIR 6.83 [95% CI = 5.56−8.31]; W:SIR 19.2 [3.86−56.1]) and pulmonary fibrosis (M:SIR 14.1 [12.2−16.2]; W:SIR 9.25 [2.49−23.7]) rates were higher than the general population. Asbestosis risk was elevated among men (M:SIR 11.2 [9.59−13.1]). Workers with longer reported exposures (≥140 h) had increased rates of lung cancer (RR 1.34 [1.10–1.63]), mesothelioma (RR 2.83 [1.75–4.58]), asbestosis (RR 3.07 [2.12–4.43]), chronic obstructive pulmonary disease (RR 1.42 [1.29–1.57]), and pulmonary fibrosis (RR 1.88 [1.35–2.62]). Conclusion: Exposure to asbestos in construction and building maintenance continues to contribute to ARD incidence. Despite a Canadian ban on asbestos in new products, exposures to existing ACM will persist from construction activities. The AWR offers an opportunity for ongoing surveillance of resulting ARD in Ontario. [ABSTRACT FROM AUTHOR]

A job-exposure matrix (JEM) is a tool that can estimate diesel engine exhaust (DEE) exposures. JEMs based on expert judgment or measurement data are limited by the information available at the time of development. Over time, more information about hazardous exposures is understood through additional measurements and peer-reviewed publications. This study presents a systematic approach to updating an existing DEE JEM using published data to better reflect current scientific knowledge. The literature was searched for occupational exposure studies that measured DEE as elemental carbon (EC) between January 2010 and May 2022. Four-digit North American Industry Classification System (NAICS) 2002 and National Occupational Classification-Statistics (NOC-S) 2006 codes were assigned to each identified subgroup within the studies. EC exposures were categorized as low (0–10 µg/m3), moderate (10–20 µg/m3), or high (>20 µg/m3). Weighted arithmetic means were calculated for each industry-occupation intersection (IOI) identified in the literature. These means were used to adjust, or retain, the existing exposure level within the JEM cells using a decision tree based on the number of studies, workplace locations, and pooled sample size of the weighted mean. Concordance was measured between the updated JEM (Diesel Exhaust in Canada JEM (DEC-JEM)), the previous (existing) JEM, and the Canadian Job-Exposure Matrix (CANJEM). Thirty-seven studies were identified from the published literature reporting on 53 unique IOIs (20 NAICS and 34 NOC-S codes), including occupations in the mining, construction, and transportation industries. Exposure levels for 66% of identified IOIs increased, most in construction and mining. After the decision tree's results were expanded to the full DEC-JEM, the exposure level of 486 IOIs (12.5% of DEC-JEM) and 286,710 workers (15.8% of DEE-exposed workers) increased. There was a significant correlation between qualitative exposure levels in the updated DEC-JEM and CANJEM (Kendall's τ = 0.364, p < 0.001). This study describes a systematic approach to updating an existing JEM to incorporate new scientific knowledge. The updated DEC-JEM better reflects existing exposure knowledge in several industries, particularly construction. Future analyses include investigating its use as an exposure assessment tool in disease surveillance. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]