Surveillance of asbestos related disease among workers enrolled in an exposure registry

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.

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.

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]).

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.