Work-related asthma (WRA) is the most common chronic occupational lung disease in the developed world. Several factors including socio-demographic status, and occupation / industry, increase the risks of developing WRA. In this study, we sought to identify changes in patterns and characteristics among WRA patients over a fifteen-year period in an occupational lung disease clinic.
We performed a retrospective analysis of WRA patient charts at the Occupational Lung Disease Clinic of a University Hospital in Toronto, Canada. Patients were divided into two periods classified by first attendance at the clinic 2000-2007 and 2008-2015. Comparisons between the two periods included: socio-demographic characteristics, smoking status, occupations, exposures, and submitted workers’ compensation claims.
Fewer occupational asthma cases were seen in the more recent period versus the earlier period (40 vs. 74 cases), with a smaller reduction in work-exacerbated asthma cases (40 vs. 58). The recent period included a significantly smaller proportion employed in the manufacturing industry and isocyanate-induced cases compared with the earlier period. An increased proportion were employed in health care and education industries (primarily cleaners and teachers) in the recent period, consistent with a corresponding increased frequency of cleaning agents and dust exposures.
The changes observed in work sectors in our work-related asthma patients in this clinic in Toronto are consistent with reductions reported in Ontario workers’ compensation claims for occupational asthma, and may relate to preventive measures. Cleaners and teachers should be a focus of further intervention measures for work-related asthma.