Abstract

Around 15% of adult asthma may be attributable to occupational exposures. Among adults with asthma, occupational exposures have also been associated with disease exacerbations and poor asthma control. While the number of identified occupational asthmagens (hazards known to induce asthma) increases regularly, the burden of work-related asthma remains underestimated. Moreover, for some categories of exposure such as cleaning products, specific causal agents remain unclear, limiting the development of prevention strategies. Two of the main methodological challenges in epidemiological studies on work-related asthma are (1) exposure assessment, as a differential misclassification bias may be particularly important when exposure is self-reported; and (2) the healthy worker effect, as individual with asthma may change job shortly after experiencing work-related symptoms. New methodological approaches have been developed to address these two challenges and will be presented. Methods for evaluation of exposure to specific cleaning products and disinfectants will be discussed, illustrating the interest of using (a) job-task-exposure matrices instead of common job-exposure matrices or self-report to reduce exposure misclassification; and (b) a smartphone application with a barcode reader to evaluate exposure to numerous chemicals contained in cleaning products/disinfectants. To address the healthy worker effect, new approaches based on causal inference methods have been developed in occupational epidemiology. The specific impact of the healthy worker effect in work-related asthma studies, and how it can be addressed using marginal structural models, will be presented. In summary, new epidemiological methods may help better evaluating the burden of work-related asthma, and improve ability to identify specific harmful agents, which is warranted to suggest new targets for work-related asthma prevention.