O-33 Potential occupational sensitizing exposures and development of asthma: an overview of systematic reviews

Introduction and Aim

Several hundred occupational agents are suspected to be able to cause asthma. However, the amount and type of evidence for these agents is not clear. As a first step, we aimed to identify, appraise, and synthesise the scientific evidence in systematic reviews of the relation between potential occupational sensitizing exposures and development of asthma.

Material and Methods

We conducted a systematic literature search where the study criteria included persons in or above working age, potential occupational sensitizing exposures, outcome defined as asthma, and study design restricted to systematic reviews. Potential occupational sensitizing exposures were divided into 23 main groups comprising both subgroups and specific exposures. Two of the authors independently selected studies and extracted study data. Assessment of study quality and evaluation of the confidence in each systematic reviews level of evidence was performed using AMSTAR 2.

Results

A total of 27 systematic reviews were included comprising 1242 studies and 486 potential occupational sensitizing exposures. Three systematic reviews were rated as having high quality, 7 moderate quality, and 17 low quality. We found strong evidence for the main group of wood dusts and moderate evidence for the main groups of mites and fish. For subgroups/specific exposures, strong evidence was found for toluene diisocyanates, Aspergillus, Cladosporium, Penicillium, and work tasks involving exposure to laboratory animals, whereas moderate evidence was found for another 52 subgroups/specific exposures.

Conclusion

In systematic reviews we identified hundreds of potential occupational sensitizing exposures suspected to cause asthma. Strong evidence was found for wood dust in general and for toluene diisocyanates, Aspergillus, Cladosporium, Penicillium, and work tasks involving exposure to laboratory animals. However, several well establishes sensitizers (e.g. enzymes, house dust mites, allergens from pets) have not or rarely been included in systematic reviews of occupational exposures, which is a limitation of the overview approach.