Abstract

Background and aim: Risks for development of occupational sensitization, bronchial hyperresponsiveness, rhinoconjunctival and chest symptoms at work associated with continued exposure to high-molecular weight (HMW) allergens were estimated with three exposure assessment methods.

Methods: A Cox regression analysis with adjustment for atopy and smoking habit was done in 408 apprentices in animal health technology, pastry-making, and dental hygiene technology with an 8-year follow-up after training. The risk of continued exposure after training, estimated by the asthma-specific job exposure matrix (JEM), was compared to self reports and investigator-scores on job-training related exposure. Associations between outcomes and work duration in job(s) related to training were also evaluated.

Results: Exposure to animal-derived HMW allergens, subsequent to the apprenticeship period, as estimated by the JEM, was associated with a significantly increased risk for occupational sensitization (hazard ratio (HR) 6.4; 95% CI 2.3 to 18.2) and rhinoconjunctival symptoms at work (HR 2.6; 95% CI 1.1 to 6.2). Exposure to LMW agents significantly increased the risk of developing bronchial hyperresponsiveness (HR 2.3; 95% CI 1.1 to 5.4). Exposure verification appeared to be important to optimize the sensitivity and the specificity, as well as hazard ratios produced by the JEM. Self reports and investigator-scores also indicated that further exposure to HMW allergens increased the risk of developing occupational allergies. The agreement between self reports, investigator-scores, and the JEM were moderate to good. There was no significant association between respiratory outcomes and work duration in jobs related to training.

Conclusion: The asthma-specific JEM could estimate the risk of various outcomes of occupational allergies associated with exposure to HMW and LMW allergens, but it is relatively labour-intensive. Exposure verification is an important integrated step in the JEM that optimized the performance of the matrix