Risks of Exposure to Occupational Asthmogens in Atopic and Nonatopic Asthma: A Case-Control Study in Taiwan

Rationale: Asthma is often work-related and can be classified as atopic or nonatopic on the basis of its pathogenesis. Few studies have reported an association between exposure to occupational asthmogens and asthma with and without atopy.Objectives: We investigated, in adults with asthma, whether occupational exposure to asthmogens influenced the risk of having atopic or nonatopic asthma, and their level of lung function.Methods: We recruited 504 hospital-based adults with current asthma, 504 community-based control subjects, and 504 hospital-based control subjects in southern Taiwan. Asthma with atopy was defined as having asthma in combination with an increase in total IgE (≥100 U/ml) or a positive Phadiatop test (≥0.35 Pharmacia arbitrary unit/L) (Pharmacia ImmunoCAP; Pharmacia, Uppsala, Sweden). Occupational exposure to asthmogens was assessed with an asthma-specific job exposure matrix.Measurements and Main Results: We found a significant association between atopic asthma and exposure to high molecul...