AIRWAY HYPERRESPONSIVENESS IN WORKERS EXPOSED TO LOW-LEVELS OF IRRITANTS

The purpose of this study was to assess the association between occupa tional exposure to low levels of airway irritants, and airway responsi veness to histamine. In 688 male workers, symptom prevalence was asses sed according to the British Medical Research Council (BMRC) questionn aire, Ah subjects performed a 30 s tidal breathing challenge test. Air way hyperresponsiveness (AHR) was defined as a 20% fall in forced expi ratory volume in one second (FEV(1)) at less than or equal to 32 mg . ml(-1) histamine, On the basis of job titles and working department, t he exposure status of all workers was characterized into seven groups: 1) reference group; 2) white collars; 3) SO2, HCl, SO42-; 4) polyeste r vapour; 5) oil mist and oil vapour; 6) polyamide and polyester vapou r; and 7) multiple exposures. Using multiple logistic regression, no a ssociation was found between the exposure groups and a higher prevalen ce of AHR. A higher prevalence was significantly associated with a low FEV(1), a history of allergy, and the presence of chronic respiratory symptoms, Subjects in the SO2 group and the oil mist group with less than or equal to 5 exposure years had a lower prevalence of ABR, proba bly due to pre-employment selection procedures, There was some trend f or subjects with more than 5 yrs exposure to polyester vapour and to o il mist and to oil vapour to have a higher prevalence of AHR Analyses using the dose-response slope according to O'Connor, revealed similar results and provides no additional information. We conclude that no as sociation could be demonstrated between low grade exposure to airway i rritants and airway hyperresponsiveness, and that further research is needed to elucidate this relationship.