The characteristics of work-related asthma in a prospective asthma cohort

Abstract

Background: Work-related asthma(WRA) occupies about 30% of all asthma;two subtypes of WRA,occupational asthma(OA) and work-exacerbated asthma(WEA) accounts for about 2/3 and 1/3 of WRA,respectively.However,these data were mainly based on indirect surveys.Ulsan is the most industrialized city in Korea,therefore it is expected that Ulsan has many WRA patients. Objectives: To know the exact prevalence of WRA in an industrialized city through a prospective clinical asthma cohort,and to know characteristics of WRA. Methods: Since JAN 2015, those who had been diagnosed with asthma at Ulsan Univ.Hosp. were recruited prospectively.At enrollment,clinical and work-related data were gathered.Every 6 months,the revaluation was performed. Results: Study is expected to last for at least 2 years,and the present data are interim results of 166 enrolled asthma patients for 1 year.WRA was 16.3%(27/166);OA and WEA occupied 77.8% and 22.2% of WRA.Before surveying work-relatedness,only 29.6% had been assessed as WRA by attending physicians.The major causes of WRA were chemical materials and exhaust gas/smoke in OA,whereas isocyanate and metal/metal-working fluid in WEA.Comparing OA,WEA had a long duration and a non-eosinophilic phenotype.Otherwise, there were no between-group differences in OA and WEA.Through revaluation at 6 months,we could know that severe asthma was more common in WEA than in OA (50% vs 10%, p=0.04). Conclusions: The prevalence of WRA was lower in the present study than in previous indirect studies.Work-relatedness survey should be routinized in all new asthmatics.The causes of WRA were different in OA and WEA.Compared to OA,WEA had a long duration,a non-eosinophilic phenotype,and was associated with severe asthma.