Occupational asthma in Europe and other industrialised areas: a population-based study

Background. There are no large population-based studies on occupational ast hma, and few estimates of the proportion of asthma attributed to occupation , even though asthma is the most common occupational respiratory disorder i n industrialised countries. Methods. We assessed data on 15637 people aged 20-44, randomly selected fro m the general population of 26 areas in 12 industrialised countries. Asthma was assessed by methacholine challenge test and by questionnaire data on r espiratory symptoms and use of medication. Occupation was defined by job-ti tles and a job exposure matrix was constructed. Findings. Highest risk of asthma, defined as bronchial hyperresponsiveness and reported asthma symptoms or medication, was shown for farmers (odds rat io 2.62 [95% Cl 1.29-5.35]), painters (2.34 [1.04-5.28]), plastic workers ( 2.20 [0.59-8.29]), cleaners (1.97 [1.33-2.92]), spray painters (1.96 [0.72- 5.34]), and agricultural workers (1.79 [1.02-3.16]). Similar risks were sho wn for asthma defined as reported asthma symptoms or medication. The most c onsistent results across countries were shown for farmers and cleaners. Exc ess asthma risk was associated with high exposure to biological dusts, mine ral dusts, and gases and fumes. The proportion of asthma among young adults attributed to occupation was 5%-10%. Interpretation. The prevalence of occupational asthma in women and in speci fic occupations has been underestimated. Given a mean prevalence of asthma of about 5%, about 0.2%-0.5% of young adults become asthmatics or have thei r asthma exacerbated because of their occupations.