Prevalence and risk factors for work related asthma in young adults

Objectives: To investigate the prevalence and predictors of work related asthma in young adults from the general population. Methods: A total of 1922 subjects randomly selected from a birth cohort 1978/79 in Brazil, aged 23 - 25 years, completed a respiratory symptoms questionnaire based on the European Community Respiratory Health Survey, and underwent spirometry, bronchial challenge test with methacholine, and skin prick test. For subjects presenting with bronchial hyperresponsiveness, workplace exposure and its relationship with symptoms were assessed by a specific questionnaire and individualised job description to define cases of work related asthma. Results: The prevalence of work related asthma was 4.2% ( 81 cases): 1.5% ( 29 cases) were classified as aggravated asthma and 2.7% ( 52 cases) as occupational asthma. Work related asthma was associated with atopy and education. Lower educational level ( 1 - 8 years of schooling) was associated with work related asthma ( odds ratio 7.06, 95% CI 3.25 to 15.33). There was no association between work related asthma and smoking, gender, or symptoms of rhinitis. Conclusion: The prevalence of work related asthma was high ( 4.2%), and was associated with low schooling, probably because of low socioeconomic level. The disease may therefore be a consequence of poverty.