One-year longitudinal study of young apprentices exposed to airway occupational sensitizers.

BACKGROUND The prevalence of diagnosed asthma and wheezing in young subjects is increasing; among environmental risk factors, occupational exposure can play a relevant role. STUDY OBJECTIVES The purpose of the study was to evaluate the effects of occupational exposure to a large variety of irritants and/or sensitizers on the incidence of respiratory symptoms and pulmonary function impairment in a group of young apprentices during the first year of work exposure, and to determine the prevalence of asthma-like symptoms and the role of different risk factors (gender, smoking habit, atopy and occupational exposure) in this young population. DESIGN AND METHODS We studied 448 young apprentices at the first pre-employment evaluation with a standardized questionnaire, spirometry and skin prick tests; in 244 of them clinical and functional evaluation was repeated after 1 year exposure to respiratory irritants or sensitizers. RESULTS At the first examination, males had higher prevalence of attacks of shortness of breath with wheeze, diagnosis of asthma, smoking habit and atopy than females. At the second examination there was no significant increase in the prevalence of respiratory symptoms. However, incident cases for cough, phlegm, wheezing, shortness of breath with wheeze (SOBWHZ) and asthma were all higher than remittent cases. Incidence of respiratory symptoms was associated with atopy and smoking habit. CONCLUSIONS Respiratory symptoms slightly increase over 1 year occupational exposure to sensitizers or irritants. The loss at the follow-up of subjects with higher smoking habit suggests a small "health worker effect" and could underestimate the effect of occupational exposure in apprentices.