Background: Whether new-onset asthma is associated with irritant exposure is unclear. The aim was to investigate if occupational exposure to irritant gases, especially repeated peak exposure (gassings), increased the risk of obstructive airways disease.
Methods: Data on airway symptoms and exposure among bleachery (n = 101) and paper department workers (n = 314) were collected by a questionnaire. Incidence rates and hazard ratios (HR) (Cox regression) were calculated. Non-responders were interviewed by telephone.
Results: The incidence rate for adult-onset physician-diagnosed asthma among bleachery workers reporting gassings giving rise to respiratory symptoms was 7.6/10(3) person-years and for those without gassings 2.2/10(3) person-years, compared to 1.0/10(3) person-years for paper workers. In a Cox regression model for asthma (n = 12), stratified for sex, HR for gassings were 5.6 (95% confidence intervals (CI) 1.6-20), for hay fever 3.0 (95% CI 0.8-11), and for ever smoking 0.7 (95% CI 0.2-2.4). The same model for adult-onset wheeze gave HR of 5.2 (95% CI 2.2-12), 1.7 (95% CI 0.6-5.4), and 1.1 (95% CI 0.5-2.7), respectively.
Conclusions: Repeated peak exposure to irritant gases, here studied as gassings in the pulp industry, increased the risk for both adult-onset asthma and wheeze.
Copyright 2003 Wiley-Liss, Inc.