A longitudinal observation of early pulmonary responses to cotton dust

Abstract

Aims: To examine early adverse pulmonary effects of exposure to cotton dust, and to identify potential risk factors, including atopy for pulmonary responses to cotton dust.

Methods: Spirometry, methacholine challenge testing, and questionnaire; performed among 101 non-smoking newly hired textile workers at baseline (prior to starting work), and at 3, 12, and 18 months after starting work. Concentrations of airborne cotton dust in various work areas were measured at each follow up survey using vertical elutriators.

Results: The incidence of non-specific respiratory symptoms was 8% at three months, then diminished afterwards. Substantial acute cross shift drops in FEV₁ at each follow up survey, and longitudinal declines in FVC and FEV₁ after 12 months of exposure were observed. Airway responsiveness to methacholine increased with follow up time, and was more pronounced among atopics. Increasing airway responsiveness was strongly correlated with cross shift drops in FEV₁. In addition, one or more respiratory symptoms at three months was significantly, and pre-existing atopy marginally significantly, associated with cross shift drops in FEV₁ after adjusting for other covariates and confounders.

Conclusion: Results suggest that non-specific respiratory symptoms, decreasing lung function, and increasing airway responsiveness are early pulmonary responses to cotton dust. In addition, the occurrence of respiratory symptoms and increasing airway responsiveness, as well as atopy, may be important predictors for acute changes in lung function among cotton textile workers.