Respiratory symptoms and lung function in bauxite miners

Objectives: To determine whether cumulative bauxite exposure is associated with respiratory symptoms or changes in lung function in a group of bauxite miners. Methods: Current employees at three bauxite mines in Australia wer e invited to participate in a survey comprising: questionnaire on demograph ic details, respiratory symptoms, and work history; skin prick tests for fo ur common aeroallergens; and spirometry. A task exposure matrix was constru cted for bauxite exposure in all tasks in all jobs based on monitoring data . Data were examined for associations between cumulative bauxite exposure, and respiratory symptoms and lung function, by regression analyses. Results : The participation rate was 86%. Self-reported work-related respiratory sy mptoms were reported by relatively few subjects (1.5%-11.8%). After adjustm ent for age and smoking no significant differences in the prevalence of res piratory symptoms were identified between subjects, in the quartiles of cum ulative bauxite exposure distribution. The forced expiratory volume in 1 s (FEV1) of the exposed group was found to be significantly lower than that f or the unexposed group. After adjustment for age, height, and smoking there were no statistically significant differences between quartiles in FEV1, f orced vital capacity (FVC) and FEV1/FVC ratio. Conclusions: These data prov ide little evidence of a serious adverse effect on respiratory health assoc iated with exposure to bauxite in an open-cut bauxite mine in present day c onditions.