Metalworking fluid-associated respiratory morbidity in a production facility with a cluster of lymphocytic bronchiolitis

Introduction: A cluster of lymphocytic bronchiolitis occurred in a facility where in-use metalworking fluid (MWF) had microbial growth. Aims: Evaluate the respiratory health of the current workforce and assess relationships with markers of MWF and microbial exposures. Methods: 388 (89%) workers were interviewed and performed spirometry. We collected 40 area and 104 personal air samples for total thoracic aerosol, MWF, and endotoxin. Mean concentrations by job group were used to assign exposures. We examined trends in health outcomes by exposure using generalized linear models adjusted for age and smoking. Results: Most participants were male (91%), never-smokers (68%), with mean age of 42 years (range: 19-65) and mean facility tenure of 15 years (range: 1-40). Forty-nine (13%) reported dyspnea, 47 (12%) cough, and 129 (33%) wheeze; 14 (4%) had a spirometric abnormality. Mean total thoracic aerosol ranged from below the limit of detection ( 3 , mean MWF from 3 , and mean endotoxin from 3 . Respiratory symptom prevalence increased with increasing exposure. Mean total thoracic aerosol was significantly associated with cough; mean MWF with dyspnea, cough, and wheeze; and mean endotoxin with dyspnea. Mean %predicted FEV1 was significantly lower in those reporting dyspnea (101.9 vs. 93.3), cough (102.1 vs. 94.7), and wheeze (102.5 vs. 98.1), but we found no associations between spirometric parameters and exposure. Conclusions: Associations between exposure and respiratory symptoms, but not lung function, could reflect early occupational lung disease and warrant further investigation.