Early changes in clinical, functional, and laboratory biomarkers in workers at risk of indium lung disease.
RATIONALE: Occupational exposure to indium compounds including indium-tin oxide (ITO) can result in potentially fatal indium lung disease. However, the early effects of exposure on the lungs are not well understood. OBJECTIVES: To determine the relationship between short-term occupational exposures to indium compounds and development of early lung abnormalities. METHODS: Among ITO production and reclamation facility workers, we measured plasma indium, respiratory symptoms, pulmonary function, chest computed tomography, and serum biomarkers of lung disease. The relationships between plasma indium concentration and health outcome variables were evaluated using restricted cubic spline and linear regression models. MEASUREMENTS AND MAIN RESULTS: Eighty-seven (93%) of 94 ITO facility workers (median tenure=2 years; median plasma indium=1.0 mcg/L) participated in the study. Spirometric abnormalities were not in excess and few had radiographic evidence of alveolar proteinosis (n=0), fibrosis (n=2), or emphysema (n=4). Compared to participants with plasma indium concentrations <1.0 mcg/L, those with values >/=1.0 mcg/L had more dyspnea, lower mean FEV1% and FVC%, and higher median serum KL-6 and SP-D levels. Spline regression demonstrated non-linear exposure-response, with significant differences occurring at plasma indium concentrations as low as 1.0 mcg/L for FEV1%, FVC%, KL-6, and SP-D compared to the reference. Associations between health outcomes and plasma indium were evident in linear regression models and not explained by age, smoking status, or facility tenure. CONCLUSIONS: In ITO facility workers with short-term, low-level exposure, plasma indium concentrations lower than previously reported were associated with lung symptoms, abnormal spirometry, and increased serum biomarkers of lung disease.
Respiratory-system-disorders; Pulmonary-system-disorders; Lung-disorders; Indium-compounds; Tin-oxides; Oxides; Lung-disease; Employee-exposure; Short-term-exposure; Lung-function; Biomarkers; Chemical-manufacturing-industry; Chemical-factory-workers; Humans; Spirometry; Alveolar-cells; Lung-fibrosis; Blood-serum; Dose-response; Mathematical-models
Kristin J Cummings CDC/NIOSH, Division of Respiratory Disease Studies, Morgantown, West Virginia, United States, 26505