High alveolar nitric oxide is associated with steeper lung function decline in foundry workers

Occupational dust exposure induces inflammatory responses that often precede the onset of clinical disease. Inflammation in the peripheral part of the lung can be demonstrated by measuring the alveolar NO concentration (CANO) in exhaled breath. The aim of the study was to assess whether cumulative dust exposure affects the change in CANO during follow-up and whether baseline CANO can predict an impairment in lung function during follow-up in foundry workers. We examined 74 dust-exposed and 42 nonexposed foundry workers and measured CANO and lung function at baseline and after 7 years of follow-up. An increase in CANO during the follow-up period was positively associated with cumulative dust exposure in foundry work (p= 0.035). Furthermore, a higher baseline CANO was associated with an accelerated decline in the forced vital capacity (FVC) during the follow-up period (absolute decrease in FVCp= 0.021, relative decrease in FVCp= 0.017). Higher cumulative dust exposure in foundry work is associated with a greater increase in CANO during follow-up, suggesting ongoing pulmonary inflammation in these subjects. Importantly, a high baseline CANO is associated with an accelerated decline in lung function, suggesting that CANO measurements might serve as a screening tool for high-risk workers.