Foundry work is a known risk factor for airway inflammation and chronic obstructive pulmonary disease. In this follow-up study, we show that an increase in the plasma level of adipsin is associated with higher dust exposure and the development of airway obstruction in foundry workers. Objective: The aim of the study was to assess whether plasma adipokine levels (adipsin, adiponectin, leptin, and resistin) are associated with pulmonary function in foundry workers. Methods: We examined 65 dust-exposed foundry workers and 40 nonexposed controls and analyzed their lung function and plasma adipokine levels at baseline and after approximately 7 years of follow-up. Results: A higher increase in plasma adipsin was associated with the development of airway obstruction in exposed subjects during follow-up after adjusting for body mass index changes during the follow-up period. Furthermore, the increase in adipsin levels was positively associated with cumulative dust exposure even after adjusting for smoking and body mass index changes during follow-up (P = 0.015). Conclusion: The results suggest that plasma adipsin is involved in the pathogenesis of subclinical airway inflammation and the development of chronic obstruction and is induced by occupational dust exposure. [ABSTRACT FROM AUTHOR]