Associations between environmental exposures and serum concentrations of Clara cell protein among elderly men in Oslo, Norway.

Cardiopulmonary morbidity and mortality is associated with several environmental exposures. Mechanistically, pathophysiological changes in the cardiopulmonary system may lead to the induction of inflammatory responses. In the present study we explored associations between environmental exposures and serum concentrations of lung Clara cell protein 16kDa, a biomarker that has recently been used to assess the integrity of the lung epithelium. Serum Clara cell protein concentrations were associated with both number of cigarettes smoked per day and number of pack-years of smoking. There was no evidence of an association between long-term exposure to ambient air pollution, as assessed at each participant's home address, and serum concentrations of CC16. However, short-term variations in both ambient air pollution and temperature were associated with increases in serum Clara cell concentrations. All findings were robust when other factors were adjusted for. These findings suggest that acute environmental exposures may compromise the integrity of the lung epithelium and lead to increased epithelial barrier permeability in the lungs of elderly men.