Exposure, lung function decline and systemic inflammatory response in asphalt workers

Abstract

Objectives: The aim of this study was to determine the association between exposures in asphalt work and changes in lung function, blood concentrations of interleukin-6 (IL-6), micro-C-reactive protein, and fibrinogen among asphalt workers during a work season. Methods: Blood samples from all asphalt workers (N=140) in Norway's largest road construction and maintenance company were taken in April-May 2005 and again in September-October 2005. Spirometric tests of the asphalt workers and a reference group (heavy construction workers, N=126) were carried out before the asphalt season, and the asphalt workers were tested again at the end of the season. Exposure to total dust, oil mist, polycyclic aromatic hydrocarbons, and gases was measured by personal samplers during the asphalt season. Results: The asphalt workers had a significantly a lower forced expiratory volume in 1 second (FEV1) and forced expiratory flow rate of 50% of the forced vital capacity than the reference group at the beginning of the season. The asphalt workers were divided according to their exposure into two groups, asphalt pavers (N=81) and asphalt plant operators and truck drivers (N=54). The screedmen, a group of the asphalt pavers, had a statistically significant lower FVC and FEV1 after one season of asphalt work than all of the other asphalt workers (P<0.05). The mean plasma concentration of IL-6 increased among the asphalt pavers from 1.55 pg/ml before the season to 2.67 pg/ml at the season's end (P=0.04, adjusted for current smoking). Conclusions: Exposure in asphalt paving may enhance the risk of lung function decline.