A Longitudinal Study of Lung Function in Non-asthmatic Workers in an Aluminum Smelter.

This paper reports a longitudinal study carried out between 1977 and 1989 to determine whether the long-term rate of change in the forced expiratory volume in 1 second (FEV&inf1;) is influenced by exposure to the potroom environment of an aluminum smelter. Workers with diagnosed asthma were excluded from the analysis. The study population consisted of 393 potroom workers, with rate of change in FEV&inf1; used to assess any impairment in airway function. Post-shift urinary fluoride levels and length of service were used to measure exposure. After allowing for age, smoking behavior, and a standardized measure of FEV&inf1;, the rate of change in FEV&inf1; was found to be significantly greater for those workers who had worked shorter times in the potroom. Possible explanations for this finding include unrecognized asthma, a healthy-worker effect, and an exposure effect that occurs early in a worker's experience in the potroom; these explanations are not necessarily mutually exclusive. Apart from the risk of occupational asthma, there does not appear to be any long-term effect on the rate of decline in FEV&inf1; associated with exposure to the potroom environment in workers who remain at work longer than 40 months.