RELATION BETWEEN EXPOSURE TO FLUORIDE AND BRONCHIAL RESPONSIVENESS INALUMINUM POTROOM WORKERS WITH WORK-RELATED ASTHMA-LIKE SYMPTOMS

Background - The relation between plasma fluoride levels and bronchial responsiveness was investigated in a longitudinal study in aluminium potroom workers who reported work-related asthmatic symptoms. Methods - From a cross-sectional respiratory survey, 26 men who reported work- related asthmatic symptoms on a validated questionnaire were selected for repeated measurements of bronchial responsiveness to methacholine. Regular analyses of plasma fluoride levels were performed. Exposure t o fluoride and total particulates was assessed from routine surveillan ce of the workplace. Bronchial responsiveness was expressed as the dos e-response slope of the line through the origin and last data point. R esults - A positive association was found between bronchial responsive ness and plasma fluoride levels, such that an increase in the plasma f luoride level of 10 ng/ml was associated with an increase in the dose- response slope by a factor of 1.11 (95% confidence interval 1.05 to 1. 17). Plasma fluoride levels were associated with the total atmospheric fluoride concentration in mg/m(3) (beta = 28.1), but not with total p articulates in the environment. Conclusions - Bronchial responsiveness in aluminium potroom workers reporting work-related asthmatic symptom s appears to be related to plasma levels of fluoride. The underlying m echanism is, however, unknown.