Biliary Function in Workers Occupationally Exposed to Aluminium Dust and Fumes

Abstract

This study investigated biliary secretory function in workers occupationally exposed to aluminium dust and fumes. It included a group of 34 male workers aged (44.1+/-7.8) years and exposed up to 4.6 mg m-3 of aluminium dust and fumes in workplace air for (21.6+/-2.5) years, and a group of 30 unexposed control male workers. Serum and urine aluminium levels were measured in both groups before and after chelating treatment with 1 g deferoxamine by intramuscular injection. Biliary function was assessed by measuring gamma-glutamyl transpeptidase, alkaline phosphatase, 5-nucleotidase, cholesterol and its fractions, total and indirect bilirubin, and bile acids. We then analysed the relationship between Al exposure and biliary function. In the exposed group mean serum aluminium was significantly higher [(4.91+/-3.86) microg L-1] than in controls. The same was true for urine Al before [(1.57+/-1.93) microg L-1] and after deferoxamine [(11.51+/-14.97) microg L-1]. Total and indirect bilirubin and alkaline phosphatase were significantly higher in the exposed than in control workers, and they correlated with urine Al after the chelating treatment. Our findings suggest that chronic occupational exposure to aluminium dust and fumes leads to a significant body retention of aluminium. The impaired biliary secretion in the exposed workers manifested itself in subclinical signs of cholestasis.