Serum bile acid as a screening tool in workers occupationally exposed to mixtures of organic solvents

The aim of the present study was to find out the potential impact of occupational exposure to mixtures of organic solvents on liver function tests. Serum bile acid (BA) was evaluated as a marker of early hepatic derangement and compared to routine liver function tests. The study included two comparable groups: 57 male workers exposed to organic solvents from a paints factory and 59 administrative male controls. Occupational and medical data and serum analysis for liver function parameters (BAs, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP), total and direct bilirubin) were obtained. Bile acids showed significantly elevated mean levels in the exposed workers compared to the controls (50.2+/- 47.9 and 5.4+/- 2.7 mu mol/L, respectively, p < 0.01). Bile acids were elevated in almost all exposed workers (87.7%) but in none of the controls. Bile acids had significant positive correlation with duration of exposure to organic solvents and lifetime hydrocarbon exposure score (HES) (p < 0.01 and p < 0.05, respectively). All other liver function tests exhibited normal mean levels and did not show statistically significant differences between both groups. The performance of BA versus combined liver enzymes is evaluated using receiver-operating characteristic (ROC) curve and likelihood ratios. The area under the curve was significantly high (0.687 > 0.5, p=0.012) and had optimal decision level (8 mmol/L). Serum BA can be recommended as a screening test for exposure to organic solvents. It can be suggested for follow-up every 1-2 years or accordingly.