High urinary bisphenol A concentrations in workers and possible laboratory abnormalities

Objectives Bisphenol A (BPA) is widely used in epoxy resins in China. There are few reports on the adverse health effects of occupational exposure to BPA. This study examined associations between urinary BPA concentrations in workers and laboratory parameters for health status. Methods Spot urine checks at the end shift on Friday were used for cross-sectional analysis of BPA concentrations, and blood or urinary markers of liver function, glucose homeostasis, thyroid function and cardiovascular diseases were measured. The 28 participants were workers in two semiautomatic epoxy resin factories. Results The average urinary BPA concentration was 55.73 +/- 5.48 ng/ml (geometric mean +/- geometric SD) (range 5.56-1934.85 ng/ml). After adjusting for urine creatinine (Cr), it was 31.96 +/- 4.42 mu g/g Cr (geometric mean +/- geometric SD) (range 4.61-1253.69 mu g/g Cr). BPA feeding operators showed the highest concentrations, over 10 times those of the crushing and packing and office workers. Higher BPA concentrations were associated with clinically abnormal concentrations of FT3, FT4, TT3, TT4, thyroid-stimulating hormone, glutamic-oxaloacetic transaminase and gamma-glutamyl transferase. Workers with higher BPA concentrations showed higher FT3 concentrations (linear trend: p < 0.001). Bivariate correlation tests for laboratory analytes within normal limits showed FT3 to be positively associated with logged BPA concentrations, r=0.57, p=0.002. FT4 was positively associated with lactate dehydrogenase, r-0.45, p-0.020, and insulin was positively associated with thyroid- stimulating hormone with r=0.57, p=0.009. Conclusions Higher occupational BPA exposure, reflected in urinary concentrations of BPA, may be associated with thyroid hormone disruption.