Examination of nervous system effects and other health effects in tunnel workers exposed to acrylamide and N-methylolacrylamide in Romeriksporten, Norway

OBJECTIVES: This study examined nervous system effects and other health effects in tunnel workers exposed to acrylamide and N-methylolacrylamide during tunnel work. METHODS: Symptoms and nerve conduction properties were recorded in 25 tunnel workers exposed to acrylamide and N-methylolacrylamide during grouting operations, four and 16 months after the cessation of exposure. Visual evoked response (VEP) and electroretinography (ERG) were performed 16 months post exposure. Hemoglobin adducts of acrylamide were measured and qualitative exposure indices were developed. Fifty unexposed tunnel workers served as referents. Chromosome aberrations and the distribution of Glutathion S transferase (GST) genotypes (M and T) were also examined in the 25 exposed workers, and were compared to 25 age and smoking matched referents. RESULTS: The exposed workers reported an increased prevalence of symptoms during grouting work compared to the examination after 16 months. A statistically significant reduction in mean sensory nerve conduction velocity (NCV) in the ulnar nerve was observed 4 months post exposure when compared to the reference group (52.3 vs. 58.9 m/s, p=0.001), and mean ulnar distal delay was prolonged (3.1 vs 2.5ms, p=0.001). Both measures were significantly improved when measured one year later. By correlating outcome measurements with the qualitative exposure indices of the individual [...]