Neurobehavioral disturbances arising from occupational toluene exposure

Background Neurotoxicity of long-term exposure to toluene is known at higher levels than 50 ppm and is suspected at lower levels. Methods A cross-sectional study carried out in two printing plants on 129 blue collar workers explored such a low level exposure of toluene. With 231 samples of ambient air, toluene concentration was estimated from 0 to 18 ppm in Plant A (offset) and from 2 to 27 ppm in Plant B (heliogravure). Outside any period of acute exposure, the workers answered a self-administered questionnaire on neurotoxic symptoms, EUROQUEST, and performed six psychometric tests on a computer-assisted version of battery NES. Results After adjustment for confounders, we found significant relationships only between present exposure and Digit Span Forwards (DSF) performance (decrement is 1 digit for 40 ppm, P = 0.04) and Digit Span Backwards (DSB) performance (decrement is 1 digit for 25 ppm, P = 0.01). Neurotoxic symptoms were not significantly correlated with current exposure. No association was found between estimated cumulative exposure and either psychometric performances or neurotoxic symptoms. Conclusion In this study, low present exposure levels to toluene were associated with decrements of memory test performances. Am. J. Ind. Med. 41:77–88, 2002. © 2002 Wiley-Liss, Inc.