Neurobehavioral disturbances arising from occupational toluene exposure

Abstract

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.