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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.

The purpose of this study was to establish a basis for the use of a device for measuring vibrotactile perception thresholds for epidemiological purposes on a series of non-exposed populations. Vibrotactile perception thresholds (VPTs) were measured with a vibrometer in 218 men and 160 women belonging to two non-exposed male blue collar populations, one white-collar population and one age and gender stratified sample of the general population. VPTs were measured on the middle and the little finger of the dominant hand at 31.5 and 125 Hz. The VPTs were expressed in dB and the effect of a series of factors including the population, age, gender and digital temperature was assessed in a regression analysis weighted by the inverse variance of the measurements. Adjusted for age, no significant difference between the VPTs in the four male populations was observed. At frequency 125 Hz, the effect of age (0.3 dB per year) was more important than at frequency 31.5 Hz (0.2 dB per year). In the two female populations, the results were less stable than among males and the VPTs were higher than among males. However, the age-dependence was similar among males and females. The within-test variance is a valuable indicator of the quality of the VPT measurements. Weighting by its inverse improved the fit of the regression models. Normal values for VPTs in non-exposed populations were obtained, which were reproducible in four separate populations.

Pour étudier les effets ototoxiques des solvants industriels dans le cadre d’études épidémiologiques, il faut disposer de tests audiologiques adaptés. Cette adaptation doit tenir compte de plusieurs contraintes: les tests doivent pouvoir déterminer les niveaux lésionnels liés au processus ototoxique incriminé, ils doivent répondre à des critères de qualité nécessaires aux études épidémiologiques en général (reproductibilité et sensibilité), et tenir compte de l’environnement dans lequel ils seront effectués, en entreprise, auprès de salariés a priori asymptomatiques. Deux batteries audiologiques font référence, ce sont celles mises au point par les équipes suédoises d’Odkvist et de Johnson. Elles utilisent un matériel vocal adéquat qui n’est pas disponible en français. Les auteurs ont donc choisi de développer une batterie en langue française, comparable aux batteries de référence existantes tout en respectant les contraintes de pertinence et de qualité des tests, de faisabilité en entreprises et en utilisant le matériel vocal français disponible. La batterie en langue française proposée ici comprend l’audiométrie tonale liminaire selon la technique d’Hughson Westlake, l’audiométrie vocale dans le bruit selon la méthode d’interpolation d’Hagerman, l’audiométrie vocale à interruptions périodiques adaptée avec listes de Fournier, la recherche des réflexes stapédiens et l’étude des produits de distorsion.

Poster; International audience

Neurotoxicity of long-term exposure to toluene is known at higher levels than 50 ppm and is suspected at lower levels.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.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.In this study, low present exposure levels to toluene were associated with decrements of memory test performances.

National audience

Poster; International audience