Psychomotor performance and subjective symptoms at low level toluene exposure

Possible effects of long term occupational exposure to toluene below the level of 100 ppm on psychomotor performance and subjective symptoms were investigated in a cross sectional approach.

From German rotogravure printing plants 278 male workers, mean age 39.8 years, mean duration of employment 14.9 years, were examined. A mean lifetime weighted average exposure (LWAE) of 45.1 ppm toluene in ambient air was found for 154 exposed workers (rotogravure printing area), with a mean current exposure of 24.7 ppm. The corresponding data for a second group of 124 workers with very low exposure (endprocessing area) had LWAE of 9.3 ppm and a current exposure of 3.3 ppm toluene. Psychomotor performance (steadiness, line tracing, aiming, tapping, and peg board) and subjective symptoms were examined.

No significant differences between the two exposure groups were found by analysis of variance (ANOVA). By stepwise linear regression analyses there were weak associations of LWAE with one performance variable and two symptoms scales, but the results were not significant after correction for the alpha error. Psychomotor performance was mostly affected by age (maximum explained variance up to 13%), and handedness (up to 9%), whereas subjective symptoms are mostly affected by anxiety (up to 38%).

The weak associations between long term exposure to toluene should be used to indicate further longitudinal investigations. The results of this cross sectional study show no obvious dose response relation for psychomotor functions and subjective symptoms among workers exposed to toluene at a current exposure level of 1-88 ppm.