Introduction and objective:

toluene is an organic solvent derived from benzene used in various industries, with potential harmful effects for workers. This study aims to determine the possible neurological effects of workers exposed to toluene.

Material and methods:

Systematic review of studies published in English and Spanish between January/2000-December/2021. The databases consulted were MEDLINE, WOS, Scopus, Embase, LILACS, IBECS and Cochrane Library. Study quality was assessed using the STROBE statement and the level of evidence using the SIGN criteria.

Results:

14 observational studies were included (quality between 13-18, level of evidence between 2+ and 3). Eight studies examined non-specific neurological symptoms and behavioral alterations, finding an increase in symptoms such as headache, nausea or vomiting, and a decrease in motor performance and attention in workers exposed to toluene (p<0.05). Four studies examined visual effects, finding higher Color Confusion Index (CCI) values in the exposed group (p<0.05). Finally, two studies examined the effects of toluene on hearing in co-exposure with noise observing in one of them aggravation of hearing loss in noisy environment (mean concentration 33-164.6ppm), (p<0.001); while in the other study no effects were observed at concentrations ≤50ppm.

Conclusion:

occupational exposure to toluene produces neurological effects such as nonspecific symptoms, behavioral alterations, and effects on vision and hearing. However, it is necessary to carry out studies with better design and methodological quality, adjusting for confounding factors and with a larger sample size.