Investigation on neurotoxicity of occupational exposure to cyclohexane: a neurophysiological study

• Published in: Occupational and environmental medicine (London, England) Vol. 53; no. 3; pp. 174 - 179
• Main Authors: Yuasa, J, Kishi, R, Eguchi, T, Harabuchi, I, Kawai, T, Ikeda, M, Sugimoto, R, Matsumoto, H, Miyake, H
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.03.1996; BMJ Publishing Group; BMJ; BMJ Publishing Group LTD
• Subjects: Adult; Air sampling; Biological and medical sciences; Case-Control Studies; Chemical and industrial products toxicology. Toxic occupational diseases; Chemical hazards; Cyclohexanes - adverse effects; Cyclohexanes - urine; Cyclohexanols - urine; Follow up studies; Hexanes; Humans; Medical sciences; Metabolites; Middle Aged; Motor ability; Nerves; Neural Conduction - drug effects; Neurophysiology; Neurotoxicity; Occupational exposure; Occupational Exposure - adverse effects; Peripheral Nerves - drug effects; Peripheral Nerves - physiopathology; Peripheral Nervous System Diseases - chemically induced; Skin temperature; Solvents; Toxicology; Ulnar nerve; Asia; Japan; Human; Peripheral nervous system; Organic solvent; Nervous system diseases; Toxicity; Cyclohexane; Neuropsychological test; Occupational exposure; Epidemiology; Occupational medicine
• ISSN: 1351-0711; 1470-7926
• DOI: 10.1136/oem.53.3.174

OBJECTIVES: To examine the effect of occupational exposure to cyclohexane on the peripheral nervous system. METHODS: A nerve conduction study was performed on 18 workers exposed to cyclohexane in a luggage factory and on age and sex matched occupationally unexposed controls. 12 workers had been exposed to n-hexane (median 2.8 years) before the start of exposure to cyclohexane. To confirm the effect of exposure, a follow up study was performed on nine workers one year after the first study. The mean exposure to cyclohexane was 1.2 years in the first study. A symptom survey was performed. The exposure was measured by air sampling of the breathing zone of each worker. The urinary metabolite cyclohexanol was also monitored. RESULTS: The concentration of airborne cyclohexane ranged from 5 to 211 ppm. The urinary concentration of cyclohexanol ranged from 0.12 to 1.51 mg/l. There was a strong correlation between the cyclohexane exposure in personal air and urinary cyclohexanol. No differences were found in nerve conduction velocities (NCV) between workers exposed to cyclohexane and age and sex matched controls. The results of the follow up study showed significant improvements in peroneal motor NCV (P < 0.01) and sural sensory NCV (P < 0.05) and in ulnar motor distal latency (MDL, P < 0.05) and peroneal MDL (P < 0.05) compared with the first study. Although the past n-hexane exposure affected the first neurophysiological study, the effect had disappeared in the second study, one year later. CONCLUSION: Occupational exposure to the concentrations of cyclohexane experienced in this study had no adverse effects on the peripheral nervous system.