Open AccessChanges of median nerve conduction velocity in rayon manufacturing workers: A 6‐year cohort study
Author(s) -
Yoshioka Noriyuki,
Takebayashi Toru,
Nishiwaki Yuji,
Nomiyama Tetsuo,
Iwasawa Satoko,
Sakurai Haruhiko,
Omae Kazuyuki
Publication year - 2017
Publication title -
journal of occupational health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 59
ISSN - 1348-9585
DOI - 10.1539/joh.16-0255-oa
Subject(s) - medicine , cohort , confounding , cohort study , occupational exposure , nerve conduction , nerve conduction velocity , zoology , environmental health , biology
Objectives We conducted a 6‐year cohort study to evaluate the relationship between carbon disulfide (CS2) exposure and reductions in the motor and sensory nerve conduction velocity (MCV and SCV) of the median nerve. Methods Study subjects at baseline included 432 exposed workers and 402 unexposed workers. Among the exposed workers, 145 workers terminated CS2 exposure during the followup period (ex‐exposed workers). MCV and SCV were measured at baseline and followed up. CS 2 personal exposure concentration was measured two times a year during a 6‐year follow‐up period and mean (range) CS2 exposure concentrations (ppm) were 5.96 (0.8‐16.0) and 3.93 (0.6‐9.9) in the exposed and ex‐exposed workers, respectively. Results Reductions in MCV during the follow‐up period did not differ among the exposed, ex‐exposed, and unexposed workers. Reduction in SCV (m/s) of the exposed workers (‐4.47±3.94) was significantly larger than that of the unexposed (‐3.38±3.97) and ex‐exposed workers (‐3.26±3.79). For SCV reduction, a partial multiple regression coefficient of (exexposed workers)/(unexposed workers) was significantly positive (+0.915, p < 0.01) after adjustment for confounding variables. Conclusions This cohort study showed that 6‐year CS 2 exposure around a mean level of 6 ppm did not affect MCV reduction but induced significant SCV reduction beyond the influence of aging. The effect of CS2 on SCV around a mean exposure level of 4 ppm may be reversible, since it disappeared in the ex‐exposed workers after CS 2 exposure cessation for a mean period of 4.1 years.