title: Changes of median nerve conduction velocity in rayon manufacturing workers: A 6-year cohort study.
abstract: OBJECTIVE
  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 CS2exposure during the follow-up period (ex-exposed workers). MCV and SCV were measured at baseline and followed up. CS2personal exposure concentration was measured two times a year during a 6-year follow-up period and mean (range) CS2exposure 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 (ex-exposed workers) / (unexposed workers) was significantly positive (+0.915, p < 0.01) after adjustment for confounding variables.
  
  
  CONCLUSIONS
  This cohort study showed that 6-year CS2exposure 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 CS2on SCV around a mean exposure level of 4 ppm may be reversible, since it disappeared in the ex-exposed workers after CS2exposure cessation for a mean period of 4.1 years.
authors.affiliation: Department of Preventive Medicine and Public Health, Keio University School of Medicine.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Yoshioka
authors.forename: Toru
authors.initials: T
authors.lastname: Takebayashi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nishiwaki
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Nomiyama
authors.forename: Satoko
authors.initials: S
authors.lastname: Iwasawa
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Sakurai
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Omae
mesh_terms: D000328:Adult; D002246:Carbon Disulfide / Q000009:adverse effects* / Q000032:analysis; D002482:Cellulose / Q000009:adverse effects*; D015331:Cohort Studies; D004784:Environmental Monitoring; D019054:Evoked Potentials, Motor; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000187:drug effects*; D009431:Neural Conduction / Q000187:drug effects*; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D012044:Regression Analysis; D011984:Sensory Receptor Cells / Q000187:drug effects*; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D002482:Cellulose; C012024:rayon, purified; D002246:Carbon Disulfide