The purpose of this study was to evaluate the cerebrovascular and other related health effcets, due to the exposure of ex-workers to carbon disulfide in the manufacture of rayon.

The study subjects comprised of 453 workers from the rayon manufacturing industry (387 males, 66 females). They were examined with a brain MRI and for other risk factors related to their occupation, such as age, work department, work duration, duration of work cessation, and blood pressure. Laboratory tests were also performed such as blood sugar, hemoglobin, cholesterol, etc. The cumulative exposure levels were calculated as the mean exposure level, per work department, multiplied by the total work duration in months.

75.1% of the subjects were between the ages of 40 and 59 years. 76.0% of the subjects had worked in high exposure departments (e.g., department of spinning and refining etc). 52.5% of the subjects had worked for more than 10 years, and 63.3% of the subjects had ginven up the work (exposure) more than 10 years earlier. The brain MRI findings were normal, a single lacunar infarct, multiple lacunar infarcts (mostly, on subcortex and white matter), and a hemorrhage in 52.5, 8.6, 36.2 and 2.7% respectively. Multiple lacunar infarcts were not related to the cumulative exposure level but in the female workers only, were significantly related to the increasing level of work duration (p<0.05), and in the male workers only, were related to the increased duration of work cessation and age (p<0.01). Abnormal rates of laboratory tests were higher in the multiple lacunar infarcts subjects with hypertension compared to theose with normal brain MRI findings (p<0.01).

The multiple lacunar infarcts of the brain seemed not to be related to the cumulative exposure level but to the low exposure departments, duration of work, duration of work cessation, age and hypertension. This was conducted as a health evaluation on workers from the rayon manufacturing industry who had terminated their exposure to carbon disulfide many years earlier.