MORTALITY AMONG WORKERS EXPOSED TO CARBON-DISULFIDE

Mortality experience was investigated at a plant in Ontario that produ ced viscose rayon, with carbon disulfide as a main raw material. Work- history records for 279 deceased workers at the plant (plant A) were o btained and compared with those for 511 deceased workers at a pulp and paper plant in the same city (plant B). In a proportional mortality a nalysis, using as a reference the general population of Ontario, at bo th plants there were fewer deaths from ischemic heart disease than exp ected (the proportional mortality ratios [PMRs] were 83 at plant A and 95 at plant B) but more deaths than expected from cerebrovascular dis ease (PMRs were 115 at plant A and 149 at plant B). In a subgroup of p lant A workers who had been employed in high-carbon-disulfide exposure areas, deaths from ischemic heart disease were less than expected (PM R = 82), particularly among those who worked in these areas for more t han 5 y. Most deaths occurred among those aged 65 y or more. Mortality from strokes, however, was greater than expected (PMR = 207, p < .05) ; the excess was confined to workers who died at age 65 y or older (PM R = 229, p .01). Proportional mortality from strokes was also increase d in the pulp workers among those who died at age 65 y or older (PMR = 153). In a case-control analysis, the risk of ischemic heart disease at plant A was slightly less than at plant B (odds ratio [OR] = 0.92, 95% confidence interval [Cl] = 0.60-1.42), with no association between risk and years worked in high-carbon-disulfide areas (OR/y = 0.99, 95 % Cl = 0.94-1.03). Among those who died at age 65 y or older, the risk of stroke in the high-exposure subgroup was (a) increased significant ly, compared with other plant A workers (OR = 4.92, 95% Cl 1.66-14.65) ; and (b) increased slightly, compared with plant B workers (OR = 1.37 , 95% Cl = 0.83-2.26). These results suggested an unusually low risk o f strokes among other plant A workers. The risk of stroke was associat ed with years in high-carbon-disulfide areas (OR/y = 1.03, 95% Cl = 0. 96-1.10). The observed increase in proportional mortality from strokes may represent a chance finding, but a causal role for exposure cannot be excluded.