Coronary heart disease among workers exposed to carbon disulphide.

313-325. Coronary morbidity and some coronary risk factors were studied among workers in a viscose rayon plant. All men with at least five years' exposure to carbon disulphide during any period between 1942 and 1967 were included. In all, 410 men complied with these criteria. Of them, 45 had died and no information was obtained for nine. Three hundred and forty three men attended the examination which included, among other things, electrocardiography after a standardized exercise test, measurement of blood pressure, and a chest radiograph. The concentration of CS and HS had been regularly measured by the plant laboratory from 10 to 40 different sites since 1950. In all, some 3 000 measurements were available. The concentrations have probably been very high in the 1940s, about 20 to 40 ppm in the 1950s, and about 10 to 30 ppm in the 1960s. The exposed men were individually matched with controls from a paper mill, situated in the same city. Age, birth district, and similarity of work were taken into account in the matching. Smoking habits, leisure time physical activity, physical fitness, obesity, and drug therapy were checked at the examination; no practically important differences were found. Comparisons were made for the whole group, for spinners, for those exposed for 15 years or more, and for those with an exposure index (sum of products of duration and intensity of exposure) of more than the mean value of the whole group. The exposed subjects had higher mean systolic and diastolic blood pressures in all comparisons. The differences were statistically significant. The frequency of a history of angina was slightly higher among the exposed subjects; this difference also was statistically significant. A history of infarction was slightly more frequent in the control group, but the difference was not statistically significant. Although the commonly used limits for statistical significance were not achieved for any isolated electrocardiographic finding, classified according to the Minnesota code, there was a slightly higher prevalence of several pathological findings ascribable to coronary heart disease in the exposed group. An excess of coronary deaths was observed for 48 men who had been exposed for at least five years and who had died under 65 years of age. The expected number was 15·2, while the observed number was 25: the difference was statistically significant (P < 0·002). Although no define evidence was found, the excess of coronary deaths in combination with the small hint of a higher prevalence of pathological electrocardiograms among the exposed subjects suggest that CS may be an aetiological factor in the pathogenesis of coronary heart disease.