EVALUATION OF CARDIOVASCULAR OUTCOMES AMONG US WORKERS EXPOSED TO 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN

Some animal studies and some human studies suggest that exposure to 2, 3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) may be associated with advers e effects on the cardiovascular system. As part of a cross-sectional m edical study comparing workers employed 15 years earlier in the manufa cture of 2,4,5-trichlorophenol or one of its derivatives at two U.S. c hemical plants with an unexposed comparison group, we examined the ass ociation between TCDD exposure and various cardiovascular outcomes. A total of 281 workers and 260 unexposed referents participated. The wor kers had substantial exposure to TCDD, as demonstrated by significantl y elevated mean serum TCDD concentration of 220 pg/g of lipid, compare d with 7 pg/g of lipid among the referents. No significant association was found between TCDD exposure and any of the cardiovascular outcome s including myocardial infarction, angina, cardiac arrhythmias, hypert ension, and abnormal peripheral arterial flow. Although our study had sufficient statistical power to detect an elevated risk for cardiac ar rhythmias, hypertension, and abnormal peripheral arterial flow, it had low power (approximately 50%) to detect an elevated risk for myocardi al infarction and angina. Our review of the literature suggests that o ur negative findings are consistent with those from other cross-sectio nal medical studies. Although several mortality studies of TCDD-expose d cohorts found significantly increased risks for cardiovascular disea se mortality, similar increased risks were not observed in other morta lity studies. The data available do not provide definitive conclusions but indicate that further examination of the association between TCDD exposure and cardiovascular disease should be pursued.