Some animal studies and some human studies suggest that exposure to
2,3,7,8-tetrachlorodibenzo-p-dioxin (
TCDD) may be associated with adverse effects on the cardiovascular system. As part of a cross-sectional medical study comparing workers employed 15 years earlier in the manufacture of
2,4,5-trichlorophenol or one of its derivatives at two U.S. chemical plants with an unexposed comparison group, we examined the association between
TCDD exposure and various cardiovascular outcomes. A total of 281 workers and 260 unexposed referents participated. The workers had substantial exposure to
TCDD, as demonstrated by significantly elevated mean serum
TCDD concentration of 220 pg/g of
lipid, compared with 7 pg/g of
lipid among the referents. No significant association was found between
TCDD exposure and any of the cardiovascular outcomes including
myocardial infarction, angina,
cardiac arrhythmias,
hypertension, and abnormal peripheral arterial flow. Although our study had sufficient statistical power to detect an elevated risk for
cardiac arrhythmias,
hypertension, and abnormal peripheral arterial
flow, it had low power (approximately 50%) to detect an elevated risk for
myocardial infarction and angina. Our review of the literature suggests that our negative findings are consistent with those from other cross-sectional medical studies. Although several mortality studies of
TCDD-exposed cohorts found significantly increased risks for
cardiovascular disease mortality, similar increased risks were not observed in other mortality 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.