Cancer and heart risks of dioxins.

Several studies have indicated an apparent increased risk of death from cancer among individuals heavily exposed to dioxins and such close chemical cousins as furans (SN: 9/4/93, p.149). A new study now looks at men who worked at a pesticide plant in Hamburg, Germany, at any time between 1952 and the facility's closing in 1984. It shows that a man's exposure to dioxins and furans corresponds to a dose-dependent elevation in his risk of dying not only from cancer but also from heart disease-especially clogged arteries.

Dieter Flesch-Janys of Hamburg's Center for Chemical Workers' Health and his colleagues stratified the 1,189 men using estimates of each worker's exposure. They based those values on how long a man had worked (and where in the plant) and, if available, on recorded body concentrations of TCDD-the most potent dioxin-or its toxic equivalents. They found that plant veterans with the highest exposures faced more than three times the risk of dying from cancer and 2.5 times the risk of dying from ischemic heart disease as workers of similar ages from a nearby gas plant.

"These findings refine the strong existing evidence of a carcinogenic effect of [dioxins and furans] in humans," the researchers conclude in the Dec. 1 American Journal of Epidemiology. The Hamburg team cites three reports that showed hints of a heart disease risk attributable to dioxins. In one of these reports, the investigating epidemiologists had speculated that stress was the likely cause. In their new study, Flesch-Janys and his coworkers note that "there is some evidence from animal models that TCDD may promote atherosclerosis," which "lends credibility to a causal interpretation of our [heart disease] findings."