Scientists roll back on Agent Orange - cancer link
WASHINGTON - Scientists who advise the U.S. government rescinded a report this week that had linked Agent Orange, used to strip jungles during the Vietnam War, with childhood leukemia.
The revised Institute of Medicine report says there is not enough evidence to say whether children of Vietnam veterans have a higher risk of acute myelogenous leukemia (AML), a deadly blood cancer.
\"On the whole, there is insufficient evidence at this time to determine whether a connection exists between AML in children and their parents\' military service in Vietnam or Cambodia,\" Irva Hertz-Picciotto, a professor of epidemiology at the University of California Davis who chaired the panel, said in a statement.
Less than a year ago, in April 2001, the institute reported that there was a probable link between AML in children and their parents\' exposure to Agent Orange, a herbicide that contains the known carcinogen dioxin, in Vietnam.
But a few months later, Australian researchers whose study was key to the institute\'s report said they had made substantial errors. After correcting for faulty data, the Australian study no longer showed that children of Australia\'s Vietnam veterans faced a greater risk of AML.
U.S. Secretary of Veterans Affairs Anthony Principi asked the institute, one of the National Academies of Sciences, to re-evaluate.
\"The committee also considered new evidence from German and Norwegian studies of AML in the offspring of parents who had occupational exposure to pesticides,\" the institute said in a statement.
\"Neither study found a significant difference in incidence from unexposed populations.\"
LEUKEMIA LINK STILL POSSIBLE
The report said it was possible that Agent Orange exposure did increase the risk of AML. \"Studies of both U.S and Australian veterans reported a slightly elevated incidence of the disease in offspring,\" the report said.
But the reports do not go into enough detail to be persuasive, the 10-member expert committee decided.
At least 9 million gallons of Agent Orange was sprayed on Vietnam between 1962 and 1970. The chemical got its nickname from the orange stripe on the barrels in which it came.
It has been linked with 10 diseases, including lung cancer, prostate cancer and diabetes.
Government officials estimate that between 500 and 1,000 children of Vietnam veterans have or had AML. The American Cancer Society projects that 2,700 children under the age of 15 were diagnosed with leukemia in 2001, about 700 of them AML.
Some studies have suggested that when mothers or fathers are exposed to pesticides, and perhaps when mothers are exposed to marijuana or ethanol during pregnancy, the child has a higher risk of AML.
Vietnam\'s government blames Agent Orange for causing tens of thousands of birth defects in Vietnam and has demanded compensation.
After Agent Orange was found to cause cancer in laboratory rats, the U.S. military suspended its use in 1970 and halted all herbicide spraying in Vietnam the following year.
Story by Maggie Fox, Health and Science Correspondent
REUTERS NEWS SERVICE
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