Thursday April 19, 2001 3:56 PM ET
By Sue Pleming
WASHINGTON (Reuters) - There may be a link between the dioxin-laced herbicide Agent Orange, sprayed widely in the Vietnam War, and a form of childhood leukemia found in veterans' children, said an official report released on Thursday.
The Institute of Medicine (news - web sites) of the National Academies, an independent research body that often advises government, stopped short of establishing a direct connection between the herbicide and leukemia but said there was ``limited or suggestive"" evidence of such a link.
The report, ordered by Congress in response to concerns by Vietnam veterans and their families, reviewed the findings of two studies in particular that looked at the link between acute myelogenous leukemia (AML) in veterans' children and herbicides including Agent Orange.
``No firm evidence links exposure to the herbicides with most childhood cancers but the new research does suggest that some kind of connection exists between AML in children and their fathers' military service in Vietnam or Cambodia,"" said committee chair Irva Hertz-Picciotto, professor of epidemiology at the University of North Carolina, Chapel Hill.
Hertz-Picciotto said additional studies were needed to shed more light on the impact on veterans' children of Agent Orange, named after the striped orange barrels used to transport it.
``What is significant here is that this is a second-generation possible effect of Agent Orange,"" she told Reuters. U.S. forces sprayed some 19 million gallons of herbicides, of which Agent Orange is the best known, over southern Vietnam during the war to deny Communist guerrillas jungle cover.
Hanoi blames Agent Orange for causing tens of thousands of birth defects in Vietnam and has demanded compensation.
The U.S. government has consistently said a link remains to be proven between Agent Orange and hereditary birth defects. A U.S. Air Force study released last year, however, did show a significant link between it and diabetes in veterans.
In the studies on AML, the strongest link was seen in children diagnosed at the youngest ages, a pattern that suggested that the cause of a disease stems from a parent, said Hertz-Picciotto.
A third study found that the development of AML was more likely in the children of men who used pesticides or herbicides in their work, Hertz-Picciotto said.
The evidence in the new report was rated as ``limited or suggestive"" because while there was evidence of a link between exposure and the disease, it was not conclusive enough to say other factors did not influence the results.
Research into the health impact of Agent Orange had been hampered by inadequate information about exposure levels of troops in Vietnam, the report said.
``The research has just not been done in which we can say these people served here and so this is the exposure-level they got,"" said Hertz-Picciotto.
The National Academies was mandated by Congress to conduct two-yearly studies over a decade on the impact of Agent Orange on the health of veterans. The first report was released in 1994 and the final one will be in two years.
Earlier reports found evidence of a link between exposure to herbicides and soft-tissue sarcoma, Hodgkin's disease, non-Hodgkin's lymphoma and chloracne in veterans.
Hertz-Picciotto said additional studies provided ``limited"" evidence of diabetes, respiratory cancers, prostate cancer and multiple myeloma as well as the congenital birth defect spina bifida in veterans' children.
Most widespread sprayings of Agent Orange were conducted from airplanes and helicopters but some of the herbicides were dispersed from boats and ground vehicles or by soldiers wearing back-mounted equipment.
A 1969 study concluded that one of the primary chemicals in Agent Orange could cause birth defects in laboratory animals. The U.S. military suspended the use of Agent Orange in 1970 and halted all herbicide spraying in Vietnam the following year.
A Pentagon (news - web sites) spokeswoman said the defense department would review the latest report before commenting on it.