By Staff Sgt. Kathleen T. Rhem, USA
American Forces Press Service
WASHINGTON, March 29, 2000 -- Adult-onset diabetes in Vietnam vets may be associated with exposure to the herbicide Agent Orange, a Air Force report released today states.
The report is part of the long-running Ranch Hand Study – the Air Force investigation into the health risks associated with exposure to Agent Orange. It also included evidence that herbicide exposure is related to cardiovascular disease later in life. The study is called Ranch Hand because the original mission of spraying Agent Orange in Vietnam was called Operation Ranch Hand.
"This report includes the strongest evidence to date that exposure to Agent Orange is associated with adult-onset diabetes," said Joel Michalek, a statistician with the Air Force Research Lab at Brooks Air Force Base, Texas. Michalek is the principal investigator of the Ranch Hand Study.
The latest results suggest that as dioxin levels increase, the presence and severity of adult-onset diabetes increase, he said. He also said that as dioxin levels increase, the time to onset of the disease decreases. A 47 percent increase in diabetes was seen in those veterans with the highest levels of dioxin.
"This is particularly strong evidence since dioxin is that component of Agent Orange that has been linked to many health effects in laboratory animals," Michalek said.
Michalek said the Ranch Hand veterans experienced a 26 percent increase in heart disease, but the risk was not increased in those with the highest levels of dioxin. However, the risk of cardiovascular abnormalities, such as high blood pressure and the prevalence of prior heart attack indicated by electrocardiogram, did tend to increase with dioxin levels.
"The mixed results mean that some indicators of disease increased with exposure and others did not," he said.
He was careful to point out that while these findings suggested a link between these diseases and Agent Orange exposure, they're not conclusive.
"Biological processes relating herbicide exposure with these diseases have not yet been described," Michalek said. "I'm not prepared to say that dioxin causes diabetes. People who have high dioxin levels are at a greater risk of diabetes."
The Air Force is, however, taking steps to prove cause and effect. The service is funding research at the University of California at Davis and at the Department of Veterans Affairs Medical Center in Little Rock, Ark., to explain any biological relationship between dioxin and diabetes.
The Ranch Hand Study has been going on since 1978 and includes periodic examinations of about 2,300 Vietnam veterans -- 1,000 who worked on Operation Ranch Hand and another 1,300 who flew missions in Vietnam but weren't associated with the operation. This latest release of information is associated with physical exams conducted in 1997.
Previous examinations and reports have suggested links between Agent Orange exposure and nine distinct diseases: chloracne, Hodgkin's disease, multiple myeloma, non-Hodgkin's lymphoma, porphyria cutanea tarda, respiratory cancers (lung, bronchus, larynx and trachea), soft-tissue sarcoma, acute and subacute peripheral neuropathy, and prostate cancer.
In addition, monetary benefits, health care and vocational rehabilitation services are provided to Vietnam veterans' offspring with spina bifida, a congenital birth defect of the spine. VA presumes that all military personnel who served in Vietnam and who have one of the listed diseases were exposed to Agent Orange, and it compensates veterans with any of these diseases. Michalek said any future decisions to compensate veterans with diabetes would be made by the VA.
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