Armed Forces News

Vietnam War Defoliation Mission: A UH-1D helicopter from the 336th Aviation Company sprays Agent Orange on a dense jungle area in the Mekong delta.

Vietnam War veterans who suffer from hypertension may have contracted the condition when they were exposed to the chemical defoliant Agent Orange. A Nov. 14 report by the National Academies or Sciences, Engineering and Medicine found “sufficient evidence” that the malady and Agent Orange exposure are linked. The report also cited another related condition – monoclonal gammopathy of undetermined significance (MGUS).

Researchers have long suspected that Agent Orange exposure is a likely cause of hypertension (high blood pressure that can lead to severe health consequences). According to the report, though, new findings show that there is “sufficient” evidence of a connection – an upgrade from the previous “limited or suggestive” category.


The researchers based their conclusion upon studies of veterans conducted by the Department of Veterans Affairs, which indicated high incidences of hypertension among military personnel who served during the Vietnam War era who had “the greatest opportunity for exposure to these chemicals. Additionally, they determined that “sufficient evidence” exists to link exposure to MGUS, a condition that could be a precursor to multiple myeloma, a form of cancer.

The researchers also looked for a link between exposure and Type 2 diabetes, but could not conclude that there is sufficient evidence to support such a conclusion.

U.S. troops used Agent Orange and other herbicides extensively from 1962 to 1971, to eliminate the jungle canopy in Vietnam and expose enemy positions. As a result, anywhere from 2.6 million to 4.3 million troops were exposed to these highly toxic chemicals.

Researchers at the academies have conducted periodic, VA-sponsored studies of epidemiology related to wartime defoliant exposure. They concluded that while progress has been made in linking chemical exposure to illness, more work needs to be done.

“Significant gaps in knowledge remain,” they wrote.

Their recommendations include more “toxicologic, mechanist, and epidemiologic research. There are many questions regarding veterans’ health that can only be adequately answered by examining veterans themselves, thereby properly accounting for the totality of the military service experience.”