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Agent Orange Doubles the Risk of Dementia for Vietnam Veterans

Friday, August 13th, 2021

U.S. veterans exposed to Agent Orange during the Vietnam War are twice as likely to develop dementia, a study published early this year found[1].

Tactical Warfare

U.S. forces sprayed gallons of Agent Orange during the Vietnam War to defoliate jungle trees that provided cover for enemy forces, and to destroy food crops. Millions of American servicemen were exposed to the herbicide. Its active ingredient, dioxin, may persist in fat tissues in the body for decades.

A Large Cohort Study

The American research team reviewed the electronic medical records of a random selection of 2% of veterans who served during the Vietnam War and who received care through the Veterans Health Administration between 2001 and 2015. The researchers analysed data on 316,351 vets of the initial 511,189 eligible participants. They excluded anyone already diagnosed with dementia, those without follow-up visits, and those whose Agent Orange exposure was unclear.

The veterans were almost all male (98 percent) and were on average 62 years old when the study began. Participants were deemed to have been exposed to Agent Orange if they reported having served in Vietnam and had exposure and a clinician indicated that a health encounter was related to Agent Orange exposure. A total of 38,121 veterans (12.1 percent) reported exposure to Agent Orange.

Double Dementia Risk

The researchers found that veterans exposed to the herbicide were nearly twice as likely to develop dementia than their veteran peers who had not been exposed – specifically, five versus 2.5 percent. Whilst veterans with a history of Agent Orange exposure were more likely to have post-traumatic stress disorder or traumatic brain injury in their medical records, even after adjusting for these and other factors that can play a role in dementia development, the two-fold risk remained. The research also discovered that among those who developed dementia, the exposed vets were more likely to be diagnosed at a younger age than non-exposed vets- 67.5 years versus 68.8 years.

A Link but not Causation

The study showed only a link between dementia and the herbicide. The findings do not prove cause and effect. The researchers are not sure why Agent Orange might increase dementia risk. One possibility is that the active ingredient dioxin might interrupt hormones and brain neurotransmitters. It also increases the likelihood of other disorders that themselves are risk factors for dementia, thus it could be that dioxin has in indirect effect on risk.

Remaining Vigilant

The study did not include veterans who received care outside of the Veterans Health Administration. Nor did the study contain any baseline cognitive scores, which might have revealed whether any of the veterans had undiagnosed dementia at the study start. Many factors can contribute to who gets dementia, including genetics, diet, education, and exercise levels. Still, the findings suggest that Vietnam veterans who were exposed to Agent Orange might want to be extra vigilant about early signs of cognitive issues. Engaging in a healthier lifestyle could also help offset any risk.