Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam (hereafter referred to as VAO). The work of later committees resulted in the publication of biennial updates (Update 1996, Update 1998, Update 2000, Update 2002, and Update 2004) and of focused reports on the scientific evidence regarding type 2 diabetes, acute myelogenous leukemia in children, and the latent period for respiratory cancer.

This seventh VAO report is the first in a second decade of biennial updates, to continue through 2014, mandated by PL 107-103, the Veterans Education and Benefits Expansion Act of 2001. It presents the current committee’s review of recent scientific publications concerning associations between health outcomes and exposure to TCDD and other chemicals in herbicides used in Vietnam and the committee’s integration of this information with the previously established evidentiary database.


In accordance with PL 102-4 and PL 107-103, the Committee to Review the Health Effects in Vietnam Veterans of Exposure to Herbicides (Sixth Biennial Update) was asked to “determine (to the extent that available scientific data permit meaningful determinations)” the following regarding associations between specific health outcomes and exposure to TCDD and other chemicals in herbicides:

  1. whether a statistical association with herbicide exposure exists, taking into account the strength of the scientific evidence and the appropriateness of the statistical and epidemiological methods used to detect the association;

  2. the increased risk of disease among those exposed to herbicides during service in the Republic of Vietnam during the Vietnam era; and

  3. whether there exists a plausible biological mechanism or other evidence of a causal relationship between herbicide exposure and the disease.

The committee notes that both its congressional mandate and its statement of task are phrased in such a way that the target of evaluation is “association,” not “causality,” between exposure and health outcomes. As used technically, the criteria for causation are somewhat more stringent than those for association. This target was not the choice of VAO committees but the consequence of congressional and judicial history. IOM has recently convened a separate committee to evaluate the methods of the Department of Veterans Affairs (VA) for determining whether medical conditions are service-related; that committee will address this and other issues.

In conducting its study, the present committee operated independently of VA and other government agencies. The committee was not asked to make and did not make judgments regarding specific cases in which individual Vietnam veter-

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