Skip to main content

Currently Skimming:

Summary
Pages 1-13

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 1...
... Complaints from returning Vietnam veterans about their own health and that of their children, combined with emerging toxicologic evidence of adverse effects of phenoxy herbicides and TCDD from animal studies and some positive findings from epidemiologic studies, resulted in sustained controversy. In 1991, because of continuing uncertainty about long-term health effects of the sprayed herbicides in Vietnam veterans, Congress passed Public Law (PL)
From page 2...
... " the following regarding associations between specific health outcomes and exposure to TCDD and other chemicals in herbicides used by the military in Vietnam: A)  hether a statistical association with herbicide exposure exists, taking w into account the strength of the scientific evidence and the appropriate ness of the statistical and epidemiological methods used to detect the association; B)
From page 3...
... , the committee remains neutral, abiding by the maxim that "absence of evidence is not evidence of absence." In accord with Congress's mandated presumption of herbicide exposure of all Vietnam veterans, VAO committees have treated Vietnam-veteran status as a proxy for some herbicide exposure when no more specific exposure information
From page 4...
... , a continuing prospective cohort study of agricultural populations with specific information on the chemicals of interest, is also steadily contributing new findings to the database. The Vietnam veterans themselves are advancing in age and, when studied, are capable of providing substantial information on chronic health conditions directly; however, the intensity of research on this target population has waned in recent years.
From page 5...
... The committee recognizes that an absolute conclusion about the absence of association might never be attained because, as is generally the case in science, studies of health outcomes after herbicide exposure cannot demonstrate that a purported outcome is impossible, only that it is statistically improbable. EVIDENCE REVIEWED BY THE COMMITTEE The sections below summarize new epidemiologic information evaluated in this update and integrated with that previously assembled.
From page 6...
... Plasma dioxin concentrations and cause-specific mortality were investigated in German production workers in a plant included in the IARC cohort in Hamburg, Germany, and three new studies of IARC subcohorts in the Netherlands reported on cancer mortality, ischemic heart disease, humoral immunity, atopic disease, and immune suppression in herbicide workers. An examination of pesticide appliers and gliomas in participants in the Upper Midwest Health Study was reviewed, and eight recent reports from the AHS examined cancer incidence, body-mass index, amyotrophic lateral sclerosis, and mortality in private pesticide applicators (farmers)
From page 7...
... THE COMMITTEE'S CONCLUSIONS Health Outcomes In Update 2012, the committee has elected to change the categorization of one health outcome listed in Table S-1. The committee voted unanimously to move stroke to the "limited and suggestive" category because of new evidence showing a statistically significant association in the well-designed PIVUS study; evidence of an overall increase in stroke and cerebrovascular disease associated with exposure to the chemicals of interest in environmental, occupational, and Vietnam-veteran populations in the most relevant of previously considered studies; demonstrated biological plausibility from human and animal studies; and the strong connection between stroke and hypertension, cardiovascular disease, and diabetes (three conditions already in the limited and suggestive category)
From page 8...
... Spina bifida in offspring of exposed people Inadequate or Insufficient Evidence to Determine an Association The available epidemiologic studies are of insufficient quality, consistency, or statistical power to permit a conclusion regarding the presence or absence of an association. For example, studies fail to control for confounding, have inadequate exposure assessment, or fail to address latency.
From page 9...
... By default, any health outcome on which no epidemiologic information has been found falls into this category. Limited or Suggestive Evidence of No Association Several adequate studies, which cover the full range of human exposure, are consistent in not showing a positive association between any magnitude of exposure to a component of the continued
From page 10...
... Table S-1 defines four categories of association and gives criteria for assigning health outcomes to them. (Although the committee for this update did not modify the criteria used by previous VAO committees for assigning categories of association to health outcomes, it has inserted "scientifically relevant" before "association" in the title of Table S-1 to clarify that the strength of evidence evaluated, based on the quality of the scientific studies reviewed, was a fundamental component of the committee's deliberations to address the imprecisely defined legislative target of "statistical association.")
From page 11...
... In light of those problems, many conclusions regarding associations between exposure to the chemicals of interest and disease have been based on studies of people exposed in various occupational and environmental settings rather than on studies of Vietnam veterans, although more recent studies of health consequences in the maturing veterans themselves have generated more informative findings than originally available to VAO committees. The committee believes that there is sufficient evidence to reach general or qualitative conclusions about associations between herbicide exposure and health outcomes, but the lack of adequate exposure data on Vietnam veterans themselves makes it difficult to estimate the degree of increased risk of disease in Vietnam veterans as a group or individually.
From page 12...
... This committee recommends that VA query its own medical databases more actively to identify potential associations between Vietnam service and specific health outcomes, particularly outcomes that are so common or so specific that they are infrequently addressed in epidemiology studies. Moreover, if a perceived conflict of interest exists in surveying its own databases, it is recommended that an external advisory group be formed to determine the best mechanism for mining the information so that these medical databases can be available for external study.
From page 13...
... Longitudinal analyses of cancer, cardiovascular, and reproductive outcomes represented in the complete database assembled in the course of the AFHS are especially important. The committee is encouraged that VA has reinitiated the National Vietnam Veterans Longitudinal Study and has launched the Army Chemical Corps Vietnam-Era Veterans Health study to investigate the relationship of herbicide exposure during the Vietnam War with hypertension and COPD in ACC veterans.


This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More information on Chapter Skim is available.