Department of Veterans Affairs.
As required by law, the Department of Veterans Affairs (VA) hereby gives notice that the Secretary of Veterans Affairs, under the authority granted by the Persian Gulf War Veterans Act of 1998, Public Law 105-277, title XVI, 112 Stat. 2681-742 through 2681-749 (codified in part at 38 U.S.C. 1118), has determined that there is no basis to establish a presumption of service connection for any of the diseases, illnesses, or health effects discussed in the August 2004 report of the National Academy of Sciences, titled “Gulf War and Health: Updated Literature Review of Sarin,” based on exposure to sarin during service in the Persian Gulf during the Persian Gulf War.Start Further Info
FOR FURTHER INFORMATION CONTACT:
Maya Ferrandino, Regulations Staff (211D), Compensation and Pension Service, Veterans Benefits Administration, Department of Veterans Affairs, 810 Vermont Avenue, NW., Washington, DC 20420, (727) 319-5847.End Further Info End Preamble Start Supplemental Information
I. Statutory Requirements
The Persian Gulf War Veterans Act of 1998, Public Law 105-277, title XVI, 112 Stat. 2681-742 through 2681-749 (codified in part at 38 U.S.C. 1118), and the Veterans Programs Enhancement Act of 1998, Public Law 105-368, 112 Stat. 3315, directed the Secretary to seek to enter into an agreement with the National Academy of Sciences (NAS) to review and evaluate the available scientific evidence regarding associations between illnesses and exposure to toxic agents, environmental or wartime hazards, or preventive medicines or vaccines to which service members may have been exposed during service in the Persian Gulf during the Persian Gulf War. Congress directed NAS to identify agents, hazards, Start Printed Page 42412medicines, and vaccines to which service members may have been exposed during service in the Persian Gulf during the Persian Gulf War.
Congress mandated that NAS determine, to the extent possible: (1) Whether there is a statistical association between exposure to the agent, hazard, medicine, or vaccine and the illness, taking into account the strength of the scientific evidence and the appropriateness of the scientific methodology used to detect the association; (2) the increased risk of illness among individuals exposed to the agent, hazard, medicine, or vaccine; and (3) whether a plausible biological mechanism or other evidence of a causal relationship exists between exposure to the agent, hazard, medicine, or vaccine, and the illness.
Section 1602 of Public Law 105-277 provides that whenever the Secretary determines, based on sound medical and scientific evidence, that a positive association (i.e., the credible evidence for the association is equal to or outweighs the credible evidence against the association) exists between exposure of humans or animals to a biological, chemical, or other toxic agent, environmental or wartime hazard, or preventive medicine or vaccine known or presumed to be associated with service in the Southwest Asia theater of operations during the Persian Gulf War and the occurrence of a diagnosed or undiagnosed illness in humans or animals, the Secretary will publish regulations establishing presumptive service connection for that illness. If the Secretary determines that a presumption of service connection is not warranted, he is to publish a notice of that determination, including an explanation of the scientific basis for that determination. The Secretary's determination must be based on consideration of the NAS reports and all other sound medical and scientific information and analysis available to the Secretary.
Although Public Law 105-277 does not define “credible evidence,” it does instruct the Secretary to “take into consideration whether the results (of any study) are statistically significant, are capable or replication, and withstand peer review.” Simply comparing the number of studies that report a significantly increased relative risk to the number of studies that report a relative risk that is not significantly increased is not a valid method for determining whether the weight of evidence overall supports a finding that there is or is not a positive association between exposure to an agent, hazard, or medicine or vaccine and the subsequent development of the particular illness. Because of differences in statistical significance, confidence levels, control for confounding factors, and other pertinent characteristics, some studies are clearly more credible than others, and the Secretary has given the more credible studies more weight in evaluating the overall weight of the evidence concerning specific illnesses.
II. NAS Reports on Sarin
NAS issued its initial report titled, Gulf War and Health, Volume 1: Depleted Uranium, Sarin, Pyridostigmine Bromide, Vaccines, on January 1, 2000. In that report, NAS limited its analysis to the health effects of depleted uranium, the chemical warfare agent sarin, vaccinations against botulism toxin and anthrax, and pyridostigmine bromide, which was used in the Gulf War as a pretreatment for possible exposure to nerve agents. On July 6, 2001, VA published a notice in the Federal Register announcing the Secretary's determination that the available evidence did not warrant a presumption of service connection for any disease discussed in that report, including sarin. See 66 FR 35702.
NAS issued a supplemental report, titled “Gulf War and Health: Updated Literature Review on Sarin” in August 2004. In that report, the Committee focused on the health effects associated with exposure to sarin and related compounds, including relevant epidemiologic studies. This Notice addresses the August 2004 Update on sarin.
III. The Committee's Review
In the August 2004 Update on sarin, the Committee reviewed the peer-reviewed literature published since its earlier 2000 report on health effects associated with exposure to sarin and related compounds. These included both animal and human studies. In reviewing published studies, the Committee based its determinations on the strength of the evidence of associations between compound exposure and human health effects as reported in those studies. The Committee also considered other relevant issues, including exposure to multiple chemicals and genetic susceptibilities.
The literature search on sarin and cyclosarin located about 250 articles published after the 2000 report. The Committee relied only on published peer-reviewed articles for their review, although each article was carefully reviewed for its relevance and quality. The Committee relied primarily upon epidemiological studies that involved humans. Animal studies had a lesser role in its assessment of the potential relationship between sarin exposure and health effects, and were used, as in previous NAS studies, primarily for making assessments of biological plausibility in support of epidemiological findings.
The Committee reviewed 19 epidemiological studies of sarin health effects published since its original 2000 report. These included three studies on non-Gulf War veterans, four studies of Gulf War veterans potentially exposed at Khamisiyah, six population-based studies of U.S. and U.K. Gulf War veterans using self-reported exposures, and six studies of specific military units of Gulf War veterans also using self-reported exposures. They also looked again at all of the studies used in the 2000 report. The non-Gulf War veteran studies reviewed in both the 2004 update and the earlier 2000 report were based on U.S. military volunteers who had been exposed several decades ago to non-lethal doses of sarin and other chemical warfare agents; on industrial workers with documented acute exposure to sarin; and on victims of the sarin terrorist attacks in Matsumoto City in 1994 and Tokyo in 1995. The Committee pointed out that a major limitation of virtually all human studies is a lack of good exposure information.
The Committee report pointed to the uncertainties surrounding the Department of Defense (DoD) sarin exposure assessment for Khamisiyah, and how those uncertainties limit the ability of studies that rely upon that modeling data to provide strong evidence for the presence or the absence of any association between sarin exposure and health outcomes. They stated, “none of the studies using exposure information showed persistent neurological effects in Khamisiyah-exposed troops compared to non-Khamisiyah exposed troops. Because of the uncertainty in the exposure assessment models those studies do not provide strong evidence for or against the presence of neurologic effects.” Therefore, the studies based upon the DoD Khamisiyah modeling had little impact on the Committee's findings.
The Committee also reported on new published data regarding experimental animals that were designed to mimic the potential exposures in the Gulf War. These data had precipitated the interest in an updated study of sarin health effects. The Committee reported that the data were an important step in “determining whether a biologically plausible mechanism could underlie any long-term effects of low exposure to chemical verge agents, but more work Start Printed Page 42413needs to be conducted to elucidate potential mechanisms and clarify how the cellular effects are related to any clinical effects that might be seen.”
The Committee reported that, in the absence of carefully designed human studies expressly of sarin's or cyclosarin's long-term health effects at doses that do not produce acute signs and symptoms, the Committee concludes that the data remain inadequate or insufficient to determine whether persistent long-term effects are associated with low-level sarin exposure.
At a briefing to VA in August 2004, when questioned about whether NAS emphasis on human studies might overlook health concerns revealed only in laboratory animal studies, the head of the Committee stated that the Committee did thoroughly review available animal studies and taken together, they failed to show consistent biological effects that could be plausibly tied to potential clinical effects in humans. He added that future animal studies might change that result.
IV. The Committee's Conclusions
In its report, the Committee weighed the strengths and limitations of all the epidemiological evidence reviewed for the August 2004 Update and in Gulf War and Health Volume 1, and reached its conclusions by interpreting the new evidence in the context of the entire body of literature. The Committee classified the evidence of an association between exposure to sarin and cyclosarin and a specific health outcome with reference to five categories: sufficient evidence of a causal relationship, sufficient evidence of an association, limited/suggestive evidence of an association, inadequate/insufficient evidence of an association, and limited/suggestive evidence of no association.
- Sufficient Evidence of a Causal Relationship: This category means the evidence is sufficient to conclude that there is a causal association between exposure to a specific agent and a specific health outcome in humans. The evidence is supported by experimental data and fulfills the guidelines for sufficient evidence of an association. The evidence must be biologically plausible and satisfy several of the guidelines used to assess causality, such as: strength of association, dose-response relationship, consistency of association, and a temporal relationship.
The Committee found there is sufficient evidence of a causal relationship between acute high-dose exposure to sarin and acute cholinergic syndrome that is evident seconds to hours subsequent to sarin exposure and resolves in days to months. The Committee noted that acute cholinergic syndrome has been recognized for decades, and that the syndrome, as well as cholinergic signs and symptoms, is evident seconds to hours after exposure and usually resolves in days to months.
- Sufficient Evidence of an Association: This category means the evidence is sufficient to conclude that there is a positive association. That is, a consistent positive association has been observed between exposure to a specific agent and a specific health outcome in human studies in which chance and bias, including confounding, could be ruled out with reasonable confidence. For example, several high-quality studies report consistent positive associations, and the studies are sufficiently free of bias, including adequate control for confounding.
The Committee made no conclusions in this category.
- Limited/Suggestive Evidence of an Association: This category means the evidence is suggestive of an association between exposure to a specific agent and a specific health outcome, but the body of evidence is limited by the inability to rule out chance and bias, including confounding, with confidence. For example, at least one high-quality study reports a positive association that is sufficiently free of bias, including adequate control for confounding. Other corroborating studies provide support for the association, but they are not sufficiently free of bias, including confounding. Alternatively, several studies of lower quality show consistent positive associations, and the results are probably not due to bias, including confounding.
The Committee found there is limited/suggestive evidence of an association between exposure to sarin at doses sufficient to cause acute cholinergic signs and symptoms and a variety of subsequent long-term neurological effects. The Committee noted that many health effects are reported in the literature to persist after such high-dose sarin exposure: fatigue, headache, visual disturbances (asthenopia, blurred vision, and narrowing of the visual field), asthenia, shoulder stiffness, and symptoms of posttraumatic stress disorder. The Committee further stated that such sarin exposure has also been followed by abnormal test results, of unknown clinical significance, on the digit symbol test of psychomotor performance, EEG records of sleep, event-related potential, visual evoked potential, and computerized posturography.
The Committee based its conclusion on the persistent effects seen in retrospective studies of three exposed populations in which acute cholinergic signs and symptoms were documented as acute effects of exposure. However, the Committee explained that while a review of the literature published since the Committee's initial report confirmed the effects seen in those populations, the data, taken together, were not adequate to increase confidence in the evidence to that of sufficient evidence of an association.
- Inadequate/Insufficient Evidence: This category means the evidence is of insufficient quantity, quality, or consistency to permit a conclusion regarding the existence of an association between exposure to a specific agent and a specific health outcome in humans.
The Committee found there is inadequate/insufficient evidence to determine whether an association does or does not exist between exposure to sarin at low doses insufficient to cause acute cholinergic signs and symptoms and subsequent long-term adverse neurological health effects. In the absence of carefully designed human studies expressly of sarin or cyclosarin's long-term health effects at doses that do not produce acute signs and symptoms, the Committee concluded that the data remain inadequate or insufficient to determine whether such long-term effects are associated with low-level sarin exposure.
The Committee also found there is inadequate/insufficient evidence to determine whether an association does or does not exist between exposure to sarin and subsequent long-term cardiovascular effects. Studies of persistent cardiovascular effects after sarin exposure have been inconsistent. Therefore, the Committee concluded that the data are inadequate or insufficient to determine whether an association exists.
- Limited/Suggestive Evidence of No Association: This category means the evidence is consistent in not showing a positive association between exposure to a specific agent and a specific health outcome after exposure of any magnitude. A conclusion of no association is inevitably limited to the conditions, magnitudes of exposure, and length of observation in the available studies. The possibility of a very small increase in risk after exposure studied cannot be excluded.
The Committee made no conclusions in this category.Start Printed Page 42414
V. Response to the NAS Report
After careful review of the findings of the August 2004 NAS report, the Secretary has determined that the conclusions contained in the report do not provide adequate basis to support a presumption of service connection for any health condition resulting from sarin exposure. Specifically, the Secretary has determined that the 2004 NAS Committee conclusions concerning both acute high-dose exposure to sarin and low-level exposure to sarin are consistent with the findings in the 2000 NAS report, and therefore do not warrant any change in current VA policy.
Following the 2000 NAS report, VA determined that a presumption based on acute high-dose exposure was not warranted for a number of reasons. First, VA and Department of Defense have determined, with a high degree of confidence, that no service members were exposed to levels of sarin sufficient to induce acute cholinergic syndrome. Further, if such exposures had occurred, the symptoms would have been present within seconds to hours following exposure and would be compensable by VA on a direct service-connection basis. Additionally, any long-term neurological effects would be compensable under VA presumptions for undiagnosed illness. See 38 CFR 3.317. Finally, because it is very unlikely that a presumption would benefit anyone, such a presumption would likely be confusing and have a negative impact on the claims adjudication process.
Nothing in the 2004 NAS report changes the bases for VA's prior determination. The 2004 report notes that current available information is “consistent with the absence of reports of acute cholinergic symptoms by medical personnel or veterans” and that the level of exposure experienced by service members during the Gulf War “would have been insufficient to produce the cholinergic syndrome.”
Similarly, the Secretary has determined that the conclusions contained in the 2004 NAS report regarding long-term health effects from exposure to low levels of sarin are essentially identical and lend further support to the conclusions contained in the 2000 report. Based upon the findings contained in the 2000 NAS report, the Secretary determined that there was not an adequate basis to support establishing a presumption of service connection for any health problem resulting from sarin exposure. NAS's findings in the 2004 Update provide further support for existing VA policy on these issues.
In conclusion, the Secretary has determined that the findings in the 2004 NAS report did not provide any new basis to establish a presumption of service connection for any diseases, illnesses, or health effects resulting from exposure to sarin during service in the Persian Gulf during the Persian Gulf War. Therefore, the Secretary has determined that there is no scientific basis to revise earlier policy determinations published in the Federal Register at 66 FR 35702 on July 6, 2001, on health effects from exposure to sarin based upon the NAS's 2000 Report.Start Signature
Approved: July 11, 2008.
Gordon H. Mansfield,
Deputy Secretary of Veterans Affairs.
[FR Doc. E8-16525 Filed 7-18-08; 8:45 am]
BILLING CODE 8320-01-P