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TESTIMONY OF
DRUE H. BARRETT, PH.D.
DIVISION OF ENVIRONMENTAL HAZARDS AND HEALTH EFFECTS
NATIONAL CENTER FOR ENVIRONMENTAL HEALTH
CENTERS FOR DISEASE CONTROL AND PREVENTION
U.S. PUBLIC HEALTH SERVICE
BEFORE THE
SUBCOMMITTEE ON LABOR, HEALTH AND HUMAN SERVICES, AND
EDUCATION
COMMITTEE ON APPROPRIATIONS
U.S. SENATE
OCTOBER 5, 2000
Mr. Chairman, thank you for the opportunity to update the
Subcommittee on the Centers for Disease Control and Prevention=s
(CDC) research programs pertaining to Gulf War veterans=
illnesses. I am Dr. Drue Barrett, Chief of the Veterans=
Health Activity Working Group in the Division of Environmental
Hazards and Health Effects of the National Center for Environmental
Health (NCEH). I serve as CDC=s
liaison to the Department of Health and Human Services (HHS)
on Gulf War issues. I a member of the Research Working Group
that serves the Persian Gulf Veterans Coordinating Board and
the Military and Veterans Health Coordinating Board. NCEH
has been designated as the lead Center at CDC for addressing
Gulf War veterans=
health concerns, however other Centers within CDC have also
been involved in this effort, most notably, the National Center
for Infectious Diseases.
The purpose of my testimony is to provide the Subcommittee
with background information on what is currently known about
illnesses among Gulf War veterans and the possible relationship
between these illnesses and environmental hazards encountered
during the Gulf War. My testimony will include a discussion
of the recent Institute of Medicine (IOM) report on depleted
uranium, sarin, pyridostigmine bromide, and vaccines, a review
of CDC=s Gulf War
research activities, and an assessment of the Federal research
effort to address the health concerns of Gulf War veterans.
Background
Shortly after the end of the Gulf War, reports began to emerge
that veterans were experiencing a variety of somatic symptoms
generally not accompanied by physical signs or laboratory
abnormalities. The most commonly reported symptoms include
complaints of chronic fatigue, headache, muscle and joint
aches and pains, and cognitive disturbances.
In 1994, the findings of a National Institutes of Health
Technology Assessment Workshop established the priority of
conducting controlled epidemiologic research to determine
the prevalence of symptoms among Gulf War veterans and a number
of such studies have been completed. This research effort
has included population-based studies, including cross-sectional
and longitudinal cohort studies; cluster and cross-sectional
studies of specific military units, commands, or branches
of service; and studies of U.S. and other coalition forces.
Importantly, control subjects have been assessed in order
to compare prevalence rates across groups. These control groups
have included military personnel activated during the time
of the Gulf War who remained stateside, troops deployed to
other regions during the Gulf War, and military participants
in other conflicts. Assessment approaches have included mail
and telephone surveys, in person questionnaires and interviews,
and physical examinations. The number of respondents participating
in these studies have ranged from a few hundred to over 20,000.
Response rates have ranged from poor (31%) to very good (76%).
The findings of these studies have been remarkably consistent,
regardless of the study methodology employed. Active duty
and reserve personnel deployed to the Gulf War report nearly
all assessed symptoms at a higher rate than comparison groups.
Gulf War veterans are also more likely to rate their overall
health status since the Gulf War as poorer than their non-deployed
peers. The most useful or generalizable studies of symptom
prevalence have been population-based, have used a comparable
control group of military era personnel not deployed to the
Gulf, and have used at least some standardized or validated
instruments to allow comparisons to other populations or studies.
A number of environmental exposures have been mentioned
in relation to Gulf War veterans=
health concerns. These have included environmental and occupational
pollutants (e.g., sand, petroleum products, pesticides, Chemical
Agent Resistant Coating paint, smoke from oil-well fires),
medical prophylaxes (e.g., anthrax and botulinum toxin vaccines
and pyridostigmine bromide), depleted uranium munitions, and
biologic and chemical warfare agents. Several studies have
explored the relationship between exposures during the Gulf
War and subsequent health outcomes. However, as noted by the
IOM in their recent report, this research has been hampered
by a lack of objective exposure data. Since most studies have
examined the association between retrospective recall of exposures
and self-reported health outcomes, it has been difficult to
eliminate the impact of potential recall bias. To date, no
specific exposure has been identified as responsible for the
various health complaints of Gulf War veterans.
IOM Report on Gulf War Exposures and Health
In an effort to further examine the health effects associated
with exposures encountered during the Gulf War, the IOM reviewed
the scientific and medical literature on depleted uranium,
sarin, pyridostigmine bromide, and vaccination against botulinum
toxin and anthrax. Because of the lack of data on actual exposures
among Gulf War veterans, the committee was not able to assess
the likelihood that Gulf War veterans=
health problems are associated with or caused by these agents.
Instead most of the conclusions in the report are based on
occupational and clinical exposures. The committee did find
sufficient evidence for some transient acute health effects
associated with high doses of pyridostigmine bromide (such
as those used in treatment of myasthenia gravis) and with
anthrax and botulinum toxoid vaccinations. They found sufficient
evidence of a causal relationship between exposure to sarin
and a dose-dependent acute cholinergic syndrome that develops
in seconds to hours subsequent to sarin exposure and resolves
in days to months and limited/suggestive evidence of an association
between exposure to sarin at doses sufficient to cause acute
cholinergic effects and subsequent long-term health effects.
Other than the findings for sarin, the committee concluded
that there was inadequate or insufficient evidence to make
a determination that the exposures would result in long-term
adverse health effects. The IOM based their conclusions on
an exhaustive review of 1,000 peer reviewed journal articles.
Although the IOM findings cannot provide conclusive answers
about the health impact of these exposures on Gulf War veterans,
this report may provide some reassurance that among other
populations there does not seem to be strong evidence that
in the absence of acute effects these exposures are associated
with long term health effects.
CDC-funded Gulf War Studies:
In order to further explore what is known about Gulf War
veterans= health
concerns, I would like to review CDC=s
research activities in this area. CDC=s
initial efforts were to examine the health impact of the oil
well fires. Researchers from the NCEH and several other Federal
agencies conducted cross-sectional surveys of workers in Kuwait
City in May 1991 and of firefighters in the oil fields in
October 1991. Blood samples were tested for 31 volatile organic
compounds (VOCs) and compared to a referent group of persons
living in the United States collected as part of the third
National Health and Nutrition Examination Survey (NHANES III).
The median concentration of VOCs among the firefighters was
quite elevated. However, among the non-firefighting personnel,
VOC concentrations were equal to or lower than the levels
found among the reference group.
NCEH also collaborated with the Department of Defense (DoD)
in a study of 30 members of an Army Unit located in Germany.
Blood from these military personnel was tested for VOCs at
three points in time, prior, during and after their deployment
to Kuwait. Only one compound, tetrachloroethylene, was found
to be elevated. This is a compound found in degreasing agents
used to clean equipment.
In 1994, CDC collaborated with the Mississippi Department
of Health and the Department of Veterans Affairs (VA) on an
assessment of reports of adverse birth outcomes among members
of two Mississippi National Guard Units that served in the
Gulf War. This investigation found no increase above expected
rates in the total number of birth defects, or the frequency
of premature birth and low birth weight. The frequency of
other health problems such as respiratory infections, gastroenteritis,
and skin diseases among children born to these veterans also
did not appear to be elevated. Due to the small sample size,
this investigation was unable to assess individual categories
of birth defects.
In 1994, CDC initiated an epidemiologic study of Gulf War
veterans from Iowa. The Iowa study, conducted in collaboration
with the Iowa Department of Public Health and the University
of Iowa, was one of the first population-based epidemiologic
studies to document that Gulf War veterans are reporting more
medical and psychiatric conditions than their non-deployed
military peers. In fact, this study was recently described
by IOM as Aperhaps
the strongest study on Gulf War veterans=
experience of symptoms related to deployment in the Gulf.@
The 3,695 subjects who completed this study were selected
from a larger population of almost 29,000 military personnel
who listed Iowa as their home of record. Furthermore, the
subjects in this study were specifically selected to represent
individuals from all four branches of the military, and include
both regular military personnel and National Guard and reservists.
Seventy-six percent of the eligible study subjects completed
the detailed telephone interviews. This study is also one
of the first controlled epidemiological studies to evaluate
the health consequences of the Gulf War. The study included
a carefully selected comparison group of military personnel
who were not deployed to the Persian Gulf but who served during
the time of the Gulf War. The Iowa study found that the Gulf
War military personnel were more likely than those who did
not serve in the Gulf War to report symptoms suggestive of
cognitive dysfunction, depression, chronic fatigue, post-traumatic
stress disorder, and respiratory illness (asthma and bronchitis).
The conditions identified in this study appear to have had
a measurable impact on the functional activity and daily lives
of these Gulf War veterans. Among Gulf War veterans, minimal
differences were observed between the National Guard or reserve
troops and the regular military personnel. The results of
the Iowa study were published in the Journal of the American
Medical Association in 1997.
More recently the Iowa data has been examined to determine
whether the health complaints of Gulf War veterans represent
a novel illness unique to service in the Persian Gulf. We
assumed that if there was a Gulf War syndrome, the symptom
pattern would vary between the deployed veterans and the non-deployed
controls. Although Gulf War veterans reported nearly every
symptom more often than those who did not deploy to the Gulf,
we found that Gulf War veterans and non-deployed controls
had the same patterns of symptoms suggesting that the health
complaints of Gulf War veterans are similar to those of the
general military population and are not consistent with the
existence of a unique Gulf War syndrome. This study was published
earlier this year in the American Journal of Medicine.
Also in 1994, CDC initiated a study of Air Force personnel.
This study organized symptoms reported by Air Force Gulf War
veterans into a case definition, characterized clinical features,
and evaluated risk factors. The cross-sectional questionnaire
was sent to 3,723 currently active volunteers from four Air
Force populations. Clinical evaluations were performed on
158 Gulf War veterans from one unit, irrespective of health
status. A case was defined based on reporting one or more
chronic symptoms from at least 2 of 3 categories (fatigue,
mood-cognition and musculoskeletal) and was further characterized
as mild-to-moderate or severe depending on the severity of
the reported symptoms. The prevalence of mild-to-moderate
and severe cases were 39% and 6%, respectively, among 1,155
Gulf War veterans versus 14% and 0.7% among 2,520 non-deployed
veterans. Fifty-nine (37%) clinically evaluated Gulf War veterans
were non-cases, 86 (54%) were mild-to-moderate cases and 13
(8%) were severe cases. The key observation of the study was
that Air Force Gulf War veterans were significantly more likely
to meet criteria for severe and mild-to-moderate illness than
were non-deployed personnel. There was no association between
the chronic multisymptom illness and risk factors specific
to combat in the Gulf War (month of season of deployment,
duration of deployment, duties in the Gulf War, direct participation
in combat, or locality of Gulf War service). The finding that
15% of non-deployed veterans also met illness criteria was
equally important and suggests that the multisymptom illness
observed in this population is not unique to Gulf War service.
The clinical evaluation component of the study found that
neither mild-to-moderate nor severe cases were associated
with clinically significant abnormalities on physical examination
or routine laboratory tests. However, Gulf War veterans classified
as having mild-to-moderate and severe illness had a significant
decrease in functioning and well-being compared with non-cases.
The results from this study were published in CDC=s
Morbidity and Mortality Weekly Report in 1995 and in
the Journal of the American Medical Association in
1998.
Subsequent analyses of data from the Air Force study have
examined the association between physical, chemical, and emotional
deployment stressors reported by Gulf War veterans and the
development of chronic multisymptom illness following the
war. The illness defined in this study was found to be related
to reporting pyridostigmine bromide use, insect repellent
use, injuries that required medical attention, and a belief
that biological or chemical weapons had been used. These findings
were published earlier this year in the Journal of Nervous
and Mental Disorders.
CDC is currently funding a follow-up to the Iowa study focusing
on evaluating self-reported symptoms of asthma. This study
involves a detailed clinical evaluation of a sample of subjects
who completed the initial telephone survey. This evaluation
includes a physical examination; tests of lung functioning;
questions regarding medical, occupational, and exposure history;
assessment of functional status and quality of life; and assessment
of psychiatric history and personality functioning. The examinations
are being conducted at the University of Iowa Hospitals and
Clinics in Iowa City, Iowa. This study is in its final phases
of data collection.
The University of Iowa has also been funded by DoD to conduct
validation studies of additional health outcomes among participants
of the telephone survey. These include validation of depression,
cognitive dysfunction, and fibromyalgia. CDC is providing
technical assistance to DoD and the University of Iowa for
this study.
We are also funding the Boston University School of Public
Health to conduct a study examining the relationship between
cognitive function and symptom patterns among Gulf War veterans.
In one component of this study, functional magnetic resonance
imaging (fMRI) is being used to examine possible differences
in brain activation patterns between Gulf War veterans and
era controls with different levels of symptoms. A second component
of the study is using a new data-driven mathematical technique,
Logical Analysis of Data, to examine how Gulf War veterans=
symptoms cluster together. This may provide useful information
for determining etiology or for developing a case definition.
Finally, this study also includes a component examining the
neuropsychological functioning of a sample
of Danish Gulf War troops. Investigators are currently
in the data collection phase for the fMRI component of this
study and in the data analysis phase for the other two components.
We anticipate that this study will be complete by the end
of this year.
Finally, CDC is funding the University of Medicine and Dentistry
of New Jersey-Robert Wood Johnson Medical School to conduct
a study examining case definition issues. The study will assess
the persistence and stability of Gulf War veterans symptoms
over time, compare the performance of data-driven case definitions
to existing definitions for medically unexplained symptoms,
and examine the role of psychiatric conditions in Gulf War
veterans= unexplained
illnesses. We originally expected that this study would be
completed in late 2000, however the process of protocol development
and clearance took somewhat longer than we anticipated. Thus,
we expect that this study will require an additional year
to complete.
CDC is also collaborating with DoD and VA on a number of
projects including a study of health outcomes among Saudi
Arabia National Guard members and a study of Amyotrophic Lateral
Sclerosis (ALS) among Gulf War veterans. This collaboration
has included providing input on study protocols, reviewing
human subjects issues, and assisting in laboratory assessments.
HHS Research Planning Efforts:
CDC, in collaboration with other HHS agencies, recently sponsored
a conference to develop future Gulf War research recommendations.
On February 28 through March 2, 1999, CDC brought together
scientists, clinicians, veterans, veterans=
service organizations, Congressional staff, and other interested
parties to discuss and make recommendations regarding the
direction of future research on undiagnosed illnesses among
Gulf War veterans and their links with multiple chemical and
environmental exposures.
Concurrent workgroups were convened in order to develop research
recommendations in four areas: pathophysiology, etiology,
and mechanisms of action; assessment and diagnosis of illnesses;
treatment; and prevention of illnesses in future deployments.
This conference highlighted the importance of including veterans
in the process of planning and implementing research. Veterans
and scientists alike expressed that they found the process
useful and that future similar efforts should be encouraged.
A report was released earlier this year that summarized the
outcome of each of the four workgroup sessions. The recommendations
developed at this conference have been shared with the interagency
Research Working Group and need to be considered in light
of the existing research portfolio in order to avoid unnecessary
duplication of efforts. We are currently developing a call
for research proposals that will build on the recommendations
developed during the conference. We would specifically like
to address the issue of health risk communication and the
development of more effective methods for delivering deployment-related
health information.
Assessment of Federal Research Effort:
The Federal research portfolio on Gulf War veterans=
illnesses has been managed by the Research Working Group of
the Persian Gulf Veterans Coordinating Board and in the near
future will be managed by the Military and Veterans=
Health Coordinating Board. Various agencies within HHS have
participated in the interagency effort to coordinate research,
however the majority of this research has been funded by DoD
and VA. To date there have been 192 federally-funded research
projects on Gulf War veterans=
illnesses. These projects represent a broad spectrum of research
efforts, ranging from small pilot studies to large-scale epidemiology
studies addressing mechanistic, clinical, and epidemiological
issues. Similar efforts have been initiated in other coalition
countries, most notably in the United Kingdom and Canada.
Many of the projects are ongoing and we eagerly await the
results of these studies. In addition to the Federal research
effort, numerous independent review panels and expert committees,
such as the IOM committees, have evaluated the available data
on Gulf War veterans=
illnesses. Despite these extensive research and review efforts,
many questions remain regarding the health impact of the Gulf
War. However, these remaining questions reflect the complexity
of assessing and predicting the health impact of military
deployments. Despite this complexity, the federal research
effort continues in an effort to uncover the causes of illnesses
among Gulf War veterans so that effective treatment approaches
can be developed and similar illnesses in future deployments
can be prevented.
Mr. Chairman, this concludes my testimony. I would be happy
to answer any questions the Subcommittee may have.
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