AGENT ORANGE AND BIRTH
DEFECTS
Does exposure to Agent Orange or service
in Vietnam increase the likelihood of a veteran fathering a child
with birth defects?
One of the most emotional aspects of the Agent Orange issue is the concern
that exposure to herbicides in Vietnam may have caused or contributed
to the risks of having babies with birth defects. Literally thousands
of Vietnam veterans have children with abnormalities. Considering the
fact that approximately 2.6 million veterans served in Vietnam and the
fact that 3-6 percent of all children are born with some kind of defect,
scientists expect to see many children with abnormalities among the
offspring of Vietnam veterans. Unfortunately, in many instances scientists
cannot explain what caused these birth defects.
Research has been conducted to determine whether exposure to Agent Orange
or military service in Vietnam may have increased the risk of having
children with birth defects. Based on the research completed to date,
the overall answer seems to be "apparently not." In 1996,
the National Academy of Sciences found that there is "limited/suggestive"
evidence of an association between herbicide exposure and one rare birth
defect, spina bifida. For information about spina bifida, see Agent Orange Brief, D11. The Australian birth defects
study, the Centers for Disease Control (CDC) birth defects study, the
Air Force Health Study (Ranch Hand), and the CDC Vietnam Experience
Study all suggest that Agent Orange is not the most likely cause of
the birth defects. Each of these investigations is briefly summarized
below.
Case-Control Study of Congenital Anomalies and Vietnam Service (Birth
Defects Study) - Report to the Minister for Veterans' Affairs -
January þ1983 - Prepared by J. W. Donovan and others. This Australian
investigation involved examination of the hospital and laboratory records
of infants born with birth defects in three populous areas of Australia
between the years 1966 and 1979.
In all, 34 hospitals and 4 laboratories cooperated fully with the investigating
team. Whenever the birth of an infant with a defect was found, it was
matched to a healthy control infant born in the same hospital, to a
mother of similar age, and as close as possible in time to the birth
of the child with the defect. The fathers of both cases (for this study,
a case is a baby with a birth defect) and controls (for this study,
a control is a baby without a birth defect) were identified in 8,517
instances and those identified were compared with a list of every man
who served in the Australian Army between 1962 and 1972, the period
of Australian involvement in Vietnam. Fathers who served in the Army
during this period were then classified according to whether they had
served in Vietnam.
The important finding of the study is that 127 of the fathers of children
with birth defects were Vietnam veterans and 123 veterans were among
the fathers of healthy children. This indicates that there is no evidence
that Army service in Vietnam increased the risk of fathering a child
with a birth defect.
Vietnam Veterans' Risks for Fathering Babies with Birth Defects
- August 1984 - U.S. Department of Health and Human Services, Public
Health Service, Centers for Disease Control, Center for Environmental
Health. Vietnam veterans' risks for fathering babies with major structural
birth defects were assessed using a case-control study. Information
regarding military service in Vietnam was obtained from interviews with
mothers and fathers of babies in case and control groups and from review
of military records.
Vietnam veterans did not have an increased risk of fathering babies
with defects. Furthermore, Vietnam veterans who had greater estimated
opportunities for Agent Orange exposure were not at greater risk for
fathering babies with all types of defects combined.
Air Force Health Study (Project Ranch Hand II) - An Epidemiologic
Investigation of Health Effects in Air Force Personnel Following Exposure
to Herbicides - Periodic reports on morbidity (health problems).
The February 1984 Baseline Morbidity Study Results indicated that there
were no significant differences between the Ranch Hand (the military
unit that did most of the herbicide spraying in Vietnam) and control
groups with regard to severe or moderate birth defects. Based on parental
reports, however, Ranch Hand offspring showed significantly more minor
birth defects (birth marks, etc.).
In 1992, the Air Force study compared blood dioxin levels with reproductive
outcomes. All of the 791 Ranch Hands and 942 comparison subjects who
have measured levels of dioxin in their blood were included in the study.
It analyzed miscarriages, total adverse outcomes, total conceptions,
birth weights, birth defects, birth defect severity, specific and multiple
birth defects, and infant and neonatal deaths. In addition, the study
looked at sperm counts and the percentage of abnormal sperm of study
participants.
Investigations found no adverse relationship
between dioxin and any of these reproductive outcomes, nor between dioxin
and sperm count or percentage of abnormal sperm.
Health Status of Vietnam Veterans - Reproductive Outcomes and Child
Health - The Centers for Disease Control Vietnam Experience Study
- May 1988. The Vietnam Experience Study was a multidimensional assessment
of the health of Vietnam veterans. From a random sample of enlisted
men who entered the U.S. Army from 1965 through 1971, 7,924 Vietnam
and 7,364 non-Vietnam veterans participated in a telephone interview;
a random subsample of 2,490 Vietnam and 1,972 non-Vietnam veterans also
underwent a comprehensive medical examination. Children of Vietnam veterans
were not more likely to have birth defects recorded on hospital birth
records than were children of non-Vietnam veterans. The rates of total,
major, minor, and suspected defects were similar among children of Vietnam
and non-Vietnam veterans.
What did the National Academy of Sciences conclude about birth defects
in its l993 report, entitled Veterans and Agent Orange - Health Effects
of Herbicides Used in Vietnam?
The 832-page NAS report included the following statements:
There is little evidence of a statistical
association between father's occupational exposure to herbicides or
dioxin and birth defects among offspring. The available epidemiologic
studies have been limited by a number of problems, especially inadequate
statistical power for the evaluation of specific birth defects. Studies
involving environmental exposure have yielded inconsistent results;
furthermore, given the ecologic nature of the studies, the limited
sample sizes (for specific defects), and the failure to verify reported
birth defects, the evidence can be considered inadequate for an association....
The results of available epidemiologic
studies of Vietnam veterans are also inconsistent; some studies suggest
a potential association with defects of the central nervous system
and other systems, although others find no increased risk. As noted
for other end points, the veteran studies were generally limited by
inadequate size, marginal magnitude of the increased risk, and the
failure to exclude bias and chance. Moreover, uncertainty regarding
the assessment of exposure among Vietnam veterans and the limited
evidence from other cohorts do not permit one to draw a conclusion
about an increased risk of birth defects among the offspring of men
exposed to herbicides in Vietnam. Future analyses of the Ranch Hand
data may contribute important evidence regarding an increased risk
of birth defects.
What did the NAS conclude birth defects in its 1996 update?
The 1996 update included the following statements:
There is limited/suggestive evidence
between exposure to the herbicides considered in this report and spina
bifida. There is inadequate or insufficient evidence to determine
whether an association exists between exposure to herbicides and all
other birth defects. The evidence regarding association is drawn from
occupation and other studies in which subjects were exposed to a variety
of herbicides and herbicide components....
Since the strongest associations are
from studies of Vietnam veterans and there are some data suggesting
that the highest risks were for those veterans estimated to have had
exposure to Agent Orange (e.g., Ranch Hands), it therefore follows
that there is limited/suggestive
evidence for an increased risk in Vietnam veterans of spina bifida
in offspring.
What can a Vietnam veteran now assume about the risks of birth defects?
Many Vietnam veterans have produced children with birth defects. Many
Vietnam veterans now in or approaching their 50's have wives entering
or in menopause. Therefore, it is likely that Vietnam veterans will
be having fewer children. Nevertheless, there is no doubt that Vietnam
veterans will continue to produce some children with birth defects.
The critical question is "Are Vietnam veterans more likely than
other individuals men to produce children with birth defects?"
Based on all we know from the scientific research described above and
studies of dioxin-contaminated areas in Times Beach, Missouri, and Seveso,
Italy (where investigators concluded "that the data collected contain
no evidence that in the population of the Seveso area exposed
to dioxin; there was greater risk of producing congenitally malformed
offspring."), Vietnam veterans do not seem to be at increased risk
of fathering children with birth defects (with the possible exception
of spina bifida, for which there is "limited/suggestive" evidence
of an association).
(A relatively small number of women served in Vietnam. It is unlikely
that many of them were exposed to Agent Orange. Research is underway
to learn more about what effects Vietnam service may have had on their
health. At this point, there is no scientific evidence that women have
mothered an unexpectedly high number of children with birth defects.)
What is VA doing to learn more about birth defects among the children
of Vietnam veterans and veterans of other wars?
On May 24, 1996, VA announced a "solicitation for applicant to
establish a research center for epidemiological, clinical, and basic
science studies of environmental hazards and their effects on reproductive
and developmental outcomes." On November 14, 1996, VA announced
that the Louisville VA Medical Center was selected as the site of this
center.
Where can a concerned veteran get additional information about birth
defects?
In October 1985, VA published a monograph entitled "Birth Defects
and Genetic Counseling." This publication was distributed to all
VA medical center libraries in 1985. The March of Dimes Birth Defects
Foundation is a source of information on this subject. The address is
Professional Education, March of Dimes Birth Defects Foundation, 1275
Mamaroneck Avenue, White Plains, New York 10605. Other sources of information
include the Easter Seal Society and the Spina Bifida Association of
America.
DioxinKills!
Agent
Orange Brief
| A1
| A2 | B1 | B2
| B3 | B4 | C1
| C2 | C3 |
| D1
| D2 | D3 | D4
| D5 | D6 | D7
| D8 | D9 | D10
| D11 |
