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APPENDIX C
INTERPRETABILITY OF FOLLOW-UP QUESTIONNAIRE DATA
The follow-up questionnaire was part of a concerted attempt to
determine the nature, extent, and severity of protracted problems
associated with exposure of volunteers to a variety of chemicals at
the Edgewood test site. Considerable discussion and controversy
attended the design and analysis problems. Of particular concern
were the use of a specially constructed but untested questionnaire,
the relatively small groups of men exposed to some chemicals, the
sensitivity of the questionnaire for detecting the problems most
probably associated with exposure, and the potential for causing
extraordinary concern among the volunteer soldiers. Many special-
ists in questionnaire development were consulted regarding the types
of information that might be elicited and the specific wording of
questions. The resulting questionnaire was a compromise agreed on
by the five panels and the National Research Council Committee on
Use of Human Subjects. Several subjects of concern were not in-
cluded in the final questionnaire, such as probes for specific
symptoms, suicide attempts, diseases, treatments, behaviors, de-
tailed history of later job-related exposure, accidents, and spon-
taneous abortions. An issue of great concern was the relatively
small groups of men exposed to the psychochemicals and their effects
on interpretability. Briefly stated, it was felt at the outset by
the panel reviewing psychochemicals that data obtainable from a sur-
vey might add little to our understanding of the long-term health
effects of chemicals tested.
POPULATION
The population to be followed was not contacted regularly after
discharge from the Army and had not consented to or expected a
follow-up attempt. It was therefore difficult to secure the
cooperation and sample sizes desired to make the total response
statistically useful. It is assumed that 6,395 of 6,720 soldiers
were alive at the time of follow-up. Of those, 4,085 (64% of total
or 82% of those located) responded to the questionnaire. Those who
did not respond might not constitute a random sample of the entire
population. It is possible that many of the nonrespondents failed
to respond because they had nothing important to say. If that were
true, it would strengthen our belief that long-lasting effects were
generally not present. However, it is also possible that the
nonrespondents had other reasons for failing to respond, such as
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very low economic status, incarceration, and long-term hospitali-
zation.
The importance of obtaining complete accounting of all those
followed is shown by considering the numbers of subjects exposed to
each drug. Large samples were exposed to the anticholinesterases,
the anticholinergics, and the irritants and vesicants, but fewer
than 100 were exposed to the psychochemical Sernyl. The loss of
respondents in the smaller groups makes the conclusions for Sernyl
more tentative, because of the statistical properties (i.e., power)
of the comparison tests.
QUESTIONNAIRE DESIGN
Most of the problems associated with the questionnaire were due
to a lack of explicit hypotheses as to potential long-term effects
of the drugs studied. Questions of general interest were included,
but specific hypotheses were not assessed with questions. Further-
more, the survey instrument was a questionnaire, not an interview.
The questions therefore had to be simple, easily understood, and
able to be answered quickly. Such constraints limit the specificity
and detail of the information to be collected.
Even given those characteristics of the survey, some of the
questions that were included could have been reworded or recon-
sidered. For example, the section on employment might have been
longer and more complex than necessary; and the question as to
children born to the subject could have indicated more clearly that
unmarried subjects should report the numbers and sexes of their
children.
OTHER CONSIDERATIONS
The climate in which the questionnaire was used might raise
concern about interpretation of the results. For example, subjects
who wished (for whatever reason) to misrepresent the nature and
severity of their problems could distort the results (and hence
their interpretation), especially if their chemical-test group was
fairly small. In addition, as in any cohort study, there was no
control of the subjects' environments after discharge from the
service, so even legitimate complaints associated with exposure to
toxic substances could have been due to occupational or accidental
exposure to chemical agents, rather than to exposure at Edgewood.
SUMMARY
Some caution must be exercised in viewing the data obtained from
the questionnaire. There were constraints on the information that
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could have been gained on long-term effects of chemical exposure,
even if follow-up had been conducted by personal interview with
questions designed to test specific hypotheses. There were differ-
ences among the subjects exposed, including possible misrepresenta-
tion by subjects, variability in their lives after discharge, and an
inherent difficulty of finding a representative follow-up sample
after 10-30 years. Beyond these constraints, interpretation of the
data that were collected entails additional problems. The data on
general health, family, and work status are interpretable and appear
to show good adjustment to civilian life by most of the men sampled.
No major identifiable effects are observable in these data. However,
the limited information available from the follow-up on these soldiers
does not permit definitive conclusions regarding the nature and extent
of possible long-term problems resulting from chemical exposure at
Edgewood.
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Representative terms from entire chapter:
chemical exposure
