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CHAPTER 6
What Will Happen to the A-Bomb Database? A Pending Proposal
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Right now, the A-Bomb Study has reached a crossroad where
decisions must be made by RERF and RERF's sponsors on how to
preserve the study's legitimacy as a prospective epidemiological
inquiry -- with all the normal continuity and safeguards expected
of such a study -- and how not to sacrifice it (needlessly) in the
quest for a better dosimetry.
We say "needlessly" because this book will show how improved
dosimetries can be ADDED to the A-Bomb Study without destroying
its continuity and its legitimacy as a first-class prospective
inquiry.
Key Role of the 1950-1982 Follow-Up :
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The first step in our proposal is to identify the study's
valid prospective structure. Chapter 5 demonstrates that there has
been substantial continuity of doses, cohorts, and structure of
the study during the 1950-1970, 1950-1974, 1950-1978, and
1950-1982 follow-ups (Table 5-A).
Although the "change no input" rule and others were bent in
the handling of this database during those follow-ups, the rules
were not broken badly enough to nullify the study's credibility as
a uniquely valuable prospective inquiry into the effect of
ionizing radiation upon human cancer-rates. We reach this
conclusion largely because the rule-bending occurred while
relatively little of the cancer-outcome was known. Even by late
1982, about two-thirds of the study's population was still alive,
and more of the cancer-story lay in the study's future than in its
past.
It is clear from Chapter 5 that the 1950-1982 follow-up is
currently the LAST complete follow-up where there is substantial
continuity of doses, cohorts, and structure. Therefore, the
1950-1982 follow-up represents the proper base for subsequent
follow-ups, if the A-Bomb Study is going to maintain the
continuity which is required of all prospective studies.
A Simple Proposal :
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Our proposal is that the eight 1950-1982 dose-cohorts of
A-bomb survivors (Table 5-A) now be "frozen" and kept intact as
the base for all the remaining follow-ups of the Life Span Study.
Membership in a cohort would be virtually immutable from 1982
onward, in the normal manner of a prospective study. Thus, there
would be no change in any cohort's mean age at the time of
bombing, no change in any cohort's initial male-female ratio, and
no movement of any cancer-deaths from one cohort to another. Of
course, there would also be no further alteration of any cohort's
mean T65DR dose.
These eight stable dose-cohorts would be "set in concrete" and
observed for health effects for their full remaining lifespans as
"constant cohorts." The five existing age-bands would also remain
undisturbed. If the study is continued in this manner, no one
would be entitled to "raise an eyebrow" skeptically about the
objectivity of the T65DR database, or to question its scientific
worth due to irregular, unacceptable, or sub-standard handling.
Then, as SUPPLEMENTAL information appended to the study, the
new DS86 dose-estimates for these same cohorts of persons could be
(and should be) provided.
This "dual dosimetry" would permit everyone to benefit from
the insights about dosimetry which occurred AFTER the eight
cohorts were established. Indeed, the proposal could easily handle
the continual "enhancing" of the current DS86 dosimetry which is
planned for the future. With this approach, even a possible 24th
iteration of DS86 would in no way disrupt the permanent
architecture of the T65DR database.
In short, we propose to append the DS86 dosimetry to the
EXISTING structure of the A-Bomb Study, without sacrificing the
study's T65DR anchor into the world of legitimate prospective
research.
Demonstration of the Proposal :
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The simplicity of the proposal is demonstrated in Chapters 13,
14, 15, and 16 of this book, where we do analyses in BOTH
dosimetries for the SAME sets of persons. While only the T65DR
results have the standing of a prospective study, the supplemental
and parallel DS86 results provide a basis on which analysts can
properly propose any hypothesis which they regard as justified by
the results in DS86.
We repeat a reminder published elsewhere: Under the basic
rules of research, the DS86 database can never have legitimacy as
an integral part -- much less the only part -- of a prospective
inquiry (Go89b).
Everything to Gain, Nothing to Lose :
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The "constant-cohort, dual-dosimetry" proposal offers
everything to gain, and nothing to lose. By keeping the T65DR
dosimetry and database intact, one gains both the scientific
credibility which belongs to a well-conducted prospective study,
and yet one is able to find out what the results would be with a
different dosimetry.
By contrast, one loses everything if the T65DR database is
sent to oblivion and if it is replaced by a new dosimetry and a
new structure. In effect, the on-going study would be terminated
and a new one would begin -- not with a clean slate, but with all
the cumulative results through 1982 at hand.
In addition, RERF and NAS have stated the intention to
continue altering the study's input indefinitely, even after
introducing the DS86 database. Their enthusiasm for an
ever-improving dosimetry may have caused them to give insufficient
weight to the unwanted consequences of such practices upon the
future scientific credibility of the whole effort.
A Pending Decision :
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After all the suffering in Hiroshima and Nagasaki, and after
all the decades of hard work to extract important biomedical
information for humanity from that experience, the A-Bomb Study
has now reached the crossroad which we have described in this
chapter and the previous one.
No one wants to throw away the chance to continue this
uniquely valuable A-Bomb Study as a first-class prospective
inquiry. Surely everyone must want to help protect it from being
subjected, needlessly and forever, to the criticism that its
handling was epidemiologically unacceptable. And skepticism about
standards in health research is becoming very common (see Chapter
24, Part 1, "A Distasteful Subject").
Following our correspondence with RERF on this issue in 1988
(see Chapter 5), we opted to leave the matter at rest until we
were able to DEMONSTRATE our proposal to RERF, NAS, and interested
epidemiologists. This book provides the demonstration. Neither we
nor anyone else can ever use this "constant-cohort,
dual-dosimetry" approach beyond the 1982 follow-up, unless RERF
and RERF's sponsors make a favorable decision about our proposal.
The decision may affect more than the A-Bomb Study. Practices
affecting a world-famous database are likely also to have
international repercussions for the standards of biomedical
research in general -- far beyond the single field of ionizing
radiation.
For both reasons, we regard the issue as one of the most
important topics of this book.
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