"Low Level
Radiation Health Effects: Compiling  the Data"

Revision 1
March 19, 1998
by Radiation, Science, and Health, Inc.,
Edited by J. Muckerheide

1.2.2
Ocupational

1.2.2.1
Weapons Plant Workers

References

"The IARC report states explicitly in the Statistical Methods section that they applied (they presumed) the linear model across 11 dose categories, and that ‘As there was no reason to suspect that exposure to radiation would be associated with a decrease in risk..., one-sided tests are presented throughout.’ This states that they effectively discount and ignore all negative data.

"For the table, the eleven dose categories were collapsed to seven, resulting in greater-than-expected leukemias in three of the seven dose groups (the * groups in Table 2). Since only positive data are allowed to be considered, only the data from the three greater-than-expected dose groups are used, even though these dose groups are not even contiguous. Since the selected data are not significant, the IARC reports that it performs a Monte Carlo calculation on 5,000 trials (effectively multiplying the data by roughly a factor of 100) to ‘find’ that the results show a ‘significant’ linear dose-response ‘trend ‘.

"This ‘result’ was then the subject of a world-wide media campaign, reasonably reported even in Nuclear News, that the ‘linear model’ is confirmed. This report was widely distributed and accepted long before the data and analysis were published and available for review.

"IARC also reports that the 44 multiple myeloma deaths are similarly found ‘significant’, noting that this is ‘attributable primarily to the associations reported previously ... in the Hanford and Sellafield cohorts.’ This note indicates that they are aware, without so stating, that this ‘association’ is not found in other cohorts and is generally considered to be erroneous in the referenced studies, consistent with the weakness in the dosimetry and the confounding effects. (The study reports that cancer relative risk is 0.99 and leukemia is 1.22 at 10 cSv.)"

"In an April 1996 report to the NCRP on this study, Dr. Ethyl Gilbert did not report that the study found support for the "linear model" in the data. However, the NCRP summary of the meeting explicitly attributed to Dr. Gilbert the conclusion that the IARC study had found confirming evidence of the "linear model."

Note: for this table, 11 dose categories were collapsed to 7 (without explanation)