[ RadSafe ] Special Session on Radiation in Flight
jjshonka at shonka.com
jjshonka at shonka.com
Mon Feb 2 20:35:40 CST 2015
There is a profound healthy worker effect in air crew. Sick ones aren’t hired ( in fact, the workers hired are typically healthier than average) and those that get sick are fired. Not sure how one would account for hormesis in that uncontrolled experimental environment given a correction is made for healthy workers. Also, exposure characteristics vary greatly. For example, commuter type aircraft rarely fly above 8 kilometers, and their aircrew do not have significant exposures to cosmic radiation.
John Boice in 2000 summarized epi studies of aircrew in the HPJ (papers were from the 1998 NCRP annual meeting devoted to this topic) For example, one of those studies summarized by John was of 2740 Canadian pilots in 1996 by Band et al. (paper available at: http://aje.oxfordjournals.org/content/143/2/137.full.pdf)
Table 4 of Band et al. shows an incidence of 6 AML cancers observed with only 1.27 expected. Prostate cancer was also found in excess. The conclusions state "the incidence rate for AML, the leukemia type most strongly associated with radiation exposure (two references are cited), significantly exceeded the expected number. AML was also the main type of non-CLL found among British Airways and Canadian Pacific Airlines pilots.”
Another paper that included the lead FAA scientist (Friedberg) as one author was published in Advances in Space Research in 2003.
OVERVIEW OF ATMOSPHERIC IONIZING RADIATION (AIR) RESEARCH: SST-PRESENT J.W. Wilson, P. Goldhagen, V. Rafnsson, J. M. Clem, G. De Angelis, W. Friedberg.
This paper is also available on the web. It summarized 13 epi studies from the early 1990s to early 2000s all of which showed an excess, with 15 types of cancers seen among them.
As was pointed out, there are also studies that have shown no effect. Radiation is a weak carcinogen, and exposures vary.
The USDOE is actively working on an effort to resolve LNT with past worker exposures. There is hope that by combining data from many workers, statistical strength can be improved at exposures less than seen in Japan with significantly more cases. If successful, over decades, it will sort of “fill in the blanks” from higher exposures to ones that are greater than background, permitting a more definitive answer on the LNT theory. Given that aircrew are averaging 3 mSv per year with some having significantly higher exposures, and given that the population has unique characteristics compared to DOE workers (only external exposure, significant neutron component, unique population, etc.) I think it would be useful to add aircrew as another group to expand that study.
Sent from Windows Mail
From: Robert Cihak
Sent: Monday, February 2, 2015 6:17 PM
To: The International Radiation Protection (Health Physics) Mailing List
Is any radiation hormesis observed in airline employees?
Or is anybody following these flying airline employees to assess any adaptive response (hormesis) in these low-level radiation workers? The Naval Shipyard Workers study was not designed to look for a hormetic response; John Cameron at U. Wisconsin extracted and published striking data anyway. Cf. http://inderscience.metapress.com/content/8r5vkpfqvuh5lqf7/ . I would think airline employees would be a natural hormesis experiment. I won't be attending the Special Session on Radiation in Flight but would like to hear about it from attendees, especially if any such research is going on or planned.
Robert J. Cihak, M.D.
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