[ RadSafe ] Any comment on the latest paper in The BMJ

[KARAM, PHILIP]

One thing that jumps out at me is the same thing that concerned me about Cardis' earlier paper purporting to show LNT response from a large cohort of rad workers. There is no binning of doses so it's not possible to tell if there's a dose/effect relationship. They report an average individual exposure of 22.5 mSv among the UK workers, but I'm pretty sure that some of these workers received higher lifetime exposure just as some received less. The bottom line is that their data doesn't seem to prove anything.

For example - they report on 147,866 radiation workers in the UK with an average individual dose of 22.5 mGy and 7558 "all cancer" deaths over a 55-year period. But how many of those cancers came from people with doses of, say, 0-10 mSv compared to those with doses of 90-100 mSv? Looking at this, we can't tell if all of the cancers were seen in the lowest-dose cohorts, the highest-dose cohorts, spread evenly among all cohorts, or something different. Thus, I'm not sure it's appropriate for them to claim that these data support any specific interpretation.

I emailed Cardis with a similar question after her earlier paper - asking if she could share her more granular data as to the numbers of cancers for each range of doses - unfortunately I never heard back from her. But I would suggest that, without this information, neither of these papers can be used to prove anything.

Andy


-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of parthasarathy k s
Sent: Sunday, November 01, 2015 8:09 PM
To: The International Radiation Protection (Health Physics) Mailing List
Subject: [ RadSafe ] Any comment on the latest paper in The BMJ

Our newsgroup has apparently ignored tha following paper published in The BMJ
http://www.bmj.com/content/351/bmj.h5359

Under what this study adds are the following comments:
"The study provides a direct estimate of the association between protracted low dose exposure to ionising radiation and solid cancer mortality. Although high dose rate exposures are thought to be more dangerous than low dose rate exposures, the risk per unit of radiation dose for cancer among radiation workers was similar to estimates derived from studies of Japanese atomic bomb survivors. Quantifying the cancer risks associated with protracted radiation exposures can help strengthen the foundation for radiation protection standards". 

Warm regardsParthasarathy
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