[ RadSafe ] Question on occupational radiation exposure risk - 15 country study

[goldinem at songs.sce.com]

Somehow I've been roped into helping some high school students on a
radiation biology project.  I suggested that they look into some major
epidemiological questions - one them being the risk from occupational
exposure.  I have the BMJ Cardis paper on the 15 countries and had a
quick question.  The cumulative exposure for the workers under
consideration averaged about 20 mSv.  But for the sake of argument, most
of the workers are about 40 years old so they'd have an additional 100
or more mSv from natural background alone.  I am far from an
epidemiologist but I assume that the basis for the risk coefficient
development was the determination of risks as a function of dose for the
dose distributions.  But wouldn't the variability in natural background
be a huge confounder?  I didn't see anywhere in the paper where natural
radiation exposure was even addressed.

Anyone have any clue whether that was considered or am I just missing
it?   Thanks, Eric

Eric M. Goldin, CHP
<goldinem at songs.sce.com>