Dumb questions and comments on ecological/case studies

[Ted de Castro <tdc@XRAYTED.COM>]

Since it seems that we RADSAFERS cannot be explained to in terms simple

enough for posting and since is really important for us all - I'd like

to pose a few comments/questions that at least for me have a

considerable bearing on my understanding of this discussion.  I would

very much appreciate it if the experts could answer the questions and/or

respond to the comments.



First - it seems that in nature NOTHING is simple - the very idea that a

response could be strictly linear seems completely unnatural.



It is also truly impressive that a small effect can be discerned let

alone quantitized or signed in the presence of an overwhelmingly large

confounder.



Ok - lets say we start with the simplest case - one and only one effect

which is strictly and completely linear to the one and one one effect. 

This case is just as simply mathematically so virtually anyone could

understand this one.  Here data from any study should be as good as data

from any other whether aggregate or individual.  OK?



Next step - two or more causes for one effect - all completely linear

AND independent.  The arithmetic here would be JUST as simple and either

study would be as good - since linear is linear and average is average. 

Straight forward.



BUT - now here is the first rub - I submit that the relation CANNOT EVER

be completely linear simply because the effect is not!  Its binary -

cancer or no cancer!  For the first case I don't believe the math

changes BUT for the second it certainly does because the agents can no

longer be independent - it is quite simply the case that once a cancer

is initiated (the hit is scored) it is out of the game.  AT LEAST the

susceptible population is now changed and further exposures to this

individual no longer count.  I also suspect - and this is not as well

thought out - that maybe the exposure prior to the hit being scored of

the agent that didn't cause the hit doesn't count either - and of course

there is no way of knowing which agent scored the hit.



So now we know the agents cannot be independent because of the nature of

the effect - if the response to the agent is also non linear it now

matters even more WHO was exposed and WHO got the cancer and HOW much

that person was exposed to. I have a hard time believing that this can

be discerned accurately by interviews and an even harder time

understanding how this can be factored out of aggregate data - which is

of course faceless.



Now this brings us to an obvious question - When do you stop counting

dose?  Any dose from anything AFTER the cancer is initiated simple

doesn't count so what latency factors are used for the time before

diagnosis/death and is this accounted for in either of the studies and

how can it be discerned from aggregate data.  NOTE I'm not asking how it

was corrected for or factored out - but how it was even discerned (if

this is even a valid/relevant question).



LASTLY - bet you never thought I'd get there - how about exposure after

diagnosis?  Surely a lifelong addicted smoker is not going to quit or

slow down after diagnosis and was probably on the high end of the

consumption curve to begin with.  This must SURELY be distorting in any

kind of study and in the aggregate data must account for the lions share

of the tobacco sales tax!  Probably something like the 80/20 rule.



So - LNT is STILL only a hypothesis and regardless how much money is

made from how many awards based on LNT it is still only a hypothesis and

it is the job of scientists to debate and discuss and test hypotheses. 

It is FAR from proven - it is merely incredible convenient - can be

calculated on a 4 function calculator.



So - if these questions/comments aren't too inane - they are state/posed

sincerely and seriously and I'd appreciate a serious answer.  A simple

one if possible would be all the better.



Thank-you





ps - notice I didn't refer to lawyers at all.

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