RE: Lung cancer mortality from radon versus mortality from other cancers

["Rad health" <healthrad@HOTMAIL.COM>]

Michael Ford,



Regarding your email below.  From your tone, you really sound a bit agitated 

about this issue. But, our guess is what really bothers you is not the 

quality of the miner studies, but that the LNT is used to extrapolate risks 

down from them - are we right?  But, really haven't we known for a very long 

time that something in the mines was killing people.  No epidemiologic study 

could ever perfectly record all the exposures, but the researchers from 

various parts of the world likely strive to do the best science they can in 

the time periods the various studies were performed.  What you can not help 

but notice is a pattern among all these studies (performed by different 

researchers in various parts of the world) that show an increasing positive 

trend with radon exposure that was estimated in various ways.  If it was 

merely some other factor like silica, then it would also have to be in all 

the mines and co-correlate with radon.



When we are born, we do not have a built in dosimeter that can document all 

exposures we encounter in our life, nor do we have a way to precisely factor 

in all the genetic factors, effect modifiers for each person.  Scientist 

perform the best studies they can at the time and have to live with the 

strengths and limitations of the study.  And we think you right, if we are 

really interested in the quality of a study we should examine each one 

independently for both internal and external validity.  We agree that some 

of the miners studies were better than others.  In fact some miner studies 

did not even collect data on smoking.  But, in all of this we see an 

overwhelming number of the studies produce a positive dose response 

relationship between lung cancer and radon.  We truly do not believe this is 

some worldwide conspiracy. We are hard pressed to think of a larger 

occupational data set confirming that something causes lung cancer.  The 

question is if this information is going to be used for projections to the 

residential setting how good are the risk estimates? The risk estimates 

actually agree pretty well considering the differences between the studies.  

But, with all the differences between the mine and home environment, can 

this be extrapolated to the residential setting?  Well there was a pooling 

of low dose miner studies that predicted the same risk as was extrapolated 

from the the regular miner studies.  But, what about those differences 

between the mine and the home environment such as breathing rate 

differences, gender, particles size differences, and so on.  BEIR VI made 

the case it is OK to extrapolate down and they referenced an article or two 

by researchers at Columbia University to support their action not to 

consider a threshold.  They even admitted that it may not be linear or there 

may be a threshold, who knows for sure.  But at this time they thought that 

most of the data supported the LNT (like most of the miner data results 

being linear).  But, in BEIR VI we also see a statement that says the most 

DIRECT way to examine the risk posed by residential radon is to perform 

epidemiological studies on people who actually live in homes rather than 

mines.



That brings us to the published and on-going residential radon studies.  In 

the United States, the first case-control study was in NJ.  They found a 

positive association between radon exposure and lung cancer, but their 

highest exposure category had very limited numbers (5 or 6) of subjects.  

But this highest exposure category really influenced their findings.  The 

MOI and MOII studies did not find much of an association when they just used 

gas measurements.  Dr. Alavanja the PI for the MO study says (in a letter 

published in the AJE) that the original studies suffered from severe 

exposure misclassification.  The improved exposure misclassification of 

MO-II detected a fairly strong association. Remember with a case-control 

study, poor exposure assessment generally takes the findings toward finding 

less of an association.  These studies were followed by case-control studies 

in IA, Utah, Idaho, and Conn.  I think we are all familiar with the findings 

of the IA study after two weeks of discussions on this list.  The results 

from the all but the combined NIEHS funded Idaho/Utah/Conn study are pretty 

much published for the U.S.  We have been told Iowa will be publishing their 

glass-based results down the road.



A summary of these studies has been published by Dr. Field elsewhere:

http://www.cheec.uiowa.edu/misc/rd_review.pdf



Next up is the pooling of N. American studies followed by a pooling of the 

European residential radon studies.  Eventually, from what we understand is 

that all these studies will eventually be pooled.  In the meantime, more 

scientist are exploring alternatives to gas based measurements such as the 

glass based measurements.  Dr. Alavanja indicated that the MO and IA studies 

will likely have a separate pooling of glass-based measurements.  Further 

calibration of that detector is apparently on-going. Time marches on and we 

learn as we go.  Each new finding hopefully adds a greater understanding of 

what we do and do not know.



But Michael, we have read the studies.



The Dons (consortium of graduate students and post docs interested in radon 

epidemiology). Classes start next week so we are out of here.  And Oprah, 

please call Dave.







>From: "Michael Ford" <MFORD@PANTEX.COM>

>Dear Don, Don, Don and Don,

>

>It is clear that you have not read ANY of the miner studies which typically 

>follows as the second or third sentence in radon studies with predetermined 

>outcomes ... something like "After cigarette smoking, radon is the second 

>leading cause of lung cancer.  Epidemiological studies of miners and ..... 

>blah, blah, blah."

>

>Do you see one measurement per year or one measurement per 10 years, 50 

>year, etc. as a strength?

>

>Do you see ignoring the influence of silica dust, diesel fumes, and other 

>industrial/mining hazards as a strength?

>

>Before you go any further and quote any more tired references, you might 

>just trot back to BEIR IV, find the miner study references and go read 

>them.  Then tell us all how great the case is for a radon:lung cancer 

>relationship.

>

>v/r

>Michael





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