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Radon and Smoking (individual vs aggregate)



Dr. Cohen wrote, "If you don't understand that the BEIR Reports use a liinear relationship between lung cancer and radiation exposure, there is no point in discussing these matters with you. What do you think the LNT debate is all about?"



Dr. Cohen, 

If you get a chance, could you respond this the last post. 

I agree, it makes little sense to continue when we are in disagreement over basic facts about BEIR VI.  However, rather than conveying my interpretation of BEIR VI, let me quote:  

 "Miner data clearly indicate that the relationship of lung-cancer occurrence in a person, to cumulative exposure, is not simply linear, and that the joint relationship of radon and smoking is not additive" (Page 376 BEIR VI).  

Relative risks for cumulative radon exposure and lung cancer have dependencies on other factors other then smoking and radon.  There are vectors of covariates that affect background lung cancer rates and other vectors that modify the exposure response relationship. 

Let's take just one example, if you hope to test the LNT theory using an ecologic study, you must know the joint distribution of radon exposure and smoking in EACH county (Guthrie's paper I faxed you goes into detail on how to possibly get at this information).  Nonetheless, you state by using "rigorous mathematics" in your 1995 paper you prove you can test the LNT theory using an ecologic study.  You may have used math, but you needed an assumption that all smokers have the same smoking duration and intensity to obtain the Cohen derived formula.  This faulty assumption invalidates your derived equation.  This faulty assumption can not be later verified or treated by after the fact stratifications using more averaged smoking data especially without knowing the joint distribution of the covariates.  In fact, you have even previously stated, your analysis only,  "crudely introduces the pack-year concept."  Dr. Gilbert has already provided evidence that your results are confounded by smoking, because other smoking related cancers are also negatively associated with your county radon data (Perhaps Jim has a mechanism that shows alpha irradiation to the lung decreases the cancer rates in other organs - if so please share it).  So when you say, the LNT fails, what you are really proving is that the Cohen derived LNT formula that used faulty assumptions failed.  While I am not a loyal LNT supporter, I find myself in agreement with Dr. Piantadosi who said in 1994, your findings do, "more to discredit the analysis than the theory."  I would not expect you to be able to explain your inverse findings by using your "treatments" as you call, since the Cohen derived formula used to test the LNT suffers from faulty assumptions.

Regards, Bill Field




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