Re: Radon Health Risks

[hflong@postoffice.pacbell.net]

Rad health wrote:



> Howard Long,

>

> Your email below is really incomprehensible.

>

> Comparing selection to sin??

> >> Yes, "Thou shalt not bear false witness" (as selection does) HL



> The Iowa study selected lung cancer cases from the SEER registry with the

> requirement that they lived in their current home for at least 20 years

> Nothing sinful about that.

> >>Agreed. HL



> The selection criteria to match cases to controls were by age (5 -year age

> groups), gender, and residency requirement.  They randomly selected controls,

> by 5 year age groups, from Drivers Lic. files and Medicare files.



>> THERE!  Selection by age ("one cause" of cancer)

but NOT  BY SMOKING destroys the matching of controls, (struggled for in

double-blind placebo trials). To ignore such a dominating cause of lung cancer,

or to merely extrapolate from other studies ("adjust"), destroys essential

matching. Why not find controls that matched for smoking? . HL



Again nothing sinful about this.  If they would have matched completely on

smoking status and as Dr. Field has said, he does not think this is possible, it

would no longer have been a population based study.  In the paper which I doubt

you ever read, it says the results are most generalizable to women in the upper

midwest.



>>>That "restriction to upper midwest women" was not stated in the American

Cancer Society article,"Radon Causes Lung Cancer"!

Will Professor Field please ask the editor to correct the omission?HL



> By the way, age is an effect modifier.  Changes occur within the body with

> age, but age itself never killed anyone.  Correlation between age and death

> rate does not equal causality.  In fact, age adjusted lung cancers go down in

> those over 70 years of age.  Black women and men also have much higher

> lung cancer rates that white men and women.

>

> It is impossible to have subjects equal in all aspects under study and if  you

> did that would be over matching.



>>>>"OVERMATCHING?" What do you think placebo trials are for?! (Answer: to

obtain the closest matching possible, in all respects other than that tested in

the null hypothesis)



> We have some space for an extra graduate student in epidemiology, are you

> interested?  Are you an M.D.?



>>>Indoctrination is not education. Independent thought requires a free market.

I just passed my Family Practice Board exam for the 5th time. I am paid by

thousands of satisfied patients - not funding requiring politically correct

conclusions ( like public health).

Howard Long MD MPH



> Don Smith

>

> >Selection is sin in epidemiology - and we all sin. Our rationalizations are

> >minimized by double-blind, placebo-controlled, prospective studies, >repeated

> by disbelievers.

> >

> >However, such a definitive experiment is difficult with home radon. So, Field

> matched controls for age (one cause of lung cancer) - but, >statistically

> "adjusted" for smoking (another cause of lung cancer).  Only 32% of  Iowa

> "controls" smoked, vs 86% of cases. Such extrapolation, ie, extension beyond

> the data at hand, assumes applicability of data from other studies, other

> populations. Extrapolation also derived LNT. One extrapolation in support of

> another, stretches credibility.

> >

> >Also, selection of Iowa location (for whatever reasons) may disqualify

> inference to other parts of the USA. Iowa women were a 1% outlier in Cohen's

> >mortality study. His variation within is small, with very short 1 SD bars (18

> at 1/4 pCi/l intervals),  and variation without is great (below 1 pCi/l vs

> above, or regression of same).



> The assumption of all epidemiology (and case-control) is that, despite

> universal uniqueness, residual unknowns can be

> reasonably dismissed by having subjects virtually identical in all respects

> except that under study. Infering to the whole from a part known to be

> different, is taboo - no matter how convenient.

> >

> >We need a definitive study.

> >

> >Howard Long (MD MPH epidemiology)

> >

> >Rad health wrote:

> >

>

> _________________________________________________________________

> Chat with friends online, try MSN Messenger: http://messenger.msn.com



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