Re: A question of statistical significance vs operational significance

[epirad@mchsi.com]

Tom,



Thanks for your email. 



If you read Dr. Alavanaja's letter to the editor of the 

American Journal of Epidemiology, you 

will see that he attributes this non statistically 

significant negative finding to poor retrospective radon 

exposure assessment.



 Michael C. R. Alavanja, Jay H. Lubin, Judith A. 

Mahaffey, Ross C. Brownson, Am. J. Epidemiol. 2000 152: 

895-896.



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



Regarding Iowa, the lung cancer rates now mainly reflect 

the relatively low smoking rates in Iowa from 20 years 

ago or so. 



In order to perform a study of NEVER smokers, we would 

need to finish up calibrating the glass-based detectors 

to use for the study.  It is a matter of sample size and 

required power.  We likely could not limit our 

inclussion criteria to those who lived in the current 

home for 20 years as we did for the original Iowa Study 

since it would take too long to recruit subjects.  We 

could propose a study with another state or use glass-

based detectors to estimate past radon exposure. In 

either case, these studies are extremely exspensive and 

it is not easy to get funding for them.



The N. American Pooling of rsidential radon studies  

will hopefully be published in early 2003 and will 

include a large pooling of never smokers.  I am sure 

most funding agencies would like to see this study 

published prior to funding any further residential radon 

studies of never smokers.



Bill Field



> Bill,

> The Missouri I study was negative for lung cancer in nonsmoking women. 

> 

> Alavanja, MC, Residential Radon Exposure and Lung Cancer Among Nonsmoking

> Women, J Nat Cancer Inst, Vol 86, No. 24, 12/21/94

> 

> There have been several other studies involving never smokers that were

> negative. A curious observation is that the Iowa has one of the the highest

> average radon concentrations in the US, but one of the lowest incidences of

> lung cancer, according the SEER Report. It seems Iowa would be a great

> place to study lung cancer etiology in never smokers, of which radon could

> be one of the many factors studied. You've mentioned in previous posts that

> this study is forthcoming.

> 

> Now, what if the EPA is correct and about 18,000 lung cancers per year are

> attributable to radon. BEIR VI states that if every home is reduced to

> below the EPA action level then only about 1/3 of lung (about 6000) cancers

> will go away. Why? Because most of the lung cancer numbers are derived from

> smoking and very small risk values applied to the large number of people in

> the lowest categories. 

> 

> In most case-control studies, most of the lung cancers (about 50%-70%)

> occur in people who are exposed to < 2 pCi/L; and about 70%-90% of the lung

> cancer occur in people with less than 4 pCi/L. Odds ratios cited by authors

> on radon levels above 4 pCi/L are based on very small numbers, sometimes as

> few as 2 or 3 excess cancers. 

> 

> Personally, I think there are very good reasons to be skeptical.

> Tom

> 

> epirad@mchsi.com wrote:

> > 

> > Maury,

> > 

> > You stated,

> > 

> > " When thinking about the increasing weight of

> > evidence favoring beneficial health effects from

> > exposure to low level radiation (such as household

> > radon), I cannot bring myself to get very concerned about

> > the EPA radon campaign."

> > 

> > Maury, other than Dr. Cohen's data, which he himself

> > says does not suggest hormesis (to do so he says would

> > make his findings subject to the ecologic fallacy), can

> > you point me to any well designed study that

> > demonstrates residential radon exposure decreases lung

> > cancer risk?

> > 

> > Please see this reference for my view of this issue:

> > http://www.ntp.org.uk/951-TUD.pdf

> > 

> > Bill Field

> > >

> > >

> > > Bill, thanks for taking the trouble to refer me to relevant data. My

> > > impressions, however, are that you folks are suggesting with an

> > > epidemiological risk factor of 0.5, that out of an annual total lung

> > > cancer

> > > incidence of 157,400 cases, 18,600 or about 12% are attributable to

> > > radon. I

> > > don't believe those radon cases could hope to be distinguished from the

> > > noise

> > > or error variance.  When thinking about the increasing weight of

> > > evidence

> > > favoring beneficial health effects from exposure to low level radiation

> > > (such

> > > as household radon), I cannot bring myself to get very concerned about

> > > the EPA

> > > radon campaign -- except for some of my darker suspicions which already

> > > have

> > > been well-fed over the years by the performance of EPA. I just cannot

> > > view

> > > radon as a threat and I suspect it might even be beneficial to us.

> > > Perhaps my

> > > ignorance, but time will tell after I'm long gone.

> > >

> > > Thanks again for your response to me.

> > > Sincerely,

> > > Maury                   maury@webtexas.com

> > > ================================

> > > epirad@mchsi.com wrote:

> > >

> > > > Maury,

> > > >

> > > > Our direct observations

> > > > http://www.cheec.uiowa.edu/misc/radon.html are in

> > > > agreement with the BEIR VI

> > > > (http://www.epa.gov/iaq/radon/beirvi1.html)projections

> > > > which estimate that approximately 18,600 lung cancer

> > > > deaths each year in the United States are associated

> > > > with prolonged radon progeny exposure.

> > > >

> > > > Bill Field

> > > > > Bill,

> > > > >

> > > > > Would you select an objective, reliable measure of the impact of

> > > > > cancer on human health, e.g., mortality, morbidity, longevity, etc. and

> > > > > tell me what that observation is today in perhaps the US, or the world,

> > > > > or Iowa, or whatever? Then, if we could suddenly cause all radon and its

> > > > >

> > > > > progeny to disappear completely from the earth while all other

> > > > > conditions remain unchanged, what do you see in any hard data, or

> > > > > believe would be the observed effect or change in that selected cancer

> > > > > measurement in, say, 20 years or so?

> > > > > Cheers,

> > > > > Maury Siskel           maury@webtexas.com

> > >

> > > ------------------

> > > It is the soldier, not the campus organizer, who has given us the

> > > freedom to demonstrate.                       Charles M. Province

> > > ************************************************************************

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> 

> -- 

> Thomas Mohaupt, M.S., CHP

> University Radiation Safety Officer

> 

> 104 Health Sciences Bldg

> Wright State University

> Dayton, Ohio 45435

> tom.mohaupt@wright.edu

> (937) 775-2169

> (937) 775-3761 (fax)

> 

> "An investment in knowledge gains the best interest." Ben Franklin

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