RE: TRAB and back to Re: Lung cancer mortality from radon versus ....

["Field, R. William" <bill-field@UIOWA.EDU>]

I logged back onto Radsafe merely to offer a suggestion to Dr. Cohen

concerning how he could improve his ecologic analyses.  But then,

Michael Ford asked in his last post on this subject if I would like to

step in on this different debate.


Posting on these subjects is like getting drug in quick sand surrounded

by alligators.  But, because I have been asked to comment I

will.  Not commenting gives the impression the characterizations

from Mr. Ford are correct.


As I told Michael before, after their letter to then Gov. Bush was

published in the Billett, I received a half dozen emails from that local

Health Physics Chapter asking me to respond to what they perceived as the

misrepresentations of the Iowa Radon Lung Cancer Study in the

letter.  I was sent a copy of the Billet and agreed that the Texas

Radiation Boards (TRAB) letter (which was published in the Billet) did

not present the facts clearly.  I contacted members of the TRAB and

was told Mr. Ford drafted the letter, but it was approved by the whole

TRAB.  I later found out that many of the erroneous statements in

the letter were influenced by postings on Radsafe about the Iowa

Study.  I spoke to Mr. Ford and indicated I did not think that

Radsafe was a scientific forum and a good place to determine the validity

of a study.  It was obvious the TRAB was not going to issue a

correction to their letter so I was left with writing a

letter-to-the-editor of the Billet, which was graciously published. 

To this date, I have not heard any official response from the TRAB

concerning the letter.  I have attached the letter below (I think it

was the last draft), which I sent to the Billet. 


I would be happy to discuss any of the issues by direct email. 

Posting on Radsafe appear to have a life on their own somewhat like the

numerous lives of a cat.

Iowa Radon Lung Cancer Study

Dear Editor,


The October 12, 2000 edition of the

Billet contained a copy of a July 28, 2000 letter written to the

Honorable George W. Bush and signed by Dr. Dale E. Klein on behalf of the

Texas Radiation Advisory Board (TRAB).   In the letter, the

TRAB recommended that the State of Texas challenge the EPA’s proposed

rules in the Safe Drinking Water Act regarding waterborne radon.  As

part of the justification for their position, the TRAB made misleading

allegations about the Iowa Radon Lung Cancer Study.  The Iowa Radon

Lung Cancer Study (1) was a large-scale case-control epidemiology study

that found a statistically significant association between prolonged

residential radon exposure and lung cancer. The study was performed in

Iowa and the participants were women throughout Iowa who lived in their

current home for at least 20 years. The study was funded by the National

Institute of Environmental Health Sciences. 


The TRAB letter contains three erroneous allegations. The first

false allegation was that the Iowa Radon Lung Cancer Study was only able

to establish statistical significance by omitting cases that died during

the study period.  In fact, the study did NOT omit cases

that died during the study period. Analyses were performed on all cases

as well as on the subset of cases that were alive at time of interview.

In addition, contrary to the statement above, the trend in risk (odds

ratio) with increasing cumulative radon exposure was statistically

significant for the categorical analyses for all the subjects.  The

trend analyses for the subset were also statistically significant.

        

The

second false allegation was that the study was only able to establish

statistical significance by carving up the data into non uniform

intervals. In fact, the method used to divide subjects into five

exposure categories was decided upon prior to analyzing any data. This

included the decision to place 15% of the subjects in the highest

exposure category so that there would be an adequate sample size for

analysis. The cumulative radon Working Level Month

(WLM) exposure categories were evenly spaced 

intervals.

        

The

third false allegation was that the study was only able to establish

statistical significance by poorly correcting for disparities in smoking

histories between cases and controls. In fact, the study controlled

for smoking at the level of the individual. Detailed individual smoking

histories were obtained for all cases and controls. The cases’ smoking

histories do not need to match the smoking histories of the controls

since the effect of smoking can be adjusted for using standard

statistical methods. Moreover, misclassification of smoking status would

bias a study’s findings toward no association in the majority of cases.

In order to get a radon dose response relationship attributable to poor

recall of smoking, the misclassification of smoking would have to

correlate with radon exposure. In other words, individuals would have to

independently know their radon concentrations in their home and

increasingly under report their smoking habits as the residential radon

concentrations increase. Since most people in a study were unaware of the

radon concentrations in their home at time of interview, that is a very

unlikely scenario. Other papers supporting the methodologies used in the

Iowa Study are listed below (2-8).  



R. William Field, Ph.D. 

College of Public Health

N222 Oakdale Hall

University of Iowa

Iowa City, Iowa 52245

mailto: bill-field@uiowa.edu

1.      

Field,

R.W., Steck,  D.J., Smith, B.J., Brus, C.P., Neuberger, J.S.,

Fisher, E.F. Platz, C.E., Robinson, R.A, Woolson, R.F., and Lynch,

C.F.  Residential Radon Gas Exposure and Lung Cancer: The Iowa Radon

Lung Cancer Study, American Journal of Epidemiology, 151(11):

1091-1102, 2000.

2.      

Field,

R.W., Steck, D.J., Lynch, C.F., Brus, C.P., Neuberger, J.S., Kross, B.C.,

Residential Radon-222 Exposure and Lung Cancer: Exposure Assessment

Methodology.  Journal of Exposure Analysis and Environmental

Epidemiology, 6(2): 181-195, 1996.

3.      

Field,

R.W., Smith, B.J., Brus, C.P., Lynch, C.F., Neuberger, J.S. and Steck,

D.J.  Retrospective Temporal and Spatial Mobility of Adult Iowa

Women, Risk Analysis: An International Journal, 18(5): 575-584,

1998.

4.      

Fisher,

E.F., Field, R.W., Smith, B.J., Lynch, C.F., Steck, D.J., and Neuberger,

J.S. Spatial Variation of Residential Radon Concentrations: The Iowa

Radon Lung Cancer Study, Health Physics, 75(5): 506-513,

1998.

5.      

Field,

R.W., Lynch, C.F., Steck, D.J. and Fisher, E.F.  Dosimetry Quality

Assurance: The Iowa Residential Radon Lung Cancer Study, Radiation

Protection Dosimetry, 78(4): 295-303, 1998.

6.      

Steck,

D.J., Field, R.W., and Lynch, C.F. Exposure to Atmospheric Radon

(222Rn) in Central North America,

Environmental Health Perspectives, 107(2):123-127, 1999.

7.      

Field,

R.W. , Lynch, C.F., Steck,  D.J.,

Smith, B.J., Brus, C.P., Neuberger, J.S., Woolson, R.F., Fisher, E.F.

Platz, C.E., Robinson, R.A.  Iowa Radon Lung Cancer Study,

Radiation Research, 151:101-103, 1999.

8.      

Field,

R.W. , Steck,  D.J., Smith, B.J.,

Brus, C.P., Neuberger, J.S., Fisher, E.F., and Lynch, C.F. The Iowa Radon

Lung Cancer Study Phase I: Residential Radon Gas Exposure and Lung

Cancer, The Science of the Total Environment, 272: 367-72,

2001.






   



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