RE: Cohen's Refutation of LNT

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

Jim,


Please try to follow my point here.


 From what I have heard from several of Dr. Colditz's past students, he

does believe the prospective cohort and case-control studies have more

power to assess risk versus an ecologic study.  I think Dr. Cohen

also understands that and has in fact stated that.  That is why Dr.

Cohen tries to justify his use of an ecologic study by saying he is

testing the LNT.  


However, I will email Dr. Colditz and try to get his perspective on this

directly.


But, let me expand my point a bit about criticizing studies without

really looking at their strengths and limitations.  Let me give you

the perfect example from a study I was involved in that I did not feel

was that rigorous (that is why we submitted it as a letter and not a

paper) but it was nonetheless embraced as a great study by some because

of what it found.  If you look at Steve Milloy's Junk Science Page

you will see he has highlighted (as good science) a letter John Neuberger

and I sent to offer at least some preliminary findings that fail to

support the contention that radon causes breast cancer.  Please go

to this site and read our ECOLOGIC paper.


http://www.junkscience.com/news/radon-breast-cancer.html


http://www.junkscience.com/news/radon-breast-cancer2.html 

(copied below from Milloy's site).



At the same time on Milloy's site he has listed Dr. Colditz as a junk

Scientist:

http://www.junkscience.com/roster.html

listing him as a junk scientist for studies like Agent Orange and Spina

Bifida, Red Meat and Bone Fractures, Caffeine and Suicide,

Secondhand Smoke-and-Mirrors,

Weight Gain and Breast Cancer 

which had much more a priori validity than our ecologic study

which Milloy embraced.


Dr. Colditz's studies do NOT deserve such criticism.  Milloy and

others criticizes findings and attacks scientists who publishes findings

that they are not in agreement with.  These attacks are akin to your

generalizations of bottom feeders.  The large majority of the NCRP,

ICRP, and "scientific establishment" are very hard working

scientist who do not deserve such abusive language as "bottom

feeders".    Jim, I only ask you to look at the rigor

of a study and not just whether or not it agrees with your 

view.


Regards, Bill Field

Radon and Breast Cancer

Risk Analysis 1997;16:729-730

A recent letter in Risk Analysis presents an hypothesis concerning

radon (progeny) as a possible risk factor for breast cancer." In

addition to plateout on synthetic clothes-including brassieres-which the

authors discuss, radon is fat soluble and can deliver an internal dose to

breast tissue. (" The authors do not discuss the many risk factors

for breast cancer including family history, high socioeconomic status,

age at pregnancy, and obesity.") These factors can change over time,

thus influencing the reported increase in breast cancer. In addition,

improved case finding can also be a factor in the reported 

increase.

The authors also present a cancer map which shows some positive

qualitative relationship between breast cancer mortality and EPA radon

zones. Mortality is not an adequate indicator of risk for this disease;

incidence data are preferred, but are not available for the entire United

States.

In order to determine the association between radon levels and breast

cancer incidence, we examined data from Iowa, a state with the highest

mean radon screening level and the highest percentage of homes in the

U.S. with radon screening measurements exceeding the EPA guideline of 148

Bq/ml (4 pCi/L). This amounts to 71% of homes exceeding this guideline as

measured in the lowest livable area (unfinished or finished basement or

first floor) using a random survey. The methodology of this analysis was

similar to that described elsewhere.(4)


Population data for White female residents of each county in the state of

Iowa were obtained from the U.S. Census Bureau for the 1980 and 1990

periods. Intercensal estimates were also provided by the census bureau

for the years 1973-1979, 1981-1989, and 1991-1993.

Breast cancer cases were identified through the State Health Registry of

Iowa, a member of the National Cancer Institute's Surveillance,

Epidemiology, and End Results (SEER) Program since 1973. Eligibility was

restricted to newly identified in situ and invasive breast cancers

diagnosed between 1973 and 1993 among 

White female residents of the state of Iowa.


Residential radon data were obtained from randomly selected homes whose

occupants participated in either a joint U.S. Environmental Protection

Agency/ Iowa Department of Public Health radon screening survey conducted

in the first half of 1989. All radon measurements were obtained from a

single detector placed in the lowest livable area of the home during the

winter. Open-faced charcoal canisters were deployed for 2 days at each

site. Radon measurements were assigned to a county using the residential

address. After counties with fewer than ten radon readings were excluded

from the analysis, 77 counties remained out of the original 99.


Age-adjusted breast cancer incidence rates for 1973-1993 were calculated

directly for each of the three groupings of counties. The standard

population was the 1970 U.S. population divided into 5-year age groups.

The 95% confidence interval was then calculated in order to determine

statistical significance. The rates were stratified into low (<8

pCi/L), medium (8-10 pCi/L), and high (>10 pCi/L) radon levels.

Arithmetic mean values of radon were utilized.

Results are presented in Table 1. A total of 32,171 cases are distributed

across 1732 radon readings. Despite an 83% increase in average radon

level, there is no increase in invasive breast cancer risk in the highest

radon counties of Iowa. None of the results were statistically

significant. There was no dose response trend (i.e., no increased risk as

radon levels increased). Separate analysis for in situ breast

cancer revealed identical conclusions.

Table 1. Age-Adjusted Incidence Rates for Invasive Breast Cancers
in 77 Iowa Counties (White females, 1973-1993, stratified by radon levels)

Radon level	Number of counties	Number of radon readings	Average radon reading(a)	Number of breast cancer(b) cases	Breast cancer incidence rates(c)
<8	24	600	6.9	11,357	93.9
8-10	23	545	8.9	9.748	92.2
>10	30	587	12.6	11,066	93.9

(a) pCi/L.
(b) Invasive breast cancer.
(c) Per 100,000 per year. Age adjusted to the 1970 U.S. Standard Population.


It is recognized that descriptive epidemiology is hypothesis-generating and that an analytic design would give more refined data on radon exposure and would include data on other risks factors for breast cancer. An annual average for radon is a preferred measurement compared to a short-term reading (e.g., 2 days). The same comments apply to the letter mentioned above. Regardless, these Iowa data do not support the hypothesis that radon increases the risk of breast cancer.

REFERENCES
P. M. Kildea, Jr. and T. C. Lee, "Radon Plateout on Synthetic Fibers as a Possible Risk Factor in Breast Cancer" (letter), Risk Analysis 16(l), 1-2 (1996).
N. H. Harley and E. S. Robbins, "Rn-222 Alpha Dose to Organs Other Than Lung," Radiation Protection Dosimetry 45(1-4 Suppl.), 619-622 (1992).
J. L. Kelsey, "Breast Cancer Epidemiology: Summary and Future Directions," Epidemiologic- Reviews 15(l), 256-263 (1993).
J. S. Neuberger et al., "Residential Radon Exposure and Lung Cancer: Evidence of an Urban Factor in Iowa," Health Physics 66(3),263-269 (1994).

John S. Neuberger
University of Kansas
School of Medicine

R William Field
University of Iowa
College of Medicine

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