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RE: Apparent anti-correlations between geographic radiation and cance r are not surprising
Dan,
Had I expected such an avalanche of messages, I would have abstained...
I agree that no clear conclusion can be drawn from comparing the maps.
What I do not understand is why the "negative image" effect appears to
be so consistent over the all USA territory. If radiation has a very
small influence on cancer incidence, I would have expected randomly
distributed excesses and deficits, without relation, positive or
negative, to radiation levels, that is, neither correlation or
anti-correlation.
Is it conceivable that important health factors known to influence the
risk of cancer (such as education, socio-economic status, medical
coverage, ... ) be consistently correlated with geography, geology and
elevation?
I may be wrong and I welcome explanations.
Sincerely, happy new year.
Philippe Duport
-----Original Message-----
From: owner-radsafe@list.vanderbilt.edu
[mailto:owner-radsafe@list.vanderbilt.edu] On Behalf Of Strom, Daniel J
Sent: January 1, 2003 2:52 PM
To: RADSAFE Listserver (E-mail)
Cc: Strom, Daniel J
Subject: Apparent anti-correlations between geographic radiation and
cance r are not surprising
Philippe DuPort reads way more into cancer and radiation maps than is
warranted. The apparent geographical anti-correlation of radon and gamma
dose rate with lung cancer and all cancers isn't surprising, given that
neither radon nor other background radiation are predominant causes of
lung
cancer or all cancers.
To understand why, let's start with a look at the statistics (as of
about 2
or 3 years ago):
1) There were 552,200 US cancer deaths in 1999
2) There were 2,339,000 US deaths in the period 4/98-3/99
The ratio of these two numbers shows that 23.6% of all deaths in USA
were
due to cancer in 1999.
3) The population of USA was 274,625,507 as of 20:09 EDT Apr 17, 2000.
>From this one can calculate rates:
0.00852 y?1 death rate; one in 117 people die each year
0.00201 y?1 cancer death rate; one in 497 people die of cancer each
year
What proportion of the cancer deaths are attributable to background
radiation and radon decay products? If one assumes
1) 5% per Sv excess fatal cancer rate and a linear nonthreshold dose
response model (EPA's numbers);
2) 0.002 Sv y-1 from background (NCRP's 1987 Report 93 number of
roughly
0.003 Sv/y (300 mrem/y) is too high because the w_lung was used as 0.08,
not
0.12, and preliminary radon data were used); and
3) 75-year life expectancy,
then one calculates a lifetime fatal cancer risk of 0.75% due to
background
radiation including radon decay products in indoor air. Gamma dose rates
from primordial radionuclides make up a small portion of this, so they
would
be expected to contribute very little to explaining variations in cancer
rates.
So, 23.6% of people die of cancer, and radiation under EPA's LNT model
would
account for 0.75% of deaths. Taking the ratio of these two numbers, we
would
expect that variations in radon and other radiation would explain
0.75/23.6
= 0.032 of the variance in all-cancer rates, that is, radiation would be
causative in 3.2% of cancer deaths. This means that there should be a
correlation coefficient (r-square) of 0.032 between background radiation
and
all cancers. The r-square for radon and lung cancer should be higher,
probably around 0.10 or so. It is not surprising that such a small
portion
of the variability in cancer rates due to radiation and radon decay
products
might be masked by other larger risk factors. Strong cancer causative
factors including diet, genetic predisposition, smoking, and lifestyle
factors are also strongly correlated with geography.
However, all geographic effects, radiation or otherwise, are partly
reduced
by migration and immigration.
Because of these factors, epidemiologists don't take so-called
ecological
correlations (e.g., Cohen's county lung cancer rates associated with
county
radon measurements) very seriously, but rather rely on case-control and
cohort study designs.
- Dan Strom
The opinions expressed above, if any, are mine alone and have not been
reviewed or approved by Battelle, the Pacific Northwest National
Laboratory,
or the U.S. Department of Energy.
Daniel J. Strom, Ph.D., CHP
Environmental Technology Division, Pacific Northwest National Laboratory
Mail Stop K3-56, PO BOX 999, Richland, Washington 99352-0999 USA
Overnight: Battelle for the U.S. DOE, 790 6th St., Richland WA 99352
ATTN:
Dan Strom K3-56
Telephone (509) 375-2626 FAX (509) 375-2019 mailto:strom@pnl.gov
Brief Resume: http://www.pnl.gov/bayesian/strom/strombio.htm
Pagemaster for http://www.pnl.gov/bayesian http://qecc.pnl.gov
http://bidug.pnl.gov
-----Original Message-----
From: Philippe Duport [mailto:pduport@uottawa.ca]
Sent: Tuesday, December 31, 2002 12:00 PM
To: Jacobus, John (NIH/OD/ORS); 'Jerry Cohen'; 'Ted Rockwell';
BLHamrick@AOL.COM; 'John Cameron'; radsafe@list.vanderbilt.edu
Subject: RE: Not using LNT to calculate risk does not mean there is no
risk.
John,
Are low doses harmful? The USA all cancers and lung cancer maps are the
negative images of both the gamma radiation and radon maps. Is such a
consistent contrast due to chance alone? One can accept statistical
fluctuations in some states, but in all states? Statisticians, please
tell
us what is the probability for this to be due to chance alone in
virtually
all US states.
John, would agree to live in Denver, with annual doses more than half
the
annual dose limit for radiation workers? Any nuclear facility with such
dose rates lasting for a whole life would be evacuated, don't you think?
Should Denver and all similar places in world be evacuated?
Cancer map:
http://www.dceg.cancer.gov/cgi-bin/atlas/mapview2?direct=acccwm70
<http://www.dceg.cancer.gov/cgi-bin/atlas/mapview2?direct=acccwm70>
Lung cancer map:
http://www.dceg.cancer.gov/atlas/download/pdf2/lun-maps.pdf
<http://www.dceg.cancer.gov/atlas/download/pdf2/lun-maps.pdf>
Gamma radiation map:
http: <http://www.epa.gov/iaq/radon/zonemap.html>
//www.epa.gov/iaq/radon/zonemap.html ;
http://energy.cr.usgs.gov/radon/DDS-9.html
<http://energy.cr.usgs.gov/radon/DDS-9.html>
Radon map:
http://www.epa.gov/iaq/radon/zonemap.html
<http://www.epa.gov/iaq/radon/zonemap.html>
Happy new year to all,
. . .
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