[ RadSafe ] Increase in cancer in Sweden can be traced toChernobyl

Sat Jun 2 15:35:17 CDT 2007

It seems to me that they did an intensive work, linking each cohort member (about 1100000 cohort members)to environmental radiation measurements. Yet it is an ecological study, a "high resolution ecological study" indeed, with the limitations of an ecological study.
They did not use the "breakdown" trick. The increase in risk was significant only to total cancer morbidity.
There was an interesting finding. They divided the follow up years, 1988 to 1999, to three periods . the risk was the highest in the early period after the Chernobyl accident, and it was lower in the last period. I would expect (based on the LSS experience)just the opposite. One explanation may be screening and early detection effect. If I am right then an extended follow up period will result in further decrease in cancer risk.
Dov Brickner   MD
Berr-Sheva ISRAEL

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf Of Brennan, Mike (DOH)
Sent: Friday, June 01, 2007 6:44 PM
To: radsafe at radlab.nl
Subject: RE: [ RadSafe ] Increase in cancer in Sweden can be traced toChernobyl

It would be interesting to see how the study was conducted and what the raw data looked like.  Off hand I can remember other "studies" that found "statistically significant" increases do to whatever the researcher chose to believe was the cause.

The easiest is data pruning: you don't have enough resources to do a detailed examination of all of the effected area over the entire time span, so you concentrate on those places and/or times where a quick scan of the data shows you will get your best result.  It is amazing how few zeros you need to exclude from the mix before the average starts to go up.

Another fun way of getting the results you want is to get a breakdown of all the cancer types that are tracked, and then look closely only at those that show an increase.  This works particularly well when you track some rare types where one additional case can be a 100% increase.

In connection with Chernobyl and its effect in the far North there is a factor that would be difficult, perhaps impossible to account for.  In response to Chernobyl a lot more attention was focused on a population that was primarily rural, and some 10% nomadic reindeer herders.  Then Swedish government, in one of those wrong-headed panic moves so typical of responses to radiation issues, confiscated and slaughtered most of the reindeer, because they were eating fallout contaminated vegetation.  The nomads went from living independent active lives to living in settlements, subsisting on the dole.  Between the increased ability of satiations to count illnesses and the effect of lifestyle change (diet and physical activity) and stress it would be difficult say what a true background rate of illnesses, including cancer, would be.  And without a background rate it is hard to know if one is seeing an actual increase.

I am not saying that there has been no cancer increase in connection with Chernobyl.  I am saying that the more confident a researcher is that he has found "a small but statistically significant increase" in cancer rates and that he know just where it came from, the less confident I am that the researcher is actually letting the data speak for itself.

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf Of Jim Hoerner
Sent: Thursday, May 31, 2007 5:54 PM
To: Know_Nukes at yahoogroups.com
Cc: radsafe at radlab.nl
Subject: [ RadSafe ] Increase in cancer in Sweden can be traced to Chernobyl

Increase in cancer in Sweden can be traced to Chernobyl

The incidence of cancer in northern Sweden increased following the accident at the nuclear power plant in Chernobyl in 1986. This was the finding of a much-debated study from Linköping University in Sweden from 2004.

Was the increase in cancer caused by the radioactive fallout from Chernobyl or could it be explained by other circumstances? New research from Linköping University provides scientific support for the Chernobyl connection.

"This issue is important because the indicated increased risk may come to influence the prevailing exposure limits for the population. Enhanced knowledge of the risks entailed by radioactive radiation is key to work for radiation safety and makes it possible to prevent diseases," says Martin Tondel, a physician and researcher in environmental medicine who will soon be defending his doctoral dissertation Malignancies in Sweden after the Chernobyl Accident in 1986.

In two studies using different methods, Martin Tondel has shown a small but statistically significant increase in the incidence of cancer in northern Sweden, where the fallout of radioactive cesium 137 was at its most intense.

The cancer risk increased with rising fallout intensity: up to a 20-percent increase in the highest of six categories. This means that 3.8 percent of the cancer cases up to 1999 can be ascribed to the fallout. This increased risk, in turn, is 26 times higher than the latest risk estimate for the survivors of the atom bombs in Hiroshima and Nagasaki, whose exposure was many times higher.

[This is not credible, IMO.  Someone needs to scrutinize this work, please. 
- JH]

The increase in Tondel's studies came a remarkably short time after the disaster, since it is usually assumed that it takes decades for cancer to develop. The dissertation discusses the interpretation of the research findings from the perspective of the theory of science.

The conclusion is that there is scientific support for a connection between the radioactive fallout and the increase in the number of cancer cases.  
[That IS credible. - JH]

Source: Linköping University

http://www.physorg.com/printnews.php?newsid=99758918

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