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 Post subject: Is LNT model dead?
PostPosted: Oct 21, 2015 3:55 am 
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A recent study published in the British Medical Journal provides new evidence on risk of cancer from low level ionising radiation.
Risk of cancer from occupational exposure to ionising radiation: retrospective cohort study of workers in France, the United Kingdom, and the United States (INWORKS). http://www.bmj.com/content/351/bmj.h5359


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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 22, 2015 7:05 am 
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Bowspirit wrote:
A recent study published in the British Medical Journal provides new evidence on risk of cancer from low level ionising radiation.
Risk of cancer from occupational exposure to ionising radiation: retrospective cohort study of workers in France, the United Kingdom, and the United States (INWORKS). http://www.bmj.com/content/351/bmj.h5359


Risk of cancer is a fact of life.
Leave LA or NYC for Denver or Salt Lake City.
Higher radiation level.
Yet lower cancer rates.
Why ? I think the lower cancer rates is due to less air pollution not hormesis, but the simple fact that cancer rate isn't higher is telling.
Studies that try to link cancer with nuclear reactors were made in reactors built in reclaimed land from filthy chemical industries, the whole area is contaminated.
Show me a single study that shows higher cancer rates near nuclear reactors build on uncontaminated land.

Then we have the airlines. Airline pilots and cabin crew spend 1000 hours / year at 20x sea level background radiation (35000-41000 ft cosmic ray/solar radiation).
What about the ISS, 100x sea level background radiation for 6 months missions. 100x ! Can we even consider 20uSv/hr low radiation levels ?

It would be dam easy to prove that airline cabin crew have more cancers if LNT were true.
The case for hormesis isn't perfect, but its actually far stronger than LNT.

If reactors caused cancers, there would be a massive pattern of cancers among nuclear workers.

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Last edited by macpacheco on Oct 22, 2015 10:10 am, edited 2 times in total.

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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 22, 2015 8:12 am 
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"The study provides a direct estimate of the association between protracted low dose exposure to ionising radiation and solid cancer mortality."

No it doesn't. What a stupid study. It uses ONLY statistics, which are neither direct nor even scientific.

It has the same fallacies and weaknesses in any statistical study - can't control spurious variables, didn't control for dose rates, didn't control for dose type, etc.

I can show you, with a high confidence interval, a statistical significant correlation between violent crimes and the number of hospitals in a city. Similarly strong correlations exists between the number of ice-cream vans in a city and the number of rape crimes. It does not mean anything.

The study explains that smoking and asbestos are just some of the confounding factors... their claim that lung cancer exclusion somehow covers for smoking is silly, since smoking definitely increases cancer risks other than lung. If the researchers wish to claim that heavy smoking does not increase colon cancer risk, then they are out there with the rest of the pseudo scientists.


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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 22, 2015 8:34 am 
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I continue to be flabbergasted by the conclusions in these silly statistical studies with play-pretend scientists.

Take a look at their graph,

http://static.www.bmj.com/content/bmj/3 ... .large.jpg

This does not suggest a linear relationship at all. The blue line is completely imaginary. The actual datapoints suggest no linearity. The 250 mSv class has lower cancer incidence than all the lower groups. The second and third class have lower cancer incidence than the lowest dose group. This does not suggest linearity at all, it suggests hormesis with a poor dataset (resolution and class division problem).

Then there is the problem of data spread. The data spread just blows up with the higher dose classes and the uncertainty upwards becomes larger whereas the lower bound is always around the zero effect point or even negative. For example the 400+ mSv/mGy class lower data spread extends to well below the zero effect point, how do the researchers explain this? They don't.

Also why did the researchers not bother to, or were perhaps unable to, control for dose rate yet found it necessary to make claims about dose rate (re japan bomb survivor claims).

It is clear that there is a lot more in this data than the researchers bother to look for. In stead they jump to a conclusions that is not supported by their own dataset. The dataset suggest severe resolution problems and poor control of spurious factors, that need to be further investigated.

A lot of claims and conclusions that are simply not supported by their own dataset. This appears to be a trend in these studies, if you know a few things about statistics and start reading a lot of these studies. Most abstracts and conclusions of these type of studies are simply not supported by their own data or are unacceptably oversimplifying their own dataset. It makes you wonder about the researchers motives.


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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 22, 2015 10:49 am 
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I was a bit puzzled by the OP: "Is LNT model dead", and the source study, which appears to suggest that the LNT model applies.

However, as Cyril points out, it's not really a linear relationship, and I don't think you can draw conclusions from it.

For example, from the chart, if you are subjected to a cumulative dose of 175mGy, then make dammed sure you expose yourself to get the cumulative does up to 240mGy. This will even reduce your risk of cancer compared to no dose.

What would also be useful would be to separate out whether the doses were received in one hit (ie an accident or specific event) of gradually. I would for example hypothesize that 20mS received in one shift might be dangerous, whereas 20mS received over the year (0.1mS per day on site) would not be.


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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 22, 2015 12:03 pm 
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Cyril R wrote:
I continue to be flabbergasted by the conclusions in these silly statistical studies with play-pretend scientists.

Take a look at their graph,

http://static.www.bmj.com/content/bmj/3 ... .large.jpg

This does not suggest a linear relationship at all. The blue line is completely imaginary. The actual datapoints suggest no linearity. The 250 mSv class has lower cancer incidence than all the lower groups. The second and third class have lower cancer incidence than the lowest dose group. This does not suggest linearity at all, it suggests hormesis with a poor dataset (resolution and class division problem).

Then there is the problem of data spread. The data spread just blows up with the higher dose classes and the uncertainty upwards becomes larger whereas the lower bound is always around the zero effect point or even negative. For example the 400+ mSv/mGy class lower data spread extends to well below the zero effect point, how do the researchers explain this? They don't.

Also why did the researchers not bother to, or were perhaps unable to, control for dose rate yet found it necessary to make claims about dose rate (re japan bomb survivor claims).

It is clear that there is a lot more in this data than the researchers bother to look for. In stead they jump to a conclusions that is not supported by their own dataset. The dataset suggest severe resolution problems and poor control of spurious factors, that need to be further investigated.

A lot of claims and conclusions that are simply not supported by their own dataset. This appears to be a trend in these studies, if you know a few things about statistics and start reading a lot of these studies. Most abstracts and conclusions of these type of studies are simply not supported by their own data or are unacceptably oversimplifying their own dataset. It makes you wonder about the researchers motives.


In a subject as complicated as this one has to keep an open mind. I did not mean polemicize, but only report the existence of a wide-ranging study like this. I know that statistics can be tweaked (biased) to provide preconceived results. However, the statistics are almost the only tool that can be used to validate one or another theory in this matter.

One major drawback of this study is that dataset seems not to be available to other scientists, it is deposited in Lyon, France due to individual privacy issues. "Data sharing: For reasons of ethics and permissions from different agencies, the data are maintained at the International Agency for Research on Cancer (Lyon, France); it is not possible to send the data outside of the agency. " Is this a credible reason? Aren't there ways to anonimize the dataset? I really don't know, I am not a lawyer.

I agree with your comments on the poor curve fitting to few data points. And more: Why are they grouped this way, instead of having a true cloud of individual data? Ok, I know the answer, it is because of the low number of high exposition data, but there should be a less weird way to re-balance them.


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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 22, 2015 12:53 pm 
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macpacheco wrote:

Then we have the airlines. Airline pilots and cabin crew spend 1000 hours / year at 20x sea level background radiation (35000-41000 ft cosmic ray/solar radiation).

It would be dam easy to prove that airline cabin crew have more cancers if LNT were true.

Good point. Is there any study on this cohort? There should be a measurable 5% increase in cancer if LNT were true (when they were child they did not flight). Nevertheless, smoking is not allowed while in flying. One should watch for smoking/not smoking or indirectly for EPOC prevalence to isolate the sample for less smoking. On the other side, Is food served while in flight more or less cancerogenic than average?


Last edited by Bowspirit on Oct 22, 2015 1:00 pm, edited 1 time in total.

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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 22, 2015 12:56 pm 
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Quote:
Why are they grouped this way, instead of having a true cloud of individual data? Ok, I know the answer, it is because of the low number of high exposition data, but there should be a less weird way to re-balance them.


Grouping is inherently suspicious, because
1. there is no need for it
2. grouping is arbitrary

Put 2 together and you have a hidden agenda. You can use a few groups and change the division such that it supports any predetermined conclusion.

if you have thousands of data points, then use that and don't bin. Then you have a much more useful point cloud.

In stead what we end up with is a vague grouping with no clear explanation of the major discrepancies from LNT. Hardly "direct evidence" as the researchers claim.

It just has suspicious written all over it.


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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 22, 2015 1:05 pm 
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I should point out an important fact about nuclear worker exposure. In most cases, there is nil dose most of the time, but then there are odd repair, inspection, or refueling jobs that may incur multiple mSv in minutes or a few hours. Point is, it is typically not low dose rate, even though it is spread over many years, most of the time the dose that workers receive is just background.

Now if the researchers knew the dose rate. That would be useful. One can then do filtering analysis types, such as ignoring the first 1 mSv/day and then seeing if the curve fit to linear (or other curve) becomes better. One can also check what the cancer incidence is for workers that never received more than 1, 2, 3, ... n mSv/day. That would be enormously more useful than fudging conclusions from faulty binned data.


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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 22, 2015 5:19 pm 
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LowDose Rads cause Leukemia
Exactly like
Health Care causes Cancer.

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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 23, 2015 7:58 am 
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alexterrell wrote:
What would also be useful would be to separate out whether the doses were received in one hit (ie an accident or specific event) of gradually. I would for example hypothesize that 20mS received in one shift might be dangerous, whereas 20mS received over the year (0.1mS per day on site) would not be.


That's well said, it would also be my hypothesis, its odd that there is so little control for this in any study, especially considering how bloody obvious it is. Everyone simply assumes that if you know the cumulative dose is X, then you can infer Y number of cancers in Z population.

Perhaps the most absurd artifact of LNT, the "collective dose" theory has become so engrained that even researchers in the field can't see the forest for the trees anymore. It is very sad to see such things happen, when professional researchers in the field jump to predetermined conclusions rather than admitting their data doesn't support their predetermined notions and actually suggests much more complicated things going on. I guess if you are a hammer, everything really does look like a nail.


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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 23, 2015 7:15 pm 
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I think the actual values are 100mSv acute and ~25µSv/h.
This leads me to support the LED model wherein the effective dose is the integration of any dose in excess of 12.5µSv/h and that effective dose that exceeds 50mSv is put into the LNT equation for ERR.

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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 26, 2015 2:38 am 
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This may be a simplistic analogy, but far and away the most lethal radiation - in terms of total deaths - is UV from sunlight.

If a European sunbathes for 10 min every day in Dubai for a month, they'll be OK. That is 5 hours of exposure. If he/she sunbathes for 5 hours in one go, it's a hospital admission with greatly increased skin cancer rates.

Whilst the radiation, ionization mechanisms and organs are different, the body's mechanisms for repair are similar in both cases. If LNT applies to nuclear radiation, it should also apply to UV radiation.


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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 26, 2015 9:05 am 
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alexterrell wrote:
This may be a simplistic analogy, but far and away the most lethal radiation - in terms of total deaths - is UV from sunlight.

If a European sunbathes for 10 min every day in Dubai for a month, they'll be OK. That is 5 hours of exposure. If he/she sunbathes for 5 hours in one go, it's a hospital admission with greatly increased skin cancer rates.

Whilst the radiation, ionization mechanisms and organs are different, the body's mechanisms for repair are similar in both cases. If LNT applies to nuclear radiation, it should also apply to UV radiation.


In fact, UV is ionizing radiation, and it definitely is nuclear since it comes from a giant nuclear reactor. Its odd that the solar people like to claim the 150 million km safety distance makes up for it. Thinking that 150 million km of vacuum is a good radiation shield shows us how much these people know.


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 Post subject: Re: Is LNT model dead?
PostPosted: Oct 26, 2015 9:13 am 
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KitemanSA wrote:
I think the actual values are 100mSv acute and ~25µSv/h.
This leads me to support the LED model wherein the effective dose is the integration of any dose in excess of 12.5µSv/h and that effective dose that exceeds 50mSv is put into the LNT equation for ERR.


Very interesting figures, thanks Kite.

What is the basis for these numbers? 25µSv/h is 0.6 mSv/day, much lower than the experiments I've seen. The lowest radiation beagle dogs were 3 mSv/day, no increase in cancer but a 5% reduction in life expectancy. Below 3 mSv/day there is little experimental data.

Where does the 12.5 µSv/h come from? Is it just a safety factor of 2 thing?

Also is there really proof that 50 mSv or 100 mSv prompt dose has no real bad health effects? I mean, if a million people each received a medical scan of 100 mSv worth, surely there would be some detectable health effect?

I'd be fine with a population risk model that ignores the first 25 µSv/h and treats everything over cumulatively a la LNT. That would solve the biggest concern I have with LNT, the overexaggeration of health effects of tiny doses at low dose rates, over large populations.


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