Neural network analysis “unequivocally” reveals threshold dose response in atomic bomb victims
Low dose radiation suppresses cancer.
Note: Low dose in this case is defined as being below a threshold value of somewhere between 100 – 200 mSv depending on exposed organ.
That bold, conventional wisdom-challenging statement is supported by an incredibly important paper titled Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors published in the Journal of Radiation Research. It first appeared in an online version in December 2013.
Somehow, I missed the dramatic headlines about this paper and its paradigm-shattering conclusions; I’m sure they must have been all over the news media.
Maybe not. Perhaps the paper’s authors (Masao S. Sasaki, Akira Tachibana, and Shunichi Takeda) neglected to hire publicists, issue press releases and appear on syndicated talk shows.
Here is a quote from the Perspectives section of the paper.
Due largely to a limited statistical power at low doses in A-bomb survivors, cancer risk is often expediently correlated linearly with dose down to zero dose without threshold and expressed on a ‘per-Sv’ basis. The application of the ANN method developed here circumvents this difficulty and unequivocally demonstrates for the first time the presence of a threshold of excess relative risk in humans exposed to ionizing radiation. However, the threshold was fundamentally different from that of the canonical definition of zero effect until the dose reached a critical point, but instead it was manifested as a reduction of background cancer rate.
(Emphasis joyously added.)
Read that again.
Not only did the statistical analysis of existing data reveal the presence of a threshold, but it showed that doses below the threshold suppressed cancer. Instead of being “conservative” by assuming that there is no such thing as a safe dose of radiation, it is far more likely that 60 years worth of regulations and effort to keep doses As Low As Reasonably Achievable based on a consensus of accepting a linear, no-threshold dose response assumption has led to an uncountable number of extra cancers.
Those cancers might have been suppressed if only scientists and regulators had earlier access to modern data and statistical tools and learned that they should be prescribing health-enhancing moderate radiation doses all along.
PS: Here is the paper’s copyright statement:
© The Author 2013. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
That kind of copyright statement needs to be encouraged.
I saw this when it came out, and if I had any idea you hadn’t seen it I would have notified you.
Note also that we are talking about prompt doses here, not extended doses, for which the threshold is certainly higher.
“Throwin’ mud ain’t arguin’ ” Mark Twain
This is using the result of the very study on which almost all of the LNT claims are based. So if this is cherry-picking, then all of LNT also is.
I don’t argue with creationists, climate change deniers, LNT deniers, etc.
Science denial is simply that. A pathology.
Bob – You are once again treading on thin ice. If you have an argument that is not name calling, please share it. Otherwise stop commenting.
Did you even bother to read the linked paper and discern its source before you starting flinging dirt?
“Did you even bother to read the linked paper and discern its source before you starting flinging dirt?”
That is a key question, that I suspect I know the answer to.
Bob, do you actually know what “science” is?
Don’t worry, Bob. As a creationist (see Pope Francis’ recent speech to the Pontifical Academy of Sciences), a skeptic of anthropogenic global warming (dumping trash into the atmosphere is an untried experiment and stupid but may not necessarily cause AGW), and an LNT denier (but I do believe in radiation hormesis), I have zero desire to argue with you and your kind. You’re wrong. Period. Truth is truth, not determined by consensus or democratic vote, and you are not on truth’s side.
“I don’t argue with creationists, climate change deniers, LNT deniers, etc.”
Bob, I need to ask, then why are you here? Why isn’t the above statement the equivalent of saying “don’t confuse me with the facts, my mind is already made up?”
I think your audience deserves a better response than what you chose to give.
Perhaps LNT exists for some tissues (such as the lens of the eye) but not others. Tissues with no blood supply will have a difficult time repairing themselves. An optics course that I took in the 1970’s involved a field trip to an optometrists office. The Dr. Said he had an 85 year old woman with 20/15 vision! Perhaps the ozone layer was in better shape then, which would have offered more protection from uv radiation.
I think this is what I was asking you about a few days/weeks back on twitter.
Definitely someone posted something new debunking LNT. I still can’t remember who it was, or can I find the original tweet.
Something about a J shaped curve.
This might be it.
Great! Thanks! 🙂
I think the one you remembered describing J-shaped curves is more likely to be this one “Cancer Control Related to Stimulation of Immunity by Low-Dose Radiation” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2477702/
I’ve been reading some of the posts here.
Its a pity that many here forget the basis of LNT.
LNT is an EXTRAPOLATION of an incomplete data set at the low end.
Hence, it is NOT science. But rather an attempt to err on the side of caution.
Fine for that.
Wrong when it is being passed along as fact for other purposes.
At best, LNT is an assumption.
Mark, it’s mostly Bob Applebaum who is denying this. He keeps trying to describe as a scientific consensus on LNT what is actually nothing more than a regulatory, precautionary approach consensus about a range where the scientific consensus is that we *don’t know* what the effect is exactly. And even that regulatory, precautionary approach consensus doesn’t actually exist anymore as both UNSCEAR and WHO are more and more of the opinion that at a low dose for a large population it hurts much more than it helps.
But yes, some here made the error of accepting his claim that such a scientific consensus exist, and then tried to demonstrate it’s a wrong consensus, when actually that pretended consensus is just a fable.
Rod – thanks for this post and the link to a very important paper. After a first look at the paper, what caught my eye was this paragraph towards the end:
The authors provide multiple citations for these statements, and go on to speculate on the mechanisms behind radio-adaptive response, again supported by multiple citations. The statement that radio-adaptive response protects against chemical induced tumors and chemical genotoxins. I think this point has to be made more strongly – the radio-adaptive response doesn’t just protect against radiation exposures. It’s no magic bullet, but could be an important adjunct to public health.
If these researchers have some evidence to present they should do so. Speculating on vague and unspecific results (allowing for “considerable variability”) and suggesting they are “reminiscent” of other results is very imprecise (if not highly problematical). Allowing for considerable variability in dose estimates should make a lot of things possible … the “unequivocal” basis of these results is not going to be one of them.
Using this statistical model, there was a heightening of risk in Nagasaki (which is not explained) and organ and gender variability regarding appearance (and lack thereof) of a threshold. The paper does not provide an explanation for threshold in some groups and some organs and types of cancer of the study population: “The biological mechanism behind this threshold response is unclear” (p. 389). The variability of the result is not explained or investigated (but speculations are offered on confounders, sampling bias, internal deposition of alpha particles, repair mechanisms, and more).
Paper seems a bit unfocused and rather inconclusive. The two cities and study populations have different results, and as long as you are not concerned with colorectal and thyroid cancers in men or women, oral cancer in males (in which no threshold was present), liquid, cervical and breast cancer (and reside in Nagasaki) these results appear consistent. That’s a lot to ignore. In their conclusions, they focus on “vast individual variability” and warn against revising radio protection standards away from precautionary principle (and thus underestimating risk for different groups, especially youth, those in general good health, and populations exposed to high-LET radiation).
“Unequivocal” is clearly in eyes of beholder.
One of the benefits of our modern age is our ability to communicate rapidly. That gives us the ability to engage in a more distributed review process. The paper referenced in this article is published in its entirety. In essence, it is a statistical reanalysis of a widely available data set using modern tools. For people with the right training and interest, it is completely reproducible or falsifiable.
Have at it.
I already did … the results are highly inconsistent (and the authors do not have an explanation for this). This is clearly stated in the paper. “The biological mechanism behind this threshold response is unclear” (p. 389). They have some speculation on what is deriving the variability in their result (but no clear or consistent answers). Just some possibilities. There is no way in this study to combine the results from the two cities and get a consistent result: “A significant difference in dose–response pattern between the two cities of Hiroshima and Nagasaki at low doses may give rise to a problem in the use of combined two-city data for risk projection extrapolated to the general population.”
If the authors wish to suggest this result is “unequivocal” they have done a very poor job showing it.
The paper was not written by radiobiologists. It is a statistical/mathematical paper probably written by epidemiologists.
For a good explanation of the biological mechanisms behind the threshold response, I highly recommend Feinendegen’s “Hormesis by Low Dose Radiation Effects: Low-Dose Cancer Risk Modeling Must Recognize Up-Regulation of Protection” Therapeutic Nuclear Medicine Springer 2012 ISBN 978-3-540-36718-5.
The paper is important because it is part of a reasonable, logical, consistent explanation that supports observed results of the actual response of the organisms of interest (humans) to low dose radiation.
It is not a clever, untestable fabrication created by competitors based on selective reporting of experiments on fruit flies. It was designed to reveal truth, not to continue the steadily funded effort to spread FUD about nuclear energy in order to maintain petroleum’s share of the global energy market.
“The biological mechanism behind this threshold response is unclear”
Did you really just quote that EL as a criticism ??
LNT as a conclusive model has no corresponding illustrative biological mechanism OR real experimental or observational backing.
Good point! EL is so internally inconsistent it’s funny if you pay attention to it.
We are supposed to come up with biological mechanisms, even though LNT has no interest or justifications here whatsoever. LNT is only interested in statistics.
There are actually many good biological mechanisms that we know of. Anything from protein repair to adaptive stimulation, etc etc.
The mechanisms are not strange and are the rule in biology. When you do sports excercise, it damages muscle tissue. But the biological effects are well known and benefifical as muscle tissue is stimulated by straining it. Same for the bones (big problem for astronauts, no strain on the bones from zero gravity means no stimulus means bone breakdown). Same for the teeth.
It would be hard to find a biological area where there aren’t stimulating effects at low doses.
It is LNT that must come up with a biological explanation why 1 mSv/day for a year is the same as 365 mSv in one second each year. It is LNT that must come up with a biological explanation, backed up with statistical proof, that 1 billion people receiving 1 mSv is the same biological effect as 1 million people receiving 1000 mSv.
LNT is no science, there is no biological theory behind it, it flat out denies biological repair mechanisms and even the existence of certain proteins, it denies many human and animal studies that clearly can’t support LNT. Claiming that drinking 365 glasses of beer on one day is the same as 1 glass a day for a year is silly but that is what LNT claims.
Statistics isn’t science. Biology is science. Statistics is at best a useful extra tool to employ to see that controlled lab tests with sound biological theoretical model, are correct. Even then the tool is of little use when there are such low signal to noise ratios as there are in low dose radiation research.
When your results are all over the map (e.g., one population shows threshold in one city and not in another, one type of cancer in one population but not another, one age or gender group in one cohort but not another), you should have at least something remotely concrete to hang your hat on (and not a bunch of random speculations). Wouldn’t you think? In cases where there are no “stimulating effects” as you describe them (but an elevated risk), what has happened here? Do universal biological mechanisms take a holiday (as appears to be the case in these instances)? Have folks here even read this vague and imprecise paper?
LNT seems fine down to <0.2 Sv, and then there is uncertainty (and a variety of complicated biological and environmental interactions that take place). How folks from different environments, age groups, gender, lifestyle, exposure categories, health pre-condition, etc., respond to such sources of physical and toxic stress appears to be highly variable (or "vastly" variable as the authors describe it). These are the specific and concrete findings highlighted in the paper. Pointing to a few speculations that haven't been tested or statistically modeled in the study (and other avenues for future research) doesn't change this fundamental fact.
You might want to look more closely at what the authors specifically recommend about a precautionary principle and transferring risk across populations before getting all excited about so called "universal" biological mechanisms and whether LNT (based on the findings in this paper) needs a significant re-write or not.
The “precautionary principle” should not be applied to something like radiation. We have 115 years worth of experience in which we were aware of being exposed and all of human history in which we know we must have been exposed.
Precautionary principle assumes that there is no risk at all from NOT exposing anyone, but the “vastly variable” results that you are dismissing still lead to the conclusion of overall benefit to a large population from moderate radiation exposures. The utilitarian in me says it is completely unfair to society to make a choice that would increase overall suffering.
Feel free to remain fearful of radiation and proclaim “there is no safe dose.” You are on the fringes and advocating an increase in society harm by ignoring science.
EL the biological mechanisms are well known and much other research including real lab tests on various animals, data on radium dial painters, breast cancer etc etc all support this sound biological and statistical framework. Please see presentation from Dr. Jerry Cuttler:
” Do universal biological mechanisms take a holiday (as appears to be the case in these instances)?”
No EL you are confounding the facts again and use isolated statements that bear no relevance to the main theme.
Let us consider the facts.
1. Bomb exposure is prompt and overwhelms all biological repair mechanisms. Prompt exposure is of little relevance to hormesis.
2. Statistics is not science. Biology is science.
3 Cancer is a common affliction and there are natural variations depending on local food use, local customs, local air quality differences etc etc. A lot of noise and not a lot of signal if the dose is low. This means you can dredge any conclusion from this data that you want.
“LNT seems fine down to <0.2 Sv, "
No EL it is not fine down to 0.2 Sv. It is fine for prompt exposures down to 0.2 Sv and these bear no relevance to the actual risks of nuclear energy technology. Nuclear energy risks are chronic which is a different beast entirely. With chronic doses there is much evidence of no bad health effects and many positive effects up to 2 mSv/day of low LET radiation. The total dose isn't relevant at all, its the dose rate. 10 years of 2 mSv/day is 3.65 Sv but is no health hazard.
Using prompt exposures to prove LNT is silly. LNT and hormesis are not much different for prompt exposures because hormesis is about biological responses which are not prompt (typical time constants would be in the 12 to 48 hour range for biological response).
LNT true believers have used prompt exposure, high dose exposures to assert that LNT is correct and then extended this as if it were linearly true for chronic exposures of 10 to 1000 billion times lower dose rates. This is like saying, we've seen that taking 365 pills of aspirin is very bad for health, so taking 1 pill a day for a year must logically be very bad for health. The box of aspirin does not have a limit on the yearly intake, it has a limit per 6 hours. Why do you think this is so EL?
LNT people continue to discourage discussion on hormesis by looking at prompt exposures and dose rates per year. They should be looking at chronic exposures and dose rates per day to discuss hormesis. But they don't because they are clueless about biology and the difference between chronic and prompt exposure.
You’re aware this is a preposterous claim … correct?
If you can find any support from it (from any credible source) please suggest where we may look. Otherwise, it seems pretty clear to me you are way down the rabbit hole, and have little reasonable (or scientifically supported) to say on the topic.
Not at all. 2 mSv/day is within the tolerance limits established by both the NCRP and the ICRP in 1934. No negative heath effects have ever been detected for a group of people whose chronic exposures remained below that limit.
Of course it has. Your statement is contradicted by most available research on the topic. It is unclear to me why a dose limit from 1934 has any meaning to you (specifically addressed not to genetic impacts, but injuries to superficial tissues, changes in blood, and derangement of internal organs)? It has been significantly revised for some 60 years (largely due to “incomplete evidence on which” it was based, greater awareness of cumulative and irreversible health impacts of radiation at low and moderate doses, and recognition of the need to protect workers and the general public from expanded use of radioactive sources, including those of nuclear power).
El you are so wrong. Check the jerry cuttler work for example:
Not true. The radiation dose model was changed from the established threshold model to the linear no-threshold dose assumption based on a focused effort by eugenicists working with grants provided by the Rockefeller Foundation.
Focus on what I said – no negative health effects have ever been detected.
The “genetic” changes Muller and his allies were supposedly trying to prevent were not measured; they were invented out of whole cloth and rather cleverly described as something that we would never be able to find because the effects of the “mutated” genes might show up in distant future generations. The calculated injuries were made to look large and scary because they were supposed to occur with some minute probability on a very large population that included not only those people living today, but those that will be born hundreds of years in the future.
I keep reading the history – like the ICRP document to which you linked – and finding statements like this one regarding the state of knowledge in the 1950s.
Calabrese has uncovered and documented exactly what that research conducted on experimental organisms actually showed. (Ref: Key Studies Used to Support Cancer Risk Assessment Questioned Environmental and Molecular Mutagenesis 00:000^000 (2011))
Hermann Muller began making his claims about genetic effects based on x-ray exposures to Drosophila in 1926 at the University of Texas. The lowest doses he used were 400 R. He made claims about low dose radiation effects for twenty years, but never did any experiments at any lower doses.
In 1946, he was scheduled to receive a Nobel Prize for his 1920s work.
About a month before his speech, he received experimental results from Caspari and Stern that was actually measuring effects at lower doses instead of assuming a straight line. That experimental data showed that the mutation effects disappeared at doses that were still relatively high by todays ALARA standard and even above the tolerance dose established for humans in 1934. Despite having that information several weeks before receiving his prize, Muller the following statement during his Nobel Prize speech.
He then worked to cover up the results that his own colleagues had provided.
Since reading Calabrese’s well documented papers, I have found additional information available from sources like biographies published by the NAS and contemporary articles published in the New York Times and Time Magazine showing the kind of PR effort that went along with the replacement of the threshold dose model with the LNT assumption.
With the strong backing of Muller’s decades-long funding source — the Rockefeller Foundation — which was the same foundation that initially funded the radiation studies of fruit flies, suggested that the NAS should study radiation health effects, funded the NAS BEAR committee from 1955-1962, funded at least half of the members of the genetics committee and provided the chairman of the genetics committee for BEAR 1 (Warren Weaver), his assumptions became the basis for most of the papers to which you like to refer.
How are you counting to come up with your assertion about the contradictions of “most available research?” I will grant that most available regulatory bodies might currently disagree, but the articles I have been posting are reports about the efforts of a large number of qualified researchers who have published a body of peer reviewed science that supports my statements.
I’m not making this stuff up, and I am not stubbornly clinging to politicized publications that are often years to decades old.
BEIR VII, for example, was published in 2006 based on research that was mostly completed before 2000. Even the NAS recognizes that it is out of date and has announced a meeting to begin the planning for BEIR VIII. I’ll be there on November 17 and will report on what happens.
We’ve gone over this history before (here). Your summary of it is incorrect. As is your presumption of no documented negative health impacts from radiation exposures below rate of 2 mSv/day for a year or longer (730 mSv/y).
It’s hard to know where to take the discussion after such inaccurate statements (particularly on health impacts). We certainly can’t build anything independently objective or scientifically meaningful from them (if we throw in much of the relevant and available health and science literature in mix).
What are the documented negative health effects? Can you point to them for me, please?
You may have provided your thoughts before, but that does not mean that I accepted them above a peer reviewed article by someone who has conducted extensive research in the field, both historical and scientific.
It’s rather obvious Rod. I’ve said most studies. This respected summary article (cited 601 times) you can read on-line.
“Little question exists that intermediate and high doses of ionizing radiation, say >100 mSv, given acutely or during a prolonged
period, produce deleterious consequences in humans, including, but not exclusively, cancer” (p. 13761).
That is not what I asked for. I don’t want a “little question exists” statement. I’d like to see a study that identified or measured harm. What is the basis for the statement?
Once again, you are pointing to a paper written more than 10 years ago by people who have built their careers on the LNT. Their “review article” provides no data and rests solely on epidemiology papers that quote each other and automatically exclude any data that shows a negative relative risk and then draw a “best fit line” through data even if a J-curve that passes below zero is a better statistical fit.
Yes it is. As a review article, there are numerous references to specific research and findings that support the general conclusions of the paper (LNT and otherwise).
You asked for a reference to a study of documented negative health effects at a specified dose level. This article has plenty …
I asked for a study that measures negative effects, not a list of papers that assume negative effects and then prove that assumption with one-sided statistical analysis.
You seem confused how to read and understand such a review article? I’m not sure what can be done about this since it is pretty basic and fundamental to the topics we are discussing.
If you don’t see papers here that support the established conclusion of health impacts well within the range we are discussing … you don’t appear to be looking very carefully, or understanding the material in front of you.
We can’t discuss anything unless you are willing to acknowledge these studies exist. I think I’m starting to understand why you write about things that are clearly disproven and unsupported in most of the available scientific literature. You seem to be not aware that such findings exists (or deny their existence when they are put in front of you).
Maybe in soft sciences, review articles like the one to which you pointed are useful. In hard sciences, where answers really do exist, you would be able to simply pick one of the papers and point out how the researchers exposed mammals to a certain dose and were able to measure a certain effect with reasonably small error bars.
My understanding of the circumstances surrounding the imposition of the LNT model lead me to the conclusion that it was carefully selected because it purported effects that could not be measured. Low dose radiation could only result in scary numbers if you accepted the notions that DNA is stable, that human beings have no adaptive responses to insults, that defective mutations inevitably propagate and cause a small, but certain probability in a very large population, and — because the probability can be applied to a very large population — the potential number of affected people (over many generations) is large enough to be worth worrying about.
Once the LNT pushed by the geneticists had been accepted and promoted heavily through press releases, press conferences, friendly journalists, and popular scientists supported by the promoting foundation, it was a short step to make the assertion that cancer was caused by radiation. After all, one common theory at the time was that cancer was caused by genetic mutation. Though I am no expert, I am under the impression that is no longer a very common explanation for cancer initiation. It is, however, still a part of the regulatory assumption.
Just in case others are interested in some of the material that has helped me reach this conclusion, here is a link to a document written 40 years after the 1956 NAS BEAR genetics committee released its report. The author was a member of that committee and describes a little bit of the discussions that took place during its deliberations.
Quarreling Geneticists and a Diplomat
Note: I’ve had the experience of being a “diplomat” in a situation similar to the one in which Warren Weaver served. I was a “requirements officer” at OPNAV and was assigned to mediate a dispute between representatives of several of the commands that we resourced. It was easy for me to encourage cooperation; I held the “checkbook” for all of the people at the meeting.
Rod … there is an abundance of studies that show health risks in the dose range we are discussing. I am even confident saying MOST studies show this (and have provided you with a substantive and very well regarded review article at your request that points to the same). If you don’t want to acknowledge this, but have something else to say about LNT and what it means for radiation protection, that’s fine. But it doesn’t mean you have commented on anything of substance about this research, or shown any awareness that your statements are contradicted by MOST of the available research on this topic?
You seem perfectly willing to acknowledge that the hard sciences are capable of providing answers to these questions, you just wouldn’t know it from any of your statements (which are directly at odds and contradict most of the available research and fully documented objective findings on this topic).
Once again EL has no evidence or case study to point to. Just more generic fuzzy ambiance.
EL let us be more explicit. Come up with a single study, just one, that shows that dose rates below 2 mSv/day exposure fit a linear, no threshold model. Just one.
How do you figure that … the paper I cited is full of them. You’re claiming illiteracy as a defense of your position?
LNT deniers are in the same class as Holocaust deniers.
@Susanne E. Vandenbosch
Are you serious? Your comments are normally quite sane, but that comment aligns you with people like Bob Applebaum.
There is nothing remotely similar Holocaust denial involved in questioning a model that even proponents admit is unlikely to work as initially proposed in the low dose range. They strive to retain the model by calling it a “conservative” basis for regulation, or applying a wide ranging fudge factor known as the Dose and Dose Rate Effectiveness Factor (DDREF) that can be selected for a number somewhere between 2 and 10 (sometimes even higher) to adjust the “linear” slope to make observed data (with large error bars) fall back into the range of probability for the model.
People who have serious questions about the accuracy and utility of the model have not simply denied the existence of the LNT, but have done serious observational and experimental work to determine a more accurate representation of the health effects of low dose radiation. Some of us have also delved deeply into historical documents to determine how the model was chosen to replace the existing threshold dose response model and then how that selection was promoted and supported in order to make it the “consensus” upon which radiation protection regulations around the work are based.
Please check your premises and revise your accusation.
I will think about it.
S. E. Vandenbosch
Here is some news. President Obama has nominated Baran for a full term on the NRC. Senator Vitter is calling for a committee hearing on this nomination and has questioned the qualifications of Baran for this position.
Allison MacFarlane, Chairman of the Nuclear Regulatory Commission gave a speech on nuclear safety to the National Press Club today. She said that Congress needs to appropriate money to finish licensing Yucca Mountain and deal with challenges. Left unsaid was the fact that she has not requested funds for these activities.
Correction: President Obama has nominated Baran to complete the term of Allison MacFarlane.
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