Radiation Effects Research Foundation (RERF) is the successor organization of the Atomic Bomb Casualty Commission (ABCC) to conduct investigations of the late effects of radiation among the atomic-bomb survivors in Hiroshima and Nagasaki.
In its 14th report on mortality in the Life Span Study (LSS) cohort of atomic bomb survivors published in March this year in the "Radiation Research" magazine, the official journal of the US Radiation Research Society, the researchers at RERF say there was no "threshold":
Importantly, for solid cancers the additive radiation risk (i.e., excess cancer cases per 104 person-years per Gy) continues to increase throughout life with a linear dose–response relationship.
The estimated lowest dose range with a significant ERR [excess relative risk] for all solid cancer was 0 to 0.20 Gy, and a formal dose-threshold analysis indicated no threshold; i.e., zero dose was the best estimate of the threshold.
According to the blogger who posted the link to the paper says he/she called the Ministry of Health and Welfare on May 1 and asked: "Ministry of Health and Ministry of Foreign Affairs oversee the RERF. I understand from this report that it has now been epidemiologically proven that even a low-dose radiation exposure resulted in negative health effect such as dose-dependent increase in cancer. This is contrary to the position of the Japanese government which is based on the IRCP assertion that there is no epidemiological proof that there is a health risk in low-dose radiation exposure but the radiation protection standards are set assuming there is such a risk. Is there any press release planned by the Ministry of Health? Is my understanding correct?" The answer from the official in charge at the Ministry was, according to him/her, "Your understanding is correct. The Ministry doesn't have a plan for any press release, because the RERF has already done so."
There is hardly any coverage of this paper by the mainstream media in Japan.
While the RERF continues to study (and not treat) the effect of atomic bombs on human health, there is a worthy successor in Fukushima Medical University, headed by Dr. Shunichi Yamashita. He has been mostly quite successful in convincing the residents in Fukushima Prefecture to continue to live in Fukushima. That gives him close to 2 million subjects to study. By the way, Dr. Yamashita's stance is that "unless you are exposed to radiation at 100 millisieverts or more in a single episode, there is no increase in cancer risks". Well the RERF study seems to finally disprove that.
The abstract part of the paper by Ozasa, K., Shimizu, Y., Suyama, A., Kasagi, F., Soda, M., Grant, E. J., Sakata, R., Sugiyama, H. and Kodama, K. "Studies of the Mortality of Atomic Bomb Survivors, Report 14, 1950–2003: An Overview of Cancer and Noncancer Diseases. Radiat. Res. 177, 229–243 (2012)":
This is the 14th report in a series of periodic general reports on mortality in the Life Span Study (LSS) cohort of atomic bomb survivors followed by the Radiation Effects Research Foundation to investigate the late health effects of the radiation from the atomic bombs. During the period 1950–2003, 58% of the 86,611 LSS cohort members with DS02 dose estimates have died. The 6 years of additional follow-up since the previous report provide substantially more information at longer periods after radiation exposure (17% more cancer deaths), especially among those under age 10 at exposure (58% more deaths). Poisson regression methods were used to investigate the magnitude of the radiation-associated risks, the shape of the dose response, and effect modification by gender, age at exposure, and attained age. The risk of all causes of death was positively associated with radiation dose. Importantly, for solid cancers the additive radiation risk (i.e., excess cancer cases per 104 person-years per Gy) continues to increase throughout life with a linear dose–response relationship. The sex-averaged excess relative risk per Gy was 0.42 [95% confidence interval (CI): 0.32, 0.53] for all solid cancer at age 70 years after exposure at age 30 based on a linear model. The risk increased by about 29% per decade decrease in age at exposure (95% CI: 17%, 41%). The estimated lowest dose range with a significant ERR for all solid cancer was 0 to 0.20 Gy, and a formal dose-threshold analysis indicated no threshold; i.e., zero dose was the best estimate of the threshold. The risk of cancer mortality increased significantly for most major sites, including stomach, lung, liver, colon, breast, gallbladder, esophagus, bladder and ovary, whereas rectum, pancreas, uterus, prostate and kidney parenchyma did not have significantly increased risks. An increased risk of non-neoplastic diseases including the circulatory, respiratory and digestive systems was observed, but whether these are causal relationships requires further investigation. There was no evidence of a radiation effect for infectious or external causes of death.
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16 comments:
Isn't this just another confirmation of the Linear Non-Threshold model? It's based on extrapolations from higher doses (over 200 mSv), but it has been accepted by every radiological protection agency except the french academy for a couple of decades.
But I don't think the gov is saying that there won't be any increase in cancer, but rather that the increases in cancer risk for doses under 20 mSv do not require evacuation (check the meetings of the workshop for low radiation risks which Hosono organized, specially the last one.)
The problem is that cancer is not the only risk. Immune and cardiovascular diseases increased also after Chernobyl, but aren't recognized as effects of radioactive contamination.
Yes, except it seems it is now epidemiologically proven, instead of hypothesis.
@ Anon 9:37pm said: "...but it has been accepted by every radiological protection agency"
I am American. From the time of the Fukushima disaster to the present, I have debated American nuclear engineers and others in the nuke industry who insist that the research which proves Linear Non-Threshold does not prove that there is no threshhold. In fact, these 'experts' insist that large, well documented research efforts like the National Academy of Sciences BEIR VII report proves the opposite. I provided an excerpt from the BEIR VII which clear said "Despite what many working in the nuclear industry would like to believe, there there is no safe threshold. The person I was responding to, a nuclear engineer, replied in all caps "THE REPORT DOES NOT SAY THAT!" The nuclear industry simply denies the research and accuses those who point to it as liars and 'fear mongers' (in the US). They also insist that concerns about radiation are sheer wild speculation - as if people suffering in the Ukraine today for the Chernobyl disaster years ago do not exist, are not ill, and that nothing has been documented. I believe that the nuclear industry has a 'zero tolerance' for admitting to even the smallest detail that is proven by research because they fear even a small crack in their defenses will be the end of their careers. Plenty of medical proof exists but he nuclear industry conducts business as if no proof exists and as if those who are concerned are mentally ill. This is why they created the myth that 'fear of radiation is more damaging than exposure to radiation'. They claim there is proof of this in the affected regions of Chernobyl. Interesting that the nuke industry has two different standards of proof: they reject well researched medical studies as if they are signs of mental illness but they claim their deepest wishes are actual proof that radiation is safe.
Anon, I have seen the same thing all over the internet since last year. But I think even the nuke industry in the US accepts the LNT model as the basis. I mean, they use 2 rem / 20 mSv per year as the accepted dose for nuclear workers. If they really rejected the LNT, they would be using 100-200 mSv like in the 50s.
Sooo... LNT is confirmed once again (for the how manyeth time>), ALARA model stands, Japanese children hold track meets in radioactive dust.
What is wrong with this picture?
Nothing's wrong. Dr. Yamashita and his younger associates will have their study subjects for years to come.
Anonymous at 10:18 pm said:
"Plenty of medical proof exists but [t]he nuclear industry conducts business as if no proof exists and as if those who are concerned are mentally ill."
I would think, they really mean and believe it. I am not anything like a doctor or so, but over time came to a strong conviction, that that industry itself has a very high density of mentally ill people. These people quite naturally mix up reality and their phantasies, have delusions about their own grandeur and perfectness, lying and manipulating to achieve their ends is quite normal thinking for them, this includes declaring the sane people to be mentally ill.
Like the tobacco and asbestos industries before them the nuclear industry is well aware of the dangers. Their continued denial is simply a callous strategy to maximise returns on investments for as long as possible.
If this were not the case then why the ban on atmospheric nuclear tests way back in the 70's? Why was a small increase in background radiation enough to get all govts to go to the trouble of underground tests, and miss out on watching a really good explosion? After all they were no-where near 20mSv year yet. Probably because by then they knew enough, and didnt want to carry the future health/economic/political burden of even tiny increases.
The difference is that tobacco etc were not critical to the defense industry, and hence the govt.
So in nuclear we have an industry spreading pr crap to protect profits, and a govt who are quietly letting that happen, for the military advantage.
Since the govt is already underwriting the downside risks of nuclear (loans, insurance, cleanup, health, etc) and those wont go away even if nuclear stops tomorrow, then where is the political motivation for making a difficult decision to stop nuclear?
And what about the political dangers of even suggesting it, the backstabbing,the loss of campaign funds, etc.
One mother of a problem...
Our gracious host gives a link to the report: http://www.rrjournal.org/doi/pdf/10.1667/RR2629.1
Look at Fig. 5 on page 10. This charts the excess relative risk per Gray (ERR/Gy) for all solid cancer for selected dose ranges. The confidence intervals (CI) > 0.5 Gy (500mGy) are fairly tight. But below that, the confidence intervals appear to grow exponentially and start to include 0 at about 0.2 Gy (200mGy), which is still a fairly high dose. Normally, when confidence intervals include zero, that means that the results are statistically indistinguishable from 0. That would mean, in this case, that you CANNOT say, with a 95% confidence, that the ERR is greater than 0 below 0.2 Gy. That does NOT mean that you can conclude that 0.2 Gy is the threshold, as that conclusion is also not supported. The correct interpretation, IMHO, is that you have insufficient information to say that there is an increased risk of cancer at exposures of 0.2 Gy or below WITH 95% CONFIDENCE. The data is simply not good enough.
In short, it would seem that the authors are overstating their results. Please don't flame me, as I am not saying that there is no risk of cancer at low dosages. I just think that both sides are overstating the evidence. On one side, ALL excess cancers are being attributed to radiation, unless otherwise explained and, on the other, ANY reduction in cancer rate is attributed to the supposedly beneficial effects of radiation (i.e. hormesis). It is the same statistical assumption, only in mirror image.
The large sample size is not necessarily a benefit. One issue is that a large sample size may introduce more confounding variables than it is possible to control for. For example, smoking tobacco plus asbestos exposure has an almost 100% risk of lung cancer, given enough time (sometimes 40 years). Analyzing ERR for tobacco without controlling for asbestos exposure would skew the statistics. The same would be true when analyzing asbestos without controlling for tobacco exposure.
In short, the mean values support the LNT hypothesis, but there is too much variability in the data at low dosages (hence the wide CIs) to justify concluding that the LNT hypothesis is supported with a confidence of 95% at dosages below 0.2 Gy.
" there is too much variability in the data at low dosages (hence the wide CIs) to justify concluding that the LNT hypothesis is supported with a confidence of 95% at dosages below 0.2 Gy"
Not to worry. There is a huge cohort of new test cases coming our way, as the kids in Fukushima prefecture have been fitted with dosimeters.
The data will be clear as day in two or three decades' time. Too late for all involved, of course, but what the hey? Science is science, amirite?
The doses in Fukushima, at least the ones registered by the glass badges, are too low. 95% of them are below 2-3 mSv year. Even with 200,000 kids, they won't have enough data. I think for those doses you need 100 million subjects, or something similar (because of what anon said on his post about statistical significance.)
Unless kids start getting thyroid cancer two or three years from now people will forget the whole thing, and several decades from now someone will prove there was increased leukemia or heart problems, and some families would get some money from the government after long legal processes. Maybe some of the people responsible are still alive by then, but I doubt anyone would be charged.
ALL OF THIS NUCLEAR MADNESS IS DRIVEN BY GREED, FEAR & LACK OF COMPASSION FOR LIFE. A NUCLEAR CEO MAKES A MILLION A YEAR, PEOPLE IN NUCLEAR DEFEND IT LIKE IT IS NOTHING TO WORRY ABOUT AND COUNTRIES AROUND THE WORLD ARE TRYING TO DUPLICATE OUR STUPIDITY IN DEVELOPING IT'S POWER. JAPAN PROVED HOW TOTALLY STUPID IT IS !!! A WORLD FULL OF MUTANTS & ILL CHILDREN IS NOT A PRETTY THOUGHT, NOR AN INABILITY TO GROW HEALTHY FOOD, DRINK CLEAN WATER & BREATHE FRESH AIR. EVENTUALLY, HUMANITY WILL DISAPPEAR FOR THE LACK OF SANITY & GRACE. AN THE EARTH WILL RENEW IT SELF, OR SO I HOPE.
>WORLD FULL OF MUTANTS & ILL CHILDREN IS NOT A PRETTY THOUGHT, NOR AN INABILITY TO GROW HEALTHY FOOD, DRINK CLEAN WATER & BREATHE FRESH AIR
I really think a lot of people was living in Disney world before Fukushima and now they are living in some kind of horror movie.
>> The doses in Fukushima, at least the ones registered by the glass badges, are too low.
No. The glass badges only register external exposure. They do not register internal contamination, which is the biggest long term problem, and which breeds a ot of cancer.
F4ERU
Quite right, internal contamination is the big worry.The radioactive particle can be infinitesimally small, but if lodged within, is constantly bombarding nearby tissue. The pro-nuke argument seesm to be that LNT model is not accurate with radiation doses below 100msv (I had that argument thrown at me just yesterday). This report is yet another in the last 10 years that seesm to show that radition doses even below 20msv cause genetic damage. Just found that the Bulletin of Atomic Scientists (May/June issue)has 6 article report that also points to this conclusion. Its free to peruse or download.
Thanks for this site. You are doing a very important job. I'm also in Japan and it was very helpful during the crisis last year when the media in Japan were lying through their teeth.
Then why doesn't the research in areas of high background radiation corroborate LNT?
Areas such as Kerala India, Ramsar Iran have very high background radiation levels and yet the research can NOT support the LNT.
The cobalt-60 incident in Taiwan has been thoroughly studied and shown that people living in the higher active housing were in fact healthier than the norm.
This very confusing.
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