RadCast has had the opportunity to speak with Dr. Ian Fairle about his studies. He is easily accessible and willing to discuss questions anyone might have. This article is one his most important works for us at RadCast implicating proximity to nuclear power plants resulting in childhood leukemias and worker risks for leukemia as you can see further down.
Click HERE to see an update and explanation from Aug 2014 by Dr. Fairle regarding the article posted below.
From Dr. Ian Fairle’s Blog: From March 2014
In March 2014, my article on increased rates of childhood leukemias near nuclear power plants (NPPs) was published in the Journal of Environmental Radioactivity (JENR). A previous post discussed the making of the article and its high readership: this post describes its content in layman’s terms.
Before we start, some background is necessary to grasp the new report’s significance. Many readers may be unaware that increased childhood leukemias near NPPs have been a contentious issue for several decades. For example, it was a huge issue in the UK in the 1980s and early 1990s leading to several TV programmes, Government Commissions, Government committees, a major international Conference, Government reports, at least two mammoth court cases and probably over a hundred scientific articles. It was refuelled in 1990 by the publication of the famous Gardner report (Gardner et al, 1990) which found a very large increase (7 fold) in child leukemias near the infamous Sellafield nuclear facility in Cumbria.
The issue seems to have subsided in the UK, but it is still hotly debated in most other European countries, especially Germany.
The core issue is that, world-wide, over 60 epidemiological studies have examined cancer incidences in children near nuclear power plants (NPPs): most (>70%) indicate leukemia increases. I can think of no other area of toxicology (eg asbestos, lead, smoking) with so many studies, and with such clear associations as those between NPPs and child leukemias. Yet many nuclear Governments and the nuclear industry refute these findings and continue to resist their implications. It’s similar to the situations with cigarette smoking in the 1960s and with man-made global warming nowadays.
In early 2009, the debate was partly rekindled by the renowned KiKK study (Kaatsch et al, 2008) commissioned by the German Government which found a 60% increase in total cancers and 120% increase in leukemias among children under 5 yrs old living within 5 km of all German NPPs. As a result of these surprising findings, governments in France, Switzerland and the UK hurriedly set up studies near their own NPPs. All found leukemia increases but because their numbers were small the increases lacked “statistical significance”. That is, you couldn’t be 95% sure the findings weren’t chance ones.
This does not mean there were no increases, and indeed if less strict statistical tests had been applied, the results would have been “statistically significant”. But most people are easily bamboozled by statistics including scientists who should know better, and the strict 95% level tests were eagerly grasped by the governments wishing to avoid unwelcome findings. Indeed, many tests nowadays in this area use a 90% level.
In such situations, what you need to do is combine datasets in a meta-study to get larger numbers and thus reach higher levels of statistical significance. The four governments refrained from doing this because they knew what the answer would be, viz, statistically significant increases near almost all NPPs in the 4 countries. So Korblein and Fairlie helped them out by doing it for them (Korblein and Fairlie, 2012), and sure enough there were statistically significant increases near all the NPPs. Here are their findings-
Studies of observed (O) and expected (E) leukemia cases within 5 km of NPPs
a derived from data in Spycher et al. (2011).
b acute leukemia cases
This table reveals a highly statistically significant 37% increase in childhood leukemias within 5 km of almost all NPPs in the UK, Germany, France and Switzerland. It’s perhaps not surprising that the latter 3 countries have announced nuclear phaseouts and withdrawals. It is only the UK government that remains in denial.
So the matter is now beyond question, ie there’s a very clear association between increased child leukemias and proximity to NPPs. The remaining question is its cause(s).
Most people worry about radioactive emissions and direct radiation from the NPPs, however any theory involving radiation has a major difficulty to overcome, and that is how to account for the large (~10,000 fold) discrepancy between official dose estimates from NPP emissions and the clearly-observed increased risks.
My explanation does involve radiation. It stems from KiKK’s prinicipal finding that the increased incidences of infant and child leukemias were closely associated with proximity to the NPP chimneys. It also stems from KiKK’s observation that the increased solid cancers were mostly “embryonal”, ie babies were born either with solid cancers or with pre-cancerous tissues which, after birth, developed into full-blown tumours: this actually happens with leukemia as well.
My explanation has five main elements. First, the cancer increases may be due to radiation exposures from NPP emissions to air. Second, large annual spikes in NPP emissions may result in increased dose rates to populations within 5 km of NPPs. Third, the observed cancers may arise in utero in pregnant women. Fourth, both the doses and their risks to embryos and to fetuses may be greater than current estimates. And fifth, pre-natal blood-forming cells in bone marrow may be unusually radiosensitive. Together these five factors offer a possible explanation for the discrepancy between estimated radiation doses from NPP releases and the risks observed by the KIKK study. These factors are discussed in considerable detail in the full article.
My article in fact shows that the current discrepancy can be explained. The leukemia increases observed by KiKK and by many other studies may arise in utero as a result of embryonal/fetal exposures to incorporated radionuclides from NPP radioactive emissions. Very large emission spikes from NPPs might produce a pre-leukemic clone, and after birth a second radiation hit might transform a few of these clones into full-blown leukemia cells. The affected babies are born pre-leukemic (which is invisible) and the full leukemias are only diagnosed within the first few years after birth.
To date, no letters to the editor have been received pointing out errors or omissions in this article.
Bithell JF, M F G Murphy, C A Stiller, E Toumpakari, T Vincent and R Wakeford. (2013) Leukaemia in young children in the vicinity of British nuclear power plants: a case–control study. Br J Cancer. advance online publication, September 12, 2013; doi:10.1038/bjc.2013.560.
Bunch KJ, T J Vincent1, R J Black, M S Pearce, R J Q McNally, P A McKinney, L Parker, A W Craft and M F G Murphy (2014) Updated investigations of cancer excesses in individuals born or resident in the vicinity of Sellafield and Dounreay. British Journal of Cancer (2014), 1–10 | doi: 10.1038/bjc.2014.357
Fairlie I (2013) A hypothesis to explain childhood cancers near nuclear power plants. Journal of Environmental Radioactivity 133 (2014) 10e17
Gardner MJ, Snee MP; Hall AJ; Powell CA; Downes S; Terrell JD (1990) Results of case-control study of leukaemia and lymphoma among young people near Sellafield nuclear plant in West Cumbria. BMJ. 1990;300:423–429.
Kaatsch P, Spix C, Schulze-Rath R, Schmiedel S, Blettner M. (2008) Leukaemia in young children living in the vicinity of German nuclear power plants. Int J Cancer; 122: 721-726.
Körblein A and Fairlie I (2012) French Geocap study confirms increased leukemia risks in young children near nuclear power plants. Int J Cancer 131: 2970–2971.
Spycher BD, Feller M, Zwahlen M, Röösli M, von der Weid NX, Hengartner H, Egger M, Kuehni CE. Childhood cancer and nuclear power plants in Switzerland: A census based cohort study. International Journal of Epidemiology (2011) doi:10.1093/ije/DYR115.http://ije.oxfordjournals.org/content/early/2011/07/11/ije.dyr115.full.pdf+html
In 2013, I discussed several epidemiological studies providing good evidence of radiogenic risks at very low exposure levels.
A powerful new study (1) has been published in Lancet Haematology which adds to this evidence. However the study’s findings are more important than the previous studies, for several reasons.
First, it provides “strong evidence”, as stated by the authors, of a “dose-response relationship between cumulative, external, chronic, low-dose, exposures to radiation and leukaemia”.
Second, it finds radiogenic risks of leukemia among nuclear workers to be more than double the risk found in a previous similar study in 2005. The excess relative risk of leukaemia mortality (excluding workers exposed to neutrons) was 4.19 per Gy. In 2005, a similar study (2) among nuclear workers (also excluding those exposed to neutrons) in 15 countries by several of the same authors found an ERR of 1·93 per Sv. In other words, the new study’s risk estimates are 117% higher than the older study. The clincher is that the new study’s estimated risks are much more precise than before.
Third, it confirms risks even at very low doses (mean = 1·1 mGy per year). Unlike the Japanese bomb survivors’ study, it observes risks at low dose rates rather than extrapolating them from high levels.
Fourth, it finds risks do not depend on dose rate thus contradicting the ICRP’s use of a Dose Rate Effectiveness Factor (DREF) which acts to reduce (by half) the ICRP’s published radiation risks.
Fifth, it finds radiogenic leukemia risks decline linearly with dose, contradicting earlier studies suggesting a lower, linear-quadratic relationship for leukemia. It strengthens the Linear No Threshold (LNT) model of radiogenic risks, as it now applies to leukemias as well as solid cancers.
Sixth, the study finds no evidence of a threshold below which no effects are seen (apart from zero dose).
Seventh, the study uses 90% confidence intervals and one -sided p-values. In the past, 95% intervals and two-sided p-values were often incorrectly used which had made it harder to establish statistical significance.
Explanation for change
In an earlier version of this blog posted on June 29 2015, I’d written that the increase between the 2005 study and the present study was 50%, ie up from 1.93 to 2.96 per Gy. This was because the study’s Discussion section specifically compared these two studies and their risks, stating the older study’s leukemia risk was smaller and less precise.
However a detailed examination of the report reveals the following sentence in the para immediately before the Discussion section. “We assessed the effect of excluding people who had recorded neutron exposures; we showed a positive association for leukaemia … (ERR per Gy 4·19, 90% CI 1·42–7·80, 453 deaths)…”. To make sure readers get the point, the risk is greater when neutron exposed workers are excluded.
This is important because the 2005 study excluded workers exposed to neutrons. Therefore the correct comparison is between the risks for non-neutron workers, that is between 4.19 and 1.93 per Gy – an increase of 117%, rather than 50%.
I’ve written to the report’s authors about this but have not received any replies yet, perhaps due to summer vacations. I shall keep readers up-to-date on any progress.
The study’s credentials are pretty impeccable. It’s a huge study of over 300,000 nuclear workers adding up to over 8 million person years, thus ensuring its findings are statistically significant, ie with very low probability of occurring by chance. Also, it’s an international study by 13 respected scientists from national health institutes in the US, UK, and France, as follows.
- Centers for Disease Control and Prevention, US
- National Institute for Occupational Safety and Health, US
- Department of Health and Human Services, US
- University of North Carolina, US
- Drexel University School of Public Health, US
- Public Health England, UK
- Institut de Radioprotection et de Sûreté Nucléaire, France
- Center for Research in Environmental Epidemiology, Spain
- UN International Agency for Research on Cancer, France
Funding was provided by many institutions, including US Centers for Disease Control and Prevention, US National Institute for Occupational Safety and Health, US Department of Energy, US Department of Health and Human Services, Japanese Ministry of Health Labour and Welfare, French Institut de Radioprotection et de Sûreté Nucléaire, and the UK’s Public Health England.
This study powerfully contradicts the views of ill-informed and inexperienced journalists (including the UK writer, George Monbiot) and self-styled scientists who argue that radiation risks are over-estimated and even that radiation is somehow good for you. Hormetic effects are neither found nor discussed in this study: such irrelevant effects are regarded by real scientists as beneath their consideration. The impressive list of contributing scientists and their national institutions here should serve to make radiation risk deniers reconsider their views. This is particularly the case for US risk deniers, in view of the many US agencies and US scientists backing the study.
The study pointedly comments that “At present, radiation protection systems are based on a model derived from acute exposures, and assumes that the risk of leukaemia per unit dose progressively diminishes at lower doses and dose rates.” The study shows this assumption is incorrect. The authors therefore join with WHO and UNSCEAR scientists in their views that DREFs should not be used. The question remains whether the ICRP will accept this powerful evidence and scrap their adherence to using DREFs. I advise readers not to hold their breaths.
As regards the implications of their study, the authors interestingly choose to comment – not on exposures from the nuclear industry – but from medical exposures. They state “Occupational and environmental sources of radiation exposure are important; however, the largest contributor to this trend is medical radiation exposure. In 1982, the average yearly dose of ionising radiation from medical exposures was about 0·5 mGy per person in the USA; by 2006, it had increased to 3·0 mGy.2 A similar pattern exists in other high-income countries: use of diagnostic procedures involving radiation in the UK more than doubled over that period3 and more than tripled in Australia.4 Because ionising radiation is a carcinogen,5 its use in medical practice must be balanced against the risks associated with patient exposure.6
This is all correct and worrying, especially the revelation that medical radiation doses increased 6-fold in the US and doubled in the UK between 1982 and 2006. The authors add “This finding shows the importance of adherence to the basic principles of radiation protection—to optimise protection to reduce exposures as much as reasonably achievable and—in the case of patient exposure—to justify that the exposure does more good than harm.” The same, of course, applies to exposures from the nuclear industry – the actual subject of their research.
(1) Leuraud, Klervi et al (2015) Ionising radiation and risk of death from leukaemia and lymphoma in radiation-monitored workers (INWORKS): an international cohort study. The Lancet Haematology Published Online: 21 June 2015.
(2) Cardis E et al (2005) Risk of cancer after low doses of ionising radiation: retrospective cohort study in 15 countries. BMJ 2005;331:77.
I thank Dr Alfred Körblein and Professor Keith Baverstock for their insights in preparing this article. Any errors are my responsibility.