FacebookTwitterGoogle+RedditEmail

Radiation and Cancer: Risks of Leukemia in Nuclear Workers More Than Double Previous Estimate

In 2013, I discussed several epidemiological studies providing good evidence of radiogenic risks at very low exposure levels.

A powerful new study has been published in Lancet Haematology [1] 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 29th June 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. I shall keep readers up-to-date on any progress.

Study’s credentials

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.

My conclusions

This study powerfully contradicts the views of ill-informed and inexperienced journalists (including the UK writer George Monbiot) [3] 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.

“A similar pattern exists in other high-income countries: use of diagnostic procedures involving radiation in the UK more than doubled over that period and more than tripled in Australia. Because ionising radiation is a carcinogen, its use in medical practice must be balanced against the risks associated with patient exposure.

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.

More articles by:

Dr Ian Fairlie is an independent consultant on radioactivity in the environment. He has a degree in radiation biology from Bart’s Hospital in London and his doctoral studies at Imperial College in London and Princeton University in the US concerned the radiological hazards of nuclear fuel reprocessing. Ian was formerly a DEFRA civil servant on radiation risks from nuclear power stations. From 2000 to 2004, he was head of the Secretariat to the UK Government’s CERRIE Committee on internal radiation risks. Since retiring from Government service, he has acted as consultant to the European Parliament, local and regional governments, environmental NGOs, and private individuals.

Weekend Edition
September 21, 2018
Friday - Sunday
Alexandra Isfahani-Hammond
Hurricane Florence and 9.7 Million Pigs
Andrew Levine
Israel’s Anti-Semitism Smear Campaign
Paul Street
Laquan McDonald is Being Tried for His Own Racist Murder
Brad Evans
What Does It Mean to Celebrate International Peace Day?
Nick Pemberton
With or Without Kavanaugh, The United States Is Anti-Choice
Jim Kavanagh
“Taxpayer Money” Threatens Medicare-for-All (And Every Other Social Program)
Jonathan Cook
Palestine: The Testbed for Trump’s Plan to Tear up the Rules-Based International Order
Jeffrey St. Clair
Roaming Charges: the Chickenhawks Have Finally Come Back Home to Roost!
David Rosen
As the Capitalist World Turns: From Empire to Imperialism to Globalization?
Jonah Raskin
Green Capitalism Rears Its Head at Global Climate Action Summit
James Munson
On Climate, the Centrists are the Deplorables
Robert Hunziker
Is Paris 2015 Already Underwater?
Arshad Khan
Will Their Ever be Justice for Rohingya Muslims?
Jill Richardson
Why Women Don’t Report Sexual Assault
Dave Clennon
A Victory for Historical Accuracy and the Peace Movement: Not One Emmy for Ken Burns and “The Vietnam War”
W. T. Whitney
US Harasses Cuba Amid Mysterious Circumstances
Nathan Kalman-Lamb
Things That Make Sports Fans Uncomfortable
George Capaccio
Iran: “Snapping Back” Sanctions and the Threat of War
Kenneth Surin
Brexit is Coming, But Which Will It Be?
Louis Proyect
Moore’s “Fahrenheit 11/9”: Entertaining Film, Crappy Politics
Ramzy Baroud
Why Israel Demolishes: Khan Al-Ahmar as Representation of Greater Genocide
Ben Dangl
The Zapatistas’ Dignified Rage: Revolutionary Theories and Anticapitalist Dreams of Subcommandante Marcos
Ron Jacobs
Faith, Madness, or Death
Bill Glahn
Crime Comes Knocking
Terry Heaton
Pat Robertson’s Hurricane “Miracle”
Dave Lindorff
In Montgomery County PA, It’s Often a Jury of White People
Louis Yako
From Citizens to Customers: the Corporate Customer Service Culture in America 
William Boardman
The Shame of Dianne Feinstein, the Courage of Christine Blasey Ford 
Ernie Niemi
Logging and Climate Change: Oregon is Appalachia and Timber is Our Coal
Jessicah Pierre
Nike Says “Believe in Something,” But Can It Sacrifice Something, Too?
Paul Fitzgerald - Elizabeth Gould
Weaponized Dreams? The Curious Case of Robert Moss
Olivia Alperstein
An Environmental 9/11: the EPA’s Gutting of Methane Regulations
Ted Rall
Why Christine Ford vs. Brett Kavanaugh is a Train Wreck You Can’t Look Away From
Lauren Regan
The Day the Valves Turned: Defending the Pipeline Protesters
Ralph Nader
Questions, Questions Where are the Answers?
Binoy Kampmark
Deplatforming Germaine Greer
Raouf Halaby
It Should Not Be A He Said She Said Verdict
Robert Koehler
The Accusation That Wouldn’t Go Away
Jim Hightower
Amazon is Making Workers Tweet About How Great It is to Work There
Robby Sherwin
Rabbi, Rabbi, Where For Art Thou Rabbi?
Vern Loomis
Has Something Evil This Way Come?
Steve Baggarly
Disarm Trident Walk Ends in Georgia
Graham Peebles
Priorities of the Time: Peace
Michael Doliner
The Department of Demonization
David Yearsley
Bollocks to Brexit: the Plumber Sings
FacebookTwitterGoogle+RedditEmail