Is a Little Radiation Good For You? Trump Admin Steps Into Shaky Science

By Nathaniel Scharping | October 5, 2018 4:40 pm
geiger counter radiation

A technician scans for radiation with a Geiger counter. (Credit: PRESSLAB/Shutterstock)

For decades, studies have shown that even low doses of radiation are harmful to humans.

This week, the Associated Press reported that the Trump administration may be reconsidering that. The Environmental Protection Agency seemed to be looking at raising the levels of radiation considered dangerous to humans based on a controversial theory rejected by mainstream scientists. The theory suggests that a little radiation might actually be good for our bodies. In April, an EPA press release announced the proposal and included supporting comments from a vocal proponent of the hypothesis, known as hormesis. It prompted critical opinion pieces and sparked worry among radiation safety advocates.

Those comments back in April were made by Edward Calabrese, a toxicologist at the University of Massachusetts, Amherst, who also testified before Congress on the issue this week. And in the initial release, Calabrese hailed the EPA’s decision to move away from the radiation dose model widely accepted by the scientific mainstream. But by Friday, the EPA backed away from Calabrese’s stance in comments to Discover.

The debate cuts to the heart of the debate over the effects of low doses of radiation and reveals how difficult it is to craft clear guidelines in an area where scientific evidence is not clear cut.

Radiation Debate

When radiation damages our DNA, the body steps in to make repairs. Hormesis suggests that hitting the body with a little more radiation should kick our defensive mechanisms into overdrive. According to proponents of the theory, this results in the production of anti-oxidants and anti-inflammatory compounds that reduce our risk for cancer and heart disease, among other things. That’s why hormesis backers want the EPA to raise the level of acceptable radiation, pointing out that it would also save millions in safety costs.

It sounds convincing, and proponents have dozens of studies to point to that they say back up their claims. But, there’s never been a large-scale human study of hormesis. And while studies of low-dose radiation are very hard to do, so far, most suggest that radiation is indeed bad for us, at any dose.

“Large, epidemiological studies provide substantial scientific evidence that even low doses of radiation exposure increase cancer risk,” says Diana Miglioretti, a professor in biostatistics at the University of California, Davis in an email. “Risks associated with low-doses of radiation are small; however, if large populations are exposed, the evidence suggests it will lead to measurable numbers of radiation-induced cancers.” 

Long-term studies of Hiroshima and Nagasaki bombing survivors show higher cancer risks. Marshall Islanders exposed to radiation from atomic bomb tests suffered a higher risk of thyroid disease. And patients who get CT scans, which deliver a dose of radiation equal to thousands of X-rays, saw cancer risks go up afterward. Researchers also found that radiation from childhood CT scans can triple the risk of leukemia and, at higher doses, triple the risk of brain cancers as well. Another found that low-dose radiation increased the risk of breast cancer among some some women.

And large-scale reviews of the evidence for hormesis find that it is decidedly lacking. Two studies, one in 2006 by the National Research Council, and another in 2018 by the National Council and Radiation Protection and Measurements looking at 29 studies of radiation exposure find no evidence for hormesis, and reiterate that the evidence points toward radiation being bad for us even at low doses.

Scientific Uncertainty

It’s difficult to study low doses of radiation, though, and that’s where much of the controversy comes from. At doses below a few hundred millisieverts (mSv), a radiation unit that accounts for its effects on the body, it becomes extraordinarily hard to separate out the effects of radiation from other things like lifestyle or genetics. Research on the effects of these small radiation doses often use data sets involving thousands of people to compensate for the minimal effect sizes, but even then it’s often not enough to be certain what’s happening. 

“Data collected at low doses (defined by the scientific community [as] exposures less than 100 mSv) suffers from a ‘signal to noise’ problem which limits our ability to conclusively state effects one way or another,” says Kathryn Higley, head of the school of nuclear science and engineering at Oregon State University in an email.

A single CT scan delivers anywhere from 1 to 15 mSv, but some patients need many scans during the course of their treatment, increasing the total dose. Workers cleaning up after the Fukushima meltdown received radiation doses above 100 mSv in some cases. And current U.S. standards limit radiation workers to no more than 50 mSv of exposure per year.

Many studies indicate that there are dangers at that level, but it’s often an assumption. Those studies base their suppositions on what’s called the linear no-threshold model, which extrapolates more reliable data from studies of higher doses of radiation to lower doses. Though it may be an educated guess, for decades large-scale studies have indicated this is true.

Muddying the Waters

But hormesis researchers say that those studies don’t add up. Mohan Doss, a researcher at the Fox Chase Cancer Center, believes that studies of CT scan patients are biased toward populations that might be predisposed to cancer. Similarly, Doss has a different interpretation of studies looking at Hiroshima and Nagasaki survivors. For example, he says that data from a 2012 study of bomb survivors actually does show evidence for hormesis, though the study’s authors came to a different conclusion. They found that cancer rates increased after the bombings even at low doses of radiation. This is in line with what most studies of bomb survivors have found, though Doss thinks its partly because cancer can sometimes by overdiagnosed in study populations.

Doss says that radiation levels of up to 300 or 400 mSv would likely be safe, and he supports increasing the maximum allowed annual dose in the U.S.

“The current limits for the public are insane,” he says. “Everyone is going to be safe at 100 mSv a year.”

Doing so would not only save money and potentially reduce the stress of evacuations in the case of nuclear emergencies, he says, but also make it easier to conduct studies involving low doses of radiation.

Doss is convinced that studies of low dose radiation do not provide evidence of harms. He points to several studies that indicate the opposite. For example, back in 1957, some 10,000 residents were evacuated from villages near the Mayak Nuclear Weapons Facility in Russia after a nuclear contamination incident. When scientists studied those same residents in 1994, they actually found a dip in cancer rates among people exposed to low levels of radiation.

It lines up with what researchers would expect if hormesis was true, he says, though the study authors do note that more refinement of their methods would be necessary to prove the absence of radiation effects.

Other research into the effects of radiation exposure at Mayak has found evidence of an increase in cancer rates following the event, though Doss disagrees with the findings of that study.

The EPA in recent days appeared to back away from the suggestion that it supported hormesis. The agency released a statement in response to the AP story affirming that it intends to continue using the linear no-threshold model when constructing radiation guidelines, something that contradicts Calabrese’s comments in the April press release.

“The proposed regulation doesn’t talk about radiation or any particular chemicals. EPA’s policy is to continue to use the linear-no-threshold model for population-level radiation protection purposes which would not – under the proposed regulation that has not been finalized – trigger any change in that policy,” said an EPA spokesman in response to a request for comment.

Playing It Safe

But radiologist Rebecca Smith-Bindman says the vast bulk of the evidence suggests even small amounts of radiation are harmful. We shouldn’t base our policies on an unproven theory, she adds. 

“There is extensive evidence that ionizing radiation will cause cancer,” says Smith-Bindman, a professor of radiology at the University of California, San Francisco in an email exchange. “These data come from a range of different sources, including epidemiological data (such as studies of patients who have received diagnostic and therapeutic radiation and from environmental exposures and accidents), from animal studies and from basic science studies. While it is more difficult to precisely quantify the exposures — which will vary by many factors, such as age at exposure, and source of radiation, etc. — there is no uncertainty among the scientific community that radiation will cause cancer.”

She says that pointing to issues with the linear no-threshold model misses the point. Though it may not be totally accurate at very low doses, she says it’s unfair to use that uncertainty to cast doubt on data about radiation where there’s solid evidence.

It’s still not clear, for example, how normal background radiation affects humans. That dose averages 3.1 mSv a year in the U.S., though it can vary considerably depending on where you live. Workers cleaning up after the Fukushima power plant spill were exposed to levels far beyond that: Over 150 people received doses in excess of 100 mSv, and six were exposed to more than 250 mSv. That’s two and five times, respectively, the current maximum dose recommended by the U.S. for radiation workers, though still within the range of acceptable short-term doses for emergency workers prescribed by several countries. It’s estimated that the 240,000 workers who helped to clean up the Chernobyl spill were likely exposed to radiation doses about 100 mSv, as well.

When it comes to actual health effects, though, the data is mixed. A WHO report found that risks of cancer from exposure at Fukushima were negligible. Yet cancers often don’t appear until years later, making it difficult to estimate the risks right now. After Chernobyl, workers cleaning up the spill and those from the area saw rates of thyroid cancer spike in the years afterward, though Doss also disagrees with how that data is interpreted. CT scan studies also fall in this range, and multiple groups of researchers have published data showing that the scans increase cancer risk.

Because data from studies isn’t totally conclusive, there’s some disagreement in the field over what constitutes an acceptable level of radiation. Some scientists do think the maximum acceptable doses could be higher.

“In terms of public health, even if we raise the standards to where they were back in the 1960s, we’re not likely to observe an adverse impact with the current scientific tools available to us,” Higley says. “There are populations around the world exposed to natural radiation at levels up to 100 mSv per year, and we haven’t seen measurable health effects.”

Those populations are small, though, so the uncertainties in that data are large, she adds.

Miglioretti disagrees: “Based on the large body of evidence to date, I believe that revising the regulations to increase allowable radiation exposure limits will lead to an increase in the number of radiation-induced cancers in this country.”

That’s in line with what multiple experts Discover contacted believe — that radiation can harm even at low doses and raising limits would endanger the public, though the increase in risk would likely be small.

It’s not clear at the moment whether the EPA proposal to raise limits will pass, though it does follow in the footsteps of other Trump administration proposals to weaken safety standards. At the moment, it’s unclear what the effects on the public if the EPA raises radiation limits.

“Perhaps it might make nuclear power plants less expensive to build. It might lower the cost of cleanup of radioactively polluted sites,” says David Brenner, director of the Center for Radiological Research at Columbia University in an email. “But [it] begs the question of whether cleanup to a less rigorous standard is desirable.”

 

[Update 10/8/2018: The article has been updated to remove the suggestion that Doss believes support for hormesis would encourage more people to undergo chemotherapy and to clarify which study of atomic bomb survivors he believes supports the theory.]

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  • http://www.mazepath.com/uncleal/EquivPrinFail.pdf Uncle Al

    Required is a huge scale 100-year study of a radiation-sprinkled land and all it inhabitants: flora, fauna, bacterial, and fungal. Chernobyl won,t do, for it has unacceptable male:female and racial ratio of scientists studying it. I volunteer Chicago. Darkest Oakland, and Baltimore.

    • Candice H. Brown Elliott

      I sincerely hope that you were being sarcastic… as those areas are known to have more black people and suggests that you are willing to conduct a potentially genecidal program.

      • Mike Richardson

        I ‘m sure he’s well aware of the demographic make up of those areas, and while he may think it’s funny, I don’t think he was being sarcastic.

  • Chris Murray

    Here’s part of what the EPA formally submitted to the NRC about three years ago, in response to Mohan Doss’s petition to abandon LNT….

    “Of all the agents demonstrated to be carcinogenic, the evidence for LNT is particularly strong for ionizing radiation……………..the available (and extensive) epidemiological data are broadly consistent with a linear dose-response for radiation cancer risk at moderate and low doses. Biophysical calculations and experiments demonstrate that a single track of ionizing radiation………produces complex damage sites in DNA, unique to radiation, the repair of which is error-prone………….no threshold for radiation-induced mutations is expected…….indeed, none has been observed……………..Given the continuing wide consensus on the use of LNT for regulatory purposes as well as the increasing scientific confirmation of the LNT model, it would be unacceptable to the EPA to ignore the recommendations of the NAS and other authoritative sources on this issue. The EPA cannot endorse basing radiation protection on poorly supported and highly speculative proposals for dose thresholds or doubtful notions concerning protective effects from low-level ionizing radiation.”

    That seems clear enough.

  • conor_ob

    Scientific recognition of this predates the Trump Administration. But of course the AP and Discover spin this as a risky Trump initiative, even though the Obama administration began the rulemaking change in 2015. Is there any evidence whatsoever the White House interfered in the process? If not, let’s leave the political spin out of this.

  • Laurenz Hüsler

    The LNT-theory was refuted in the 50ies. Muller had a personal interest to keep the results refuting the theory below the table (it was a test on drosophilae using several doses adding to x instead of a single dosis of x, and the test with several doses led to no variations, while the high dosis led to mutations)
    For example, victims of the two bombs receiving below 100mSv had lower cancer rates than the average of the population. Similar results were found for Mayak victims and for radiation therapy personnel.

    • Chris Murray

      LNT is accepted mainstream science, and a lot of the Muller stuff is irrelevant conspiracy theory..

      The Radiation Effects Research Foundation, the agency actually set up to study the effects of the atomic bombs, found two excess cancer deaths in the below 5 mSv category, and 44 in the 5-100 mSv category.

      (Preston et al (2004) “Effect of recent changes in atomic bomb survivor dosimetry on cancer mortality risk estimates”, Table 3)

      But, of course, they could all be part of the big conspiracy too.

  • Jane Hamber

    I suggest that anyone who wants to lessen the levels of radiation considered safe be ready to expose their family to the new levels as an experiment including any young children and pregnant women. In fact, this should be a requirement for those making such decision that affects millions of Americans. We can start by Trump and family breathing in an extra amount of coal dust and car exhaust fumes.

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