Nuclear Power Plants and Childhood Leukaemia–End of the Debate?

A common claim by opponents of nuclear power is that nuclear power plants are directly linked to higher rates of childhood leukemia. For example, Greenpeace frequently references such claims on their website and branded publications such as here, here, and here. It appears that in some cases, the research on which these claims are based has been misunderstood:

A good example is this 2010 Greenpeace story, quoting a report according to which a 2008 study published in the journal Radiation Protection Dosimetry supports the claim of increased cancer rates around nuclear power plants because of radioactive emissions from these facilities.

In fact, the study does no such thing. Instead, the authors note that childhood leukemia rates around nuclear power plants are generally not higher than elsewhere, with three notable exceptions: Sellafied and Dounreay in the UK, and Krümmel in Germany. But rather than attributing those slightly increased rates of childhood leukemia to radiation from these sites, the authors state that they find the hypothesis that cases of childhood leukemia may be linked to a yet unidentified infectious agent most convincing. After all, if radiation were the cause, then one would expect to find higher rates around most nuclear sites, not just 3 out of 49 in total.

Examples where anti-nuclear activists seem to have misread scientific studies on the effects of nuclear radiation abound, and are too numerous to detail in a single blog post. In too many cases, the studies say the polar opposite of what is claimed they say.

However, there is one prominent exception: the famous 2007 KiKK study (Epidemiologische Studie zu Kinderkrebs in der Umgebung von Kernkraftwerken). This study, sponsored by the German Federal Office for Radiation Protection (BfS), did indeed make the argument that

there is a correlation between the distance of the home from the nearest NPP [nuclear power plant] at the time of the diagnosis and the risk of developing cancer (or leukaemia) before the 5th birthday.

However, the authors of the study have been quite clear that they do not attribute these findings to radiation from the nuclear facilities:

This study is not able to state which biological risk factors could explain this relationship. (p. 19)

Furthermore,

Exposure to ionising radiation was not measured or modelled. (p. 19)

And

This study can not conclusively clarify whether confounders, selection or random influences play a role (…).

In 2008 the authors published a follow-up paper, where they confirm their findings, but once more point out that

The result was not to be expected under current radiation-epidemiological knowledge. Considering that there is no evidence of relevant accidents and that possible confounders could not be identified, the observed positive distance trend remains unexplained.

In short, they found something, but have no idea how to explain it.

To make the claim, as many in the anti-nuclear community have since done, that the KiKK study shows nuclear power plants are responsible for increased childhood leukaemia rates in their vicinity is simply not supported by the KiKK study itself.

But nonetheless, the findings were interesting enough for the German Commission for Radiation protection to do a systematic assessment of the KiKK study. Some of the findings were nothing short but astonishing. Apparently, it was found

an increased leukaemia risk for children who lived in areas in which nuclear power plants were planned but never built. (p. 29)

Even more surprisingly,

the risk was similar to that found in the vicinity of existing nuclear power plants. (p. 29)

Since nuclear power plants that have not yet been built can hardly pose a radiation risk to the public, the authors conclude that, maybe,

nuclear power plants may tend to be built in areas which, for reasons that have not yet been understood, have a higher risk of childhood leukaemia. (p. 29)

Why sites that would be good locations for nuclear power plants tend to be associated with higher rates of childhood leukemia will probably remain a scientific puzzle for years to come. One thing, however, seems to be clear: it’s not the nuclear power plants.

Researchers in other countries have come to the same conclusion. For example, the UK Committee on Medical Aspects of Radiation in the Environment (COMARE) has studied various aspects of radiation health effects since 1985, and published 14 comprehensive reports by now, including one on childhood leukaemia around nuclear power plants in Great Britain.

While stressing – with good reason – that it is necessary to continuously monitor for any possible negative health effects from nuclear power plants, the authors state unambiguously there is

no evidence that there is an increased risk of childhood leukaemia and other cancers in the vicinity of NPPs due to radiation effects.

As for Canada, the situation is no different: a systematic review of current data and scientific research by the Durham Region Health Department found that cancer rates around two of Canada’s major nuclear sites in Ontario

did not indicate a pattern to suggest that the Pickering NGS [nuclear generating station] and the Darlington NGS were causing health effects in the population.

It really couldn’t be any clearer: nuclear power plants in Canada, the UK, and Germany do not cause childhood leukaemia or other cancers.