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expert reaction to study on mobile phones and rats

National Toxicology Program report shows that male rats who were exposed to high levels of 2G and 3G radio frequency developed cancerous heart, adrenal gland and brain tumors.


Prof Kevin McConway, Emeritus Professor of Applied Statistics at The Open University, said:

“It’s good that the US National Toxicology Program (NTP) has researched these issues. But these findings don’t cause me any real concern about health risks to humans from mobile phone use. There has been much previous research on this topic, most of which has found no evidence of any risk to humans, and some of which has found very limited evidence of a small risk with very heavy phone use. I don’t think that these NTP results have moved us on from that yet, and that’s generally because they were not designed to investigate those risks. They were looking at something else.

“The results are from experiments in which non-human animals (rats and mice) were subjected to radiofrequency radiation for 9 hours a day, every day for their whole lives, starting before birth for the rats and at a very young age for the mice. That’s way more use than most people make of their phones. I’m no physicist, but I understand from information in the reports that the lowest radiation levels used were equal to the safety limits imposed on mobile phone manufacturers, for the radiation when one is actually using the phone (and the stated radiation values for my own phone, for instance, are considerably less than those limits). The higher doses for the animals were four times those limits. What’s more, the rats and mice were exposed to the radio waves throughout their bodies, and that’s not much like the radiation exposure to humans when they use their phones, which will be mostly in particular parts of the body near the phone. It’s certainly not yet obvious how these high-dose results in rats and mice might tell us anything about normal levels of human mobile phone use.

“What these studies have told us is that, under these particular conditions which don’t match human phone use, in particular animals that aren’t humans, there is clear evidence that the radio waves led to an increased risk of a particular kind of tumour in the heart, but only in male rats. Evidence for other increased risks as an effect of the radiation, in other parts of the body, or in female rats or in mice of either sex, was either considerably weaker, or non-existent.

“Does this tell us anything useful? Well, it establishes that, under certain conditions radiation of the same kind as produced by some mobile phones, but generally much stronger and much longer lasting, can lead to an increase in a certain type of tumour in certain rats. That’s worth knowing, but it’s a bit like a hypothetical experiment where rats are run over by heavy boulders. That would doubtless establish that heavy boulders have the potential to harm rats, but it doesn’t tell us anything at all about the risk to humans arising from the existence of heavy boulders in the world. To investigate that risk requires a completely different type of research.

“So here we have a study that found evidence, some of which is pretty weak, of effects of mobile phone radiation on tumours in rats, and which tells us pretty well nothing direct about risks of actual phone use in actual humans. I’m not going to stop using my mobile phone in the light of this.”


Declared interests

Prof McConway is a member of the Advisory Committee of the Science Media Centre

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