Mobile phone radiation shouldn’t harm humans, new study on rats suggests

If you keep something in your pocket or pressed to your ear for hours at a time, it would be preferable if said devices were not carcinogenic. Unfortunately, such hard and fast assurances have been hard to come by, partly because science rarely deals in definites, but also because it’s really hard to test: long-term studies are tricky because we haven’t actually been using them that long. In the short term, however, a new study on rats suggests we should be okay. In the short term at least. Probably.

Why the hesitancy? Well, chiefly because not all the rats came out of the study in tip-top shape. One of the studies suggested that male rats grew tumours around their hearts. Female rats, on the other hand, had no such affliction, and neither gender suffered any ill effects in a second study, muddying the waters somewhat.

That doesn’t sound completely reassuring, except it’s important to emphasise that these plucky rats were exposed to a dose of radiofrequency radiation (RFR) much, much higher than even the most smartphone-addicted human. To be precise, rather than scaling down an iPhone to paw size, these rats had their entire bodies doused in the same waves (1.5 to 6 watts per kilogram) for nine hours per day, for up to two years. And bear in mind that a two-year-old rat is equivalent to a 70-year-old human.

“The levels and duration of exposure to RFR were much greater than what people experience with even the highest level of cell phone use and exposed the rodents’ whole bodies. So, these findings should not be directly extrapolated to human cell phone usage,” said John Bucher, Ph.D., NTP senior scientist. “We note, however, that the tumours we saw in these studies are similar to tumours previously reported in some studies of frequent cell phone users.”

Not only that, but there are three more caveats worth noting. The first is that the studies involved 2G and 3G signals, not the current generation 4G or upcoming 5G signals, so any risk specific to LTE will not have been noted. But more importantly, rodents aren’t always a good analogue for human biology – if they were, we’d have cured a lot more diseases than we have, with treatments that work on rats often falling short when extended to human trials. Finally, with rats’ lifespans rarely exceeding three years, and humans routinely living into their 70s, there’s only so much this can say about long-term impacts.

Still, the Food and Drug Administration (FDA) seems content with the study in the short term while it continues to examine the wider evidence. “I want to underscore that based on our ongoing evaluation of this issue and taking into account all available scientific evidence we have received, we have not found sufficient evidence that there are adverse health effects in humans caused by exposures at or under the current radiofrequency energy exposure limits,” the statement from FDA director Jeffrey Shuren reads. “Even with frequent daily use by the vast majority of adults, we have not seen an increase in events like brain tumours. Based on this current information, we believe the current safety limits for cell phones are acceptable for protecting the public health.”

This advice was echoed by Dr Otis Brawley, chief medical officer of the American Cancer Society. “These draft reports are bound to create a lot of concern, but in fact they won’t change what I tell people,” he told the Associated Press. “The evidence for an association between cell phones and cancer is weak. And so far, we have not seen a higher cancer risk in people.

“But if you’re concerned about this animal data, wear an earpiece.”

For your own reference, not all smartphones are created equal in terms of their radiation output. This chart, from our friends at Statista, gives you an idea of the disparity between handsets.