I got my first cell phone about 30 years ago – one generation ago in human time and five generations in transmission technology. And it seems that every few years – especially whenever a new transmission technology is developed – there’s a flurry of concerns about the harmful effects of cell phone radiation. So maybe this is a good time to take a look at the science behind cell phones and cancer.
(Source: US EPA https://www.epa.gov/sites/default/files/2017-05/electromagnetic-spectrum_0.png)
Here’s where some of the misunderstandings begin – to a scientist or an engineer “radiation” has a different meaning than it does to an ordinary person. When someone with a scientific background uses the term they’re speaking about the energy that’s given off by one object and transmitted through space to another. So scientists and engineers talk about thermal radiation, radio and microwave radiation, visible light radiation, and even gravitational radiation – as well as x-ray, gamma ray, cosmic, and alpha, beta, and gamma radiation. The thing is, only the second group of these has enough energy to remove an electron from an atom – to cause an ionization – and it’s the ionization that’s the first step in causing cancer. This means that the first types of radiation (thermal, etc) cannot cause cancer and the second group can.
The reason for this is actually fairly simple – it takes a minimum amount of energy to cause an ionization and, absent ionization, radiation can’t initiate the sequence of events that might lead one day to cancer. Anything with less energy can’t do the trick.
Think about trying to throw a ball onto the roof of, say, a school. If the roof is 40 feet off the ground then you have to throw the ball hard enough to reach 40 feet in the air. If you can’t throw the ball with enough energy to get 40 feet in the air it’s never going to land on the roof, no matter how many times you throw it. Electrons around atoms are the same – it takes a minimum amount of energy to strip an electron from an atom and nothing with less energy is going to cause an ionization. Radiation with less energy than ultraviolet isn’t energetic enough to cause an ionization – and cell phone radiation (including 5G) lacks the energy to ionize an atom.
OK – so what about all the studies showing that, in spite of this, cell phones do cause cancer? And this is somewhat personal for me – not only do my wife and I, our kids, parents, and…well…our entire extended families use cell phones on a regular basis, but one of my relatives developed parotid gland cancer on the side of her neck that she normally holds her cell phone on. And then there’s the occasional paper in the medical literature as well – what about them?
The thing is, there’s not a single one of these papers that’s conclusive. What I mean by that is that, for every paper that shows a slight increase in cancer risk among cell phone users there are others that show no change at all. And the changes that they do show are tiny – smaller than the normal variability in the data, which means that they’re not very convincing. Consider – say there’s a group of six people. On average, about half the people in the world are men and the other half are women. But say that this group has four women and two men – 33% of the group is male and 67% is female. Is this significant? Should we start looking for a reason for this big shift in population statistics? Well…no. The change of a single person in a small group might cause what appears to be a dramatic change in the statistics – one that might not be borne out as the group grows in size. Think of a larger group – 30 people, say – with one extra woman. Now we’ve got 16 women and 14 men (53% and 47% respectively). In an even larger group of 100, that one extra person brings the numbers of 51% and 49% – even less impressive. The moral of the story is that, in a small study population, a very small actual change can look impressive – more impressive than is warranted.
Now think about a cancer that affects only, say, one person in 10,000. This means that if you’re looking at 10,000 people then you’d expect to see a single of these cancers. So what if you see two such cancers in a group of people who drink orange juice – does that mean that orange juice causes cancer? Or could it be that it’s just a fluke – that just one extra case, even of a rare cancer, isn’t that big a deal? And in fact, it’s the latter; a single extra case – even if it causes the expected number of cases to double – simply isn’t enough to show cause and effect.
One of the more recent studies seemed to show an increase in some very rare cancers among rates that were exposed to cell phone “radiation” – but this study suffers from the problems of small-number statistics; these were pointed out by internal reviewers when the study was first done. And, of course, there’s also the fact that cell phone “radiation” can’t ionize atoms so they can’t initiate the process that leads to cancer – and the report’s author doesn’t provide any plausible explanations as to how it might. But there’s more than this.
One factor is that this study exposed the rats to very, very high levels of exposure – far higher than any user would be exposed to. And dose rate makes a difference – just as the rate at which you add water to a bathtub makes a difference. At a lower dose rate, the body can repair damage much more effectively than it can when its repair mechanisms are overwhelmed. And, of course, there’s the minor point that rats aren’t people and they might not respond the same way that we do to any exposure. So that makes it hard to apply these results to humans as well.
But, then, the study also exposed the rats to the same dose across their entire bodies, which is something that doesn’t happen when we’re talking on the phone. If you’re holding the phone in your right hand then your right ear, part of the right side of your head, and maybe the right side of your neck are closest to the phone and will get the highest dose. The heart (where some of the rats developed tumors) is at least 10 times as far from the phone and will receive less than 1% of the dose of the head and neck – not to mention that the intervening tissue will reduce exposure even more by absorbing still more of the radiation. So for this study to be at all relevant to humans, our hearts would have to be amazingly sensitive to the effects of radiofrequency radiation – something that has never been noted (or even postulated).
The bottom line is that this report adds nothing compelling to the arguments that cell phones might cause cancer. Or, to put it another way, I’m still using my phone and I’m not worried about my kids using theirs. As long as they don’t text while driving, that is.