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ScienceMay 6, 2018

Once and for all: can mobile phones give you cancer?

Photo: Getty
Photo: Getty

Year in, year out, the controversy over the possible health effects of electro magnetic frequencies from cellphones and cellular antennas rumbles on. Telecoms writer Paul Brislen takes a deep dive into the evidence.

We’ve been aware of the electro magnetic spectrum since the first cave dweller peeked out and saw a blazing orb in the sky, but we’ve really only been studying it properly since the end of World War II. That gives us a decent amount of awareness about how electro magnetic frequencies (EMF) work and what they do. But there’s still quite a bit of confusion the health impacts of EMF, and none more so than in the world of cellular communications. Cellphones, it seems, still give people the heeby-jeebies.

Given we’re about to see a whole new wave of cellsites being built across the world as 5G rolls out, it’s high time we had a chat about the issues, what to fear and what to embrace and whether or not your phone gives you cancer.

What is EMF anyway?

The radio spectrum is all about wavelengths. To the far left of the spectrum we have the really low wavelength stuff. Things are pretty sluggish down there and you might see one total wave every second or so. There’s not a lot of energy down here and the only measurable physical impact from these types of EMF is a mild heating effect that we’ll talk about in a bit.

From there we work our way up to the excitable end of town – gamma rays. These puppies are very energetic and you get lots of them in a very small space indeed. They are high energy and as such can damage the chemical bonds between atoms, thus producing ions which is why we call the various short-wavelength effects “ionising radiation”.

Waves at that end of the spectrum – the ionising radiation end – cause damage and are cumulative (that is, you get exposed and it stays with you) so that’s why when you get an x-ray the technicians all pop behind a wall of some kind. They’re in there all day – you’re only in and out once or twice a year if you’re particularly healthy.

Waves at the other end – the non-ionising end – don’t have much impact beyond mild heating and it isn’t cumulative. It’s like when you go outside on a hot day and start to warm up – by taking off that jacket you can cool down. You don’t stay hot, it goes away.

The break-even point is around the visible light point in the spectrum – which is handy because you can look at the chart below without risking your eyes being damaged by seeing too much. It’s a non-cumulative chart.


Cellphone emissions and other radio waves sit comfortably within the non-ionising band and as such we’ve not found any physical impact other than mild heating. Nothing. Despite all the hue and cry, the only measurable physical effect is a mild heating, so that’s what we use when we try to limit exposure. It’s not a limit to the radiation, per se – it’s a limit to the amount of heating that can happen.

National Emission Standards (NES) in New Zealand are very strict. Basically they’ve said “how much energy would it take to increase the temperature at the target site by one degree Celsius?” and then said the maximum output is 1/100th of that. For those keen on the detail you can see the NES page here.

New Zealand cellphone companies typically operate their towers at no more than around 2% of that maximum standard, so really the only effect you should experience from standing in the sweet spot near a cellsite is a warming of around 0.0002 degrees Celsius. Heck, let’s push the boat out and say the cellsite is operating at 50% of the allowable maximum – you’re talking about dramatically less of a temperature increase than you’d be able to feel. And assuming you were worried about it, stepping slightly away from the source or (heaven forbid) turning your device off is enough to have you cool down again.

And yet we still have concerns about radio waves. Old fashioned radios (the one we used to call the “wireless” or the “tranny” before finding new uses for those terms) and even newfangled television sets use the same basic model: a large scale transmitter on a hill nearby beams information to a receiver in your house. Cellphones, on the other hand, transmit as well as receive, so clearly there’s something that needs to be investigated.


What’s the evidence?

The first cellphone call was made in 1973. In the 45 years since the number of cellphones has exploded and usage (how long we spend on them) has grown like a weed in the sun. If cellsites affected health outcomes, we should be able to look at brain tumours and other assorted ailments and see a corresponding uptick in terms of incidence.

This chart is from a US study:

((A) Number of wireless subscribers in the United States, 1984–2006. (B) age-adjusted incidence of brain cancer in the United States (2000 population standard), SEER 9, 1984–2006. Source:

And that makes it rather hard to see any causal link at all. Cellphone use has grown, yet the number of brain cancers (the bottom chart, helpfully broken into those most scientific of groups: “Whites” and “Everyone”) has remained pretty flat throughout the same period.

Ah, you cry, but these things grow over time. We won’t know for decades!

Maybe, but you’d still expect to see some uplift by now. The real growth in cellphone use in New Zealand kicked off in the late 1990s and we’ve had no change in the incidence rates for brain tumours during that period.

So, if there’s nothing clear to report in real-world impacts like brain tumours, we’ll need to look to science to see what we can uncover instead.

Lab tests are conducted in (oddly enough) a laboratory. There’s usually a test group (the Victims) and a control group (you Lucky Few). The test group gets the thing you’re trying to test and the control group gets to avoid that thing so you can compare and contrast.

In this case, EMF, the model is to expose some poor creature (normally a rat) to high levels of exposure for prolonged periods to determine just what might happen. This is then compared with a control group of non-exposed rats who live a quiet and peaceful life without any EMF to worry them.

And sadly, this is where we get those crazy newspaper reports that suggest “Science Has Found A Link” and “New Study Proves Cancer Caused by Wifi” and all the rest of it.

When you’re looking at a story about lab-based tests, check for three things. Firstly, that these results are final results and not “preliminary” or “draft” findings. For reasons known only to those involved, scientists like to put out preliminary findings based on a smaller subset of the data they’re working on. I presume it’s to keep the funding flowing but really all it does is generate a lot of mad scientist headlines.

The second thing to look for is whether the results have been peer reviewed. There have been a number of studies that report crazy findings that have to be retracted once the peer review comes out. Peer review is where a bunch of jealous, over-zealous competitors get to crawl all over your study and pull it apart looking for flaws, holes and weaknesses. No peer review: no good.

Photo: Getty Images

The final thing to look for is replication. Has anyone else managed to replicate the study? If not, forget it. Until someone else can say “yes, we also conducted a study and yes, we found a similar result” then it’s an oddball and an outlier.

How outlier?

One recent study (in draft form) found that the rats exposed to EMF did indeed produce more tumours than the control group but that the exposed tumour-riddled rats lived longer than the control group.

“Strikingly, the rats exposed to radiation lived longer than rats in an unexposed group that served as controls. The researchers were at a loss to explain this. Perhaps the radiation reduces inflammation, as is seen in a therapy called microwave diathermy, they said. Or it could just be chance.”

All those crazy headline stories are either taken from drafts, or from studies that haven’t been peer reviewed, or from studies that haven’t been duplicated. Once we get one of those that says “there is a problem, this is our final report, we’ve been peer reviewed and our science is sound and the results have been duplicated by this other study” then we can start to worry. Until then, I would suggest we’re good.

So it’s time for some questions and some answers.

It’s been nearly half a century since the first cellphone call, and cancer and tumour rates are apparently unaffected by the massive amounts of EMF we’re putting out there. So why do the scientists continue?

Good question. Probably it’s for the funding and for the chance to explore the situation further, but some are starting to realise they could spend their entire careers on this and still not come up with any evidence of a problem. One UK group did close down its research after 11 years because it hadn’t found a single provable impact from EMF and the scientists really wanted to get on with something else. The website has completely vanished now so I can’t even share it with you.

Ah, but what about 5G? That’s new and will need to be carefully monitored and reviewed before being released on the public, surely?

Well, yes and no. 5G is short for the “fifth generation” of cellphone technology but frankly that’s all a bit of baloney. It’s a marketing term that really has little to do with the underlying tech. What the marketeers discovered some time ago is that people like to see new things so they can rush out and buy them. Calling the next wave of products “3G” and then “4G” and shortly “5G” helps fulfil that urge, but really it’s the same technology, just somewhat improved.

So, on the one hand yes, it does need thorough investigation but on the other hand you can say that in fact it has had just that.

It’s like saying to Suzuki “Aha, you’ve launched a new model of the Swift and you must now prove everything about cars and the internal combustion engine is safe” as if the car were completely different from its predecessor.

It’s still a car, it still obeys the laws of physics, it still does the same thing the previous model did, but the radio is nicer.

But I use my phone heaps more these days. Surely that means something?

Well if, like me, you’ve given up your landline entirely then yes, this is probably true. When 2degrees launched in New Zealand in 2009 the average mobile user in New Zealand spent one minute per day talking to someone on the phone. That has changed quite dramatically since then. Looking at my own phone, today I made or received 17 phone calls including two radio interviews that each lasted for around ten minutes. My total time on the mobile today is far more than my time spent on my first phone.

But other things have changed as well. Modern phones use a lot less power than their early counterparts. Technology has improved dramatically since the Nokia 2110 I started with and while the battery seemingly lasts no time at all, it’s because I do so much more with my phone now than I did in 1997.

On top of that, my phone can see towers that are much closer because there are more of them, so rather than increasing the power to reach that one distant cellsite, it connects to a much closer site and doesn’t need to use as much energy to do so. It’s a huge irony that the people who want to reduce EMF emissions do so by insisting on fewer towers being built: ideally you want more of them so the thing clamped to your head doesn’t squirt out as much power.

And the third big change since 1997 is that I no longer use my phone the way I did back then. Today I spend most of my time looking at my phone and it’s nowhere near my head. If there were to be a problem I would expect those early users would have experienced the biggest issue because they could only use their phones for talking and that meant holding it to your ear.

I saw a study in the paper that says there’s evidence of a link. What should I do?

Remember our three questions: was the report based on a final result or only a draft? Has the study been peer reviewed yet? Have the findings been replicated by another study? If the answer is yes to all three, do let me know because it’ll be the first.

My friend bought a device off the internet that measures EMF fog and she says it’s everywhere.

Your friend is correct. We are surrounded by EMF just as we are surrounded by light and heat. There’s nothing much you can do about it but that’s OK because there’s nothing much that needs to be done about it. You can certainly build a tin box and sit in that, but do remember, aluminium foil might give you cancer as well. 

My friend lives in <some place> and says the <local council equivalent> has stopped allowing cellsites to be built because there’s a danger.

Sadly, this is probably true but it’s not based on science or on any proven danger, it’s based on fear and the types of stories that encourage people to attend public meetings and scream at officials. I’ve been to these meetings and they’re very emotional affairs with a lot of shouting and little actual dialogue. It’s a shame because people shouldn’t live their lives in fear of the unknown.

If you build a tower near me I will sue you because you’re going to reduce my house’s value.

There’s no real evidence that house prices drop if you have live near a cellsite but this is a very fashionable way to argue with the council about having one built. Much like overhead power lines, once they’re in you hardly even see them but if you put up lots of signs pointing out how angry you are and tell everyone they’re a health risk, well, yes you probably won’t get many people keen to buy your house.

“If you want to be completely outside your phone’s EMF range then hold it more than 5cm from your head.” Photo: Our First Home NZ

Cellphones are supposed to be held two inches away from your head because of the risk but nobody does that and now we’re all going to die of radiation poisoning.

See above for ionising versus non-ionising radiation, but you do raise an interesting point. Distance. There’s this cool geeky science thing called the Inverse Square Law which says power doesn’t drop away in a straight line but instead falls like a stone the further away from the source you are. You can see this with a flashlight – at the torch the beam is concentrated and powerful but the further away you move the less intense it is.

It’s the same with EMF so if you want to be completely outside your phone’s EMF range then hold it more than five centimetres from your head. Personally, I hold mine at arm’s length as I try to focus on the screen but that says more about my eyes than it does about the radiation.

For more on the inverse square law check out this photographer’s video.

Didn’t the World Health Organisation list EMF as a cause of cancer? Are you saying they don’t know what they’re talking about?

In 2011 the International Agency for Research on Cancer (IARC, a division of WHO) released a paper that listed EMF as Category 2B “possible carcinogen” thus generating screeds of mad scientist headlines.

Sadly, IARC didn’t do a lot to explain what it meant by Category 2B “possible carcinogen” because it foolishly believed everyone would read the research and say “Ah, I understand now.”

IARC has five categories for things that relate to whether or not they’re carcinogenic. – Category 1: carcinogenic to humans. Definitive, proven, absolutely will give you cancer. There are 120 items in Category 1 and they’re things you’d expect. Asbestos. Formaldehyde. Smoking. Ethanol in alcoholic beverages. Wait, what?

Category 2 is actually two categories. 2A is “probably carcinogenic” to humans and includes 81 items. These are things that show “limited” evidence of being carcinogenic but “sufficient” in animal studies. Most of them are chemicals you probably avoid anyway: Acrylamide, Ethylene dibromide, other things that I really can’t explain to you.

We’ll come back to 2B in a moment.

Category 3 is things that are not classifiable. This means that the evidence is “inadequate” in humans or “inadequate or limited” in animals and it’s probably down to the number of tests that have been conducted. Does mall lighting give you cancer? Well, we’ll probably never know but fluorescent lighting is one of the 502 items in this category, along with tea. Ah, tea.

Category 4 is things that won’t give you cancer. There’s one thing in this category – Benz[j]aceanthrylene. I do not know what this is but you would think you’d be OK to drink it, however it’s sold as Caprolactam and is predominantly used in the manufacture of nylon. Ew. 

Category 2B is “possibly carcinogenic to humans” and contains 299 products, including coffee, pickled vegetables, carbon paper, gasoline exhaust, talcum powder and the nickel that goes into making coins, as well as EMF.

To quote from IARC itself

“This category is used for agents for which there is limited evidence of carcinogenicity in humans and  less than sufficient evidence of carcinogenicity in experimental animals. It may also be used when there is inadequate evidence of carcinogenicity in humans but there is sufficient evidence of carcinogenicity in experimental animals.”

So, there’s little evidence of anything being carcinogenic but we don’t want to rule it out so… it’s a 2B.

Don’t think IARC didn’t get quite a bit of stick for this. 

To quote: “Saying that something is a “possible carcinogen” is a bit like saying that someone is a “possible shoplifter” because he was in the store when the watch was stolen. The real question is what is the evidence that cell phones actually cause cancer, and the answer is — none that would persuade a health agency.”

That was in 2011, hasn’t there been more study done since then?

Why yes, there has. The largest study ever undertaken – the so-called “million woman studywhich was a collaborative study of one million women in the UK aged 50 and over. It looked at all kinds of things, and one of those was the use of cellphones and the incidence of brain cancers.

It’s a fascinating study all round but the relevant bit is this: “In this large prospective study, mobile phone use was not associated with increased incidence of glioma, meningioma or non-CNS cancers.”

There has been a recent rat study that says we’re all going to get some obscure tumours called schwannomas in our hearts.

Well, sort of.

The study has yet to be peer reviewed or replicated (ding ding ding) but does cast an interesting light on the subject. In this study, rats were exposed to very high levels of EMF for their entire lives and yes, in male rats a statistically interesting number developed these very rare tumours called schwannomas.

However, the rates of exposure were up to 1000 times higher than you’d get from a cellphone and ran for 19 hours a day from before the rats were born until they died a natural death.

Only the male rats developed these schwannomas, and yet they also lived longer than the control group. Needless to say, the jury is out until someone can a: replicate it and b: work out what the connection is (if any) with EMF exposure.

So, to recap. Despite billions of users around the world using mobile phones, over a period of nearly 50 years now, with increasing levels of use and coverage, there are no corresponding increases in the number of cancers we would expect to see. Having exhausted the “expect to see” list, we’ve conducted dozens if not hundreds of studies into any other affects that can be attributed to cellphones, WiFi or cellsites and found no evidence of any physical impact whatsoever. On top of that, we’ve got the world’s largest study ever which can find no trace of a connection between a range of cancers and tumours and the use of cellphones.

If you’re still concerned, have a look at the Ministry of Health pages and see what the MoH says.

Remember, if you’ve heard about a study that says something controversial, check to see if it’s a draft finding, or if it’s been peer reviewed, or if it’s been corroborated by another study and if not, feel free to carry on regardless.

I know I will.

The Spinoff’s science content is made possible thanks to the support of The MacDiarmid Institute for Advanced Materials and Nanotechnology, a national institute devoted to scientific research.

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