There is an ongoing scientific discussion about the safety of long term cell phone use. The primary question is whether or not long term exposure to non-ionizing radiation can increase the risk of brain cancer. There are further questions about whether or not such radiation can cause any health problems or symptoms.
As with any complex area of scientific research, perhaps the best way to evaluate the question is to put together a panel of experts to review all the existing evidence and then come up with a consensus opinion about that evidence. This is no guarantee of being right – the primary issue that tends to come up with such expert panels is that they were systematically biased toward one side of the debate. But assuming no major asymmetry in the constitution of an expert panel, they are an excellent way to evaluate the current state of the evidence on a specific question. Even better, of course, is when multiple independent panels all agree.
Recently an expert panel for the UK’s Health Protection Agency (HPA) reviewed the evidence for cell phone safety concluded that there is no clear evidence for any harm. This is good news. Their findings are similar to other reviews of the evidence, although often there is a difference in emphasis. For example, last year the International Agency for Research on Cancer (IARC) reviewed the same evidence and concluded that:
“the evidence, while still accumulating, is strong enough to support a conclusion and the 2B classification. The conclusion means that there could be some risk, and therefore we need to keep a close watch for a link between cell phones and cancer risk.”
They are not really saying anything different from the HPA – both groups concluded that there is no clear evidence of risk, but that further monitoring is prudent. The HPA, however, chose to emphasize that there is no conclusive evidence of risk, while the IARC chose to emphasize that there is no conclusive evidence that there is no risk. There classification means that there may or may not be a risk, but further research is warranted. Meanwhile the FDA has concluded that: “the weight of scientific evidence has not linked cell phones with any health problems.” The Federal Communications Commission has this to say:
“There is no scientific evidence that proves that wireless phone usage can lead to cancer or a variety of other problems, including headaches, dizziness or memory loss. However, organizations in the United States and overseas are sponsoring research and investigating claims of possible health effects related to the use of wireless telephones.”
These all sound like variations of the same conclusion – there is no clear evidence of harm or risk, but we should continue to do research and monitor the results. Overall there is more caution when children are concerned, because there are fewer studies, children’s heads are smaller, and if cell phone use is started at a young age then lifetime use will be greater. Still there is no evidence of harm, but there are a priori reasons for greater caution.
Getting back to the new review by the HPA, here are their key conclusions:
- The evidence suggests that RF field exposure below guideline levels does not cause symptoms in humans and that the presence of RF fields cannot be detected by people, including those who report being sensitive to RF fields.
- A large number of studies have now been published on cancer risks in relation to mobile phone use. Overall, the results of studies have not demonstrated that the use of mobile phones causes brain tumours or any other type of cancer.
- As mobile phone technology has only been in widespread public use relatively recently, there is little information on risks beyond 15 years from first exposure. It is therefore important to continue to monitor the evidence, including that from national brain tumour trends. These have so far given no indication of any risk.
- Studies of other RF field exposures, such as those at work and from RF transmitters, have been more limited but have not given evidence that cancer is caused by these exposures.
- Research on other potential long-term effects of RF field exposures has been very limited, but the results provide no substantial evidence of adverse health effects; in particular for cardiovascular morbidity and reproductive function.
There are several types of evidence that address this question. The first is the basic science plausibility of health effects from non-ionizing radiation. By definition, non-ionizing radiation (like radio-frequency radiation used by cell phones) is not energetic enough to break chemical bonds. It therefore should not cause DNA mutations, which is believed to be the primary mechanism by which high energy radiation causes mutations that lead to cancer. Some scientists have concluded from this that cell phones cannot possibly cause health effects, and while this conclusion may be true
it is a bit premature. More subtle biological effects are not likely but are also not completely implausible. There is some local tissue warming, for example. The magnitude of this effect is very small, but it is not zero. My own feelings on the question is that biological effects from cell phone radiation is very unlikely, but it would be premature to declare them impossible. Therefore clinical research into the effects of chronic cell phone use are warranted.
There are two basic types of clinical evidence – observational and experimental. We do not have any experimental data on cell phones and humans because such studies are both unethical and impractical. You cannot randomize study subjects to either be exposed to or not be exposed to a potential environmental risk factor. You can’t force people to use cell phones (or smoke, or eat a possible toxin, etc.) to see if they cause harm. So we have to get by with observational data.
There have been a number of observational studies of cell phones and brain cancer. They generally take two forms: either looking at people with and without brain cancer and then finding out their cell phone use history, or dividing people into groups based on their cell phone use and then following them for their subsequent rate of brain cancer. We can also look at overall brain cancer incidence to see if it correlates with overall cell phone use.
These are the studies that the above expert panels and agencies have been reviewing, and which do not show a clear correlation between cell phone use and brain cancer. One limitation of such studies is that they cannot be extrapolated beyond the duration of observation. We now have about 15 years of observational data for cell phone use, so our conclusions about safety from this data are limited to about 15 years. We cannot know that cell phone use is safe when used for 20 or 30 years until after we have observed effects for that long.
Another way to look at this type of data is this – if we take the hypothetical situation that there is zero health risk from cell phone use, what would our observational data look like? We would never be able to prove that the risk is zero. Rather, the more data we gather then the smaller the possible remaining risk (risk that is too small to be detected by the current data). This uncertainty will approach, but never quite reach, zero. So we can never prove a zero risk, but we can increase our confidence that the risk is too small to worry about. Also, the longer we gather data and make observations then the longer the period of exposure over which we can say there is likely no risk.
Of course if there is a small risk from cell phones the data will look exactly the same, until we gather enough data to detect with statistical confidence this small risk.
Agencies and panels who have reviewed the data all agree that we have not detected a statistically significant risk from cell phone use out to the current limits of the data – 15 years. They also all agree that we should continue to conduct research and monitor cancer rates. Where there is some difference is in the application of the precautionary principle. Given this current state of the data, how cautious should we be about the potential health risks of cell phones. There is no objective scientific answer to this question. This comes down to philosophy and personal choice. How valuable, for example, are cell phones? Many people find their convenience worth even a known small risk, let alone a possible but unproven small risk. We also have to consider how many lives are saved by the availability of cell phones in emergency situations.
Cars are an obvious analogy to cell phones. In the US there are about
40,000 motor vehicle related deaths per year. This is far more than the possible remaining risk from cell phone use, given current evidence. Yet, we accept this risk because of the convenience that motor vehicles provide, in addition to being a critical part of the infrastructure of our modern society.
It is interesting to think about what risk you would accept from cell phone use. Let’s say that eventually we find there is a small increased risk of cancer from cell phones. At what point would you conclude that this risk is high enough to stop using cell phones? I think there is sufficient evidence to conclude that we are already below that number for me personally. Even if there is a small risk, it is too small to worry about. But I also welcome reassurance from further research.
This is another issue where the science doesn’t really matter. Plaintiff lawyers want to be able to sue cell phone companies on behalf of everyone who has, or might have, cancer. Therefore this issue will never go away. It’s just too potentially lucrative. Moreover, plaintiff lawyers are big campaign donors, so there will always be political interest in keeping the “controversy” alive.
I have to disagree with you here. I think you are being overly cynical. Lawyers still need experts to make such cases, and if there is sufficient evidence for a lack of harm, that can kill such cases. Historically, for example, there used to be many lawsuits claiming that mild trauma caused later cancer. Studies clearly showed this is not the case, and those lawsuits stopped. Evidence that cerebral palsy causes birth complications, rather than the other way around, dried up law suits against obstetricians for cerebral palsy.
What some lawyers do is exploit preliminary research or scientific uncertainty. When quality scientific evidence comes back negative, however, they move on to the next thing.
Easy: if cellphoones causes cancer, there must be a correlation with right hand / left hand use.
http://www.ncbi.nlm.nih.gov/pubmed/19581357
This has been done, but not well, so recall bias can be the cause of a possible association. Better studies are needed.
Same issue in the Interphone study. They found significantly increased risk of acoustic neuroma especially on the side of the head where the phone was used, but only for subjects who reported spending a lot of hours on the phone.
http://www.ncbi.nlm.nih.gov/pubmed/19513546
I meant to post the link below, but the one above is good too.
http://www.ncbi.nlm.nih.gov/pubmed/21862434
“At what point would you conclude that this risk is high enough to stop using cell phones?”
You wouldn’t have to stop using cell phones completely. Just using a headset eliminates most of the risk. Maybe think twice before wearing smart glasses with a built-in cell phone that’s on all the time.
“We also have to consider how many lives are saved by the availability of cell phones in emergency situations.”
This is like arguing that we shouldn’t ban DDT use in agriculture because it has saved lives from malaria. Carrying a cell phone in case of emergency doesn’t mean talking on it for hours.
well, yes, we shouldn’t ban DDT, because the overall balance is positive, too.
Has the risk been quantified? What’s the upper bound on the risk ratio?
If something is found to cause cancer in rats, but has not been shown to cause cancer in humans, would you be comfortable using it? Some people would be, others wouldn’t. I’d want to know why it causes cancer in rats but not in humans.
Oh no, the “possible effects” line – it’s fishing for perpetual funding for an issue which had been resolved long ago. You’d think with the growth in cellular phone use in the past 30 years alone we’d see a very strong link between cell phone deployment and brain cancer – but no, and yet the myth persists.
If cell phones increase cancer risk after 30 years of regular use, you’d barely start to see any link.
30 years, 50 years – there is not even any remotely plausible mechanism proposed so we’re left with the “magical cellular damage” theory. In the meantime some people genuinely believe that the phones increase the risk of cancer – and yet the same people likely ignore the evidence that using the infernal radios while driving significantly increases the risk of an accident.
About the mechanism, I mentioned this model before.
http://arxiv.org/abs/0910.5294
You weren’t impressed, but I wonder if this is the mechanism causing DNA damage in rat brain cells.
http://informahealthcare.com/doi/abs/10.1081/JBC-200055046
They say a 2.45 GHz signal caused DNA to break, but adding noise blocked the DNA breaks. Sounds like some kind of resonance.
Cell phones do not emit terahertz radiation
Alexandrov did not actually conduct an experiment. He conducted a mathematical simulation. Experimental verification has not been done. There is no reason to believe that under normal conditions damage to DNA is at all likely to occur. The reason why is because terahertz radiation cannot penetrate more than a few millimeters into tissue.
Cell phones are safe.
Airport security scanners are safe.
Did you miss the experiment on rats?
“Did you miss the experiment on rats?
I missed any kind of causal mechanism sufficiently energetic that it could cause a point mutation which would then lead to cancer.
Ionizing radiation
“…low-energy non-ionizing radiation may damage molecules, but the effect is generally indistinguishable from the effects of simple heating”
Warming up rat brains, or any brains, isn’t going to do it. Here is something the kids can try at home. Hold a brick up to your head for a few hours. The tissue in your head next to the brick will heat up but I can assure you that bricks are safe and do not cause cancer.
THz radiation is non-ionizing. It’s between microwave (GHz) and IR.
Alexandrov modeled it and found that it causes “linear instabilities” that “significantly interfere with the naturally occurring local strand separation dynamics of double-stranded DNA, and consequently, with DNA function” after extended exposure.
That was all theoretical, but then there was an experiment with rats, where extended exposure to microwaves broke DNA strands, but this was tempered by adding a noise signal, which may disrupt resonances.
The millimeter wave airport security scanners don’t subject people to extended exposure.
I wasn’t impressed because the proposed mechanism is magic. Some ad hoc mathematical model was used to claim that there is an effect – and strangely enough the effect (which was presumably observed somewhere) was not even established. There were some claims of course, but they fell far short of establishing anything. If I were a referee my comments to the editor would have been something along the lines of “more work needs to be done to establish the claims of observed DNA damage on which the work is based”. I am always bemused by scientists attempting to explain a phenomenon which they haven’t even established to exist.
All systems have noise; you can certainly add more noise, but you can’t have a noiseless system. If there were a resonant effect of any kind, the result of more noise at best would be a weaker effect, not no effect. The fact that it is claimed that the addition of noise made the effect go away suggests that there was no effect to begin with and more work should have been done to demonstrate the existence of the claimed effect.
@Max:
You wrote, “Just using a headset eliminates most of the risk.” How do you know that? What evidence do you have for the relative risks of talking on a cell phone without a headset vs. talking on a cell phone with a headset?
“Has the risk been quantified?” Yes and no. Yes, because after repeated, large, high-quality studies, the evidence strongly converges on no detectable risk. No, because without a randomized, placebo-controlled, double-blinded trial, you can’t ever get to zero. Even then, there’s always the possibility, however remote, that some small sub-set of the population that is unusually susceptible to harm from cell phone use.
“I’d want to know why it causes cancer in rats but not in humans.” So would I. But I’m not aware of any research that shows that cell phone use causes cancer in rats. What evidence are you aware of that shows adverse effects from cell phone use in animal trials?
“If cell phones increase cancer risk after 30 years of regular use, you’d barely start to see any link.” That’s true. But is there any reason to think that cell phones do increase cancer risk?
There doesn’t appear to be any plausible mechanism. There doesn’t appear to be any plausible a priori reason to suspect an increased cancer risk. The available evidence seems to strongly converge on a finding that even if there is a risk, it is so small as to be undetectable, and indistinguishable from no risk whatsoever.
I suppose you could refuse to use any new technology, eat any new food, use any new drug, use any new cosmetic product, and on, and on, unless it has already been in widespread use for at least one human lifetime. That seems a bit extreme to me, and perhaps I am misunderstanding your point, but that seems to be the position you are arguing for.
Using a headset reduces risk because moving the antenna away from your head greatly reduces the absorbed radiation. Picture it by holding a small light bulb up to your hand and moving it away.
Here’s some evidence of adverse effects on rats.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1241519/
Here’s evidence of “increased risk of acoustic neuroma associated with mobile phone use of at least 10 years’ duration.”
http://www.ncbi.nlm.nih.gov/pubmed/15475713
@Max:
“Using a headset reduces risk because moving the antenna away from your head greatly reduces the absorbed radiation.” Except doesn’t using a Bluetooth earpiece actually put a radio antenna closer to your brain? Or are you advocating wired headsets (like Phil, below)? And, again, what evidence is there that using a headset actually lessens the risk, whatever it may be.
“Here’s some evidence of adverse effects on rats.”
Thanks. I wasn’t aware that there had been any studies that indicated an increased cancer risk in rats. Now I know there’s at least one. Do you know if it’s been replicated?
“Here’s evidence of “increased risk of acoustic neuroma associated with mobile phone use of at least 10 years’ duration.””
Ok. Again, do you know if this study been replicated?
There’s a problem with looking at a single study in isolation. Let’s say you look for a correlation between cell phone use and 20 different kinds of cancer. At the usual p=.05 level, just by chance you’d expect to find a “significant” correlation with one type of cancer. If multiple studies of the same kind kept finding correlations with the same type of cancer, you’d be on to something. But if those studies kept finding no correlations or weak correlations with different cancers, you’d be looking at what you’d expect from chance – indistinguishable from there being no actual correlation, much less a causal relationship.
My understanding is that (vastly simplified), the literature on cell phones and cancer risk looks like the second case rather than the first. There are studies that show an increased risk for a particular type of cancer or other adverse effect under particular conditions, but the findings aren’t replicated across a range of studies. The evidence of all of the studies taken together converges on the risk being non-existent or so small as to be unmeasurable.
A Bluetooth signal is much weaker than a cell phone signal that has to reach a tower. In any case, unless you use a speakerphone or texting, you’ll have a speaker and wires up to your ear, so a wired headset would be the safest bet, not to mention that they’re cheaper and don’t need to be charged.
The rat study I cited talks about nerve damage, not cancer, which is a reminder that cancer isn’t the only possible problem.
Here’s another one that Skeptoid referenced.
http://informahealthcare.com/doi/abs/10.1081/JBC-200055046
They found that a microwave signal breaks DNA in rat brain cells.
My original point about rats was more general though. I was thinking of food additives and saccharin.
Here’s what the IARC report said about the risks: “The Working Group did not quantitate the risk; however, one study of past cell phone use (up to the year 2004), showed a 40% increased risk for gliomas in the highest category of heavy users (reported average: 30 minutes per day over a 10‐year period).”
http://www.iarc.fr/en/media-centre/pr/2011/pdfs/pr208_E.pdf
The Mayo Clinic lists “heavy use of cellular telephones” as one of “possible but unconfirmed risk factors for acoustic neuroma.”
http://www.mayoclinic.com/health/acoustic-neuroma/DS00803/DSECTION=risk-factors
As you say, with no evident means of effect and almost no statistical evidence, it’s hard to say what precautions should be taken. Removing the mobile phone from your head via a wired headphone may be an obvious choice. Wired headphones have been in mass use since WW2 and one assumes there is data on their usage. Bluetooth, not nearly as much.
My first response was, the problem is already solved, just wear your Tin Foil Hat http://en.wikipedia.org/wiki/Tin_foil_hat . Then I realized it’s probably a bad idea, since you’d stand out ( even wearing something as professionally made as a collander) for the following reason: http://www.youtube.com/watch?v=zekiZYSVdeQ .
Ultimately, I scrapped those solutions and decided the issue of cell phone radiation was mostly hyperbole and hysteria. Relying on the “Null Hypothesis”, that is, is there strong or medium evidence to suggest a problem? Right now the best evidence is that there’s no adverse effects. ( @Max “The rat study I cited talks about nerve damage, not cancer, which is a reminder that cancer isn’t the only possible problem.” We need to be consistent and methodical. Attributing all sorts of ills to cell phone radiation isn’t science, it’s hysteria; no offense.)
I think the problem here is where the burden of proof lies. Is it with those proposing cell phones should be used, or those proposing that they may pose a health risk. Both these positions as stated, are hypothesis in need of verification, but I can see how from the standpoint that they may pose a health risk, one might decide that cell-phones need to be proven safe, rather than assumed with a “Prove me wrong” attitude.
It’s not hysteria, it’s similar to the procedures undertaken to assess food additives, drugs and medical treatments. One can’t assume something is safe, until a low risk has been shown. As Novella pointed out, with the limited timespan for the data, it’s hard to establish the upper bounds of risk over a potential lifetime of usage.
Personally, I worry that they may be doing something. But it’s use outweighs a vague undefined risk.
The thing is, a lot of work had been done to ensure the safety of the devices and there is no experimental evidence to suggest that there is a problem. Decades have gone by and there is still no evidence of a problem. We can only test the safety of a product using current knowledge about things; on rare occasions we later find a problem with something. I remember the TV hysteria and the microwave ‘oven’ hysteria; this cell phone thing is nothing but another hysteria. It is trivial to come up with a “what if” situation to scare people; the fact remains that to make any progress we need to say “we’ve done our best and now we just have to get on and see how it works”.
There are a number of large studies that indicate just by weight of numbers that there is no effect ( Danish cancer study of 60000 for example.) Then there’s the fact that there is no mechanism for damage to cells from non ionizing radiation.
I have to point out that while the microwave oven radiation ( which is at about the upper limit of the cell phone frequency spectrum) would heat your skin from the leakage which can be as high as 1/2 watts, the ionizing radiation from the sun does too and that’s a proven cancer causer. Yet the 1000 watt microwave doesn’t seem to concern people but the 1/2 watt cell phone does.
The fact is, we sweat the small stuff and ignore the big dangers. Use your cell phone, get out of the sun after 10 minutes, you’ll be fine.
Or just use a headset.
It’s silly to rely on the null hypothesis. If I give you some unfamiliar mushroom, the null hypothesis would be that it’s harmless, but I doubt you’d eat it.
Deniers of the harm from secondhand smoke usually only focus on cancer too, and neglect heart disease, emphysema, and asthma, where the risk ratio may be greater. Much of the bias in science is not in the answers but in the choice of questions.
Ah… no, the null hypothesis for mushrooms is NOT that they are safe to eat.
1) The odds are quite likely that any random mushroom is likely to be inedible and/or harmful.
2) There is a mechanism for mushrooms and cigarettes to cause harm, alkaloids, neurotoxins, tar, cyanide, carbon monoxide. There is no mechanism for non-ionizing radiation to cause harm.
3) There is no evidence that cell phones cause harm.
I think most mushrooms are edible, yet you still wouldn’t eat a random one. But even if most were toxic, the null hypothesis could still be “no harmful effect,” not because it’s the most probable, but because we can all agree on what it means. It’s a convenient starting point. If you start by assuming it’s toxic, your idea of “toxic” may be different from mine. You could make the best current guess the null hypothesis, but then “relying on the null hypothesis” just means relying on the best current guess.
I referenced a possible mechanism and evidence of harm from non-ionizing radiation above.
Respectfully you’re all wrong :).
If given a random mushroom I wouldn’t use the Null Hypothesis. I would simply say “I don’t know”. Given that I don’t know, and some mushrooms are dangerous, I would avoid eating it.
Now, I might find some daring member of the tribe who will eat it, and then we’d find out how safe it was. After a while if he survived several sessions of eating that mushroom type, I would conclude it’s probably safe, and so I would take it slowly, maybe take a nibble one day, a bite the next, eventually I would discover that I could eat it safely.
If he was eating the mushroom for 15 years and got sick one day I wouldn’t conclude it was the mushroom ( let’s assume he knows the type and didn’t accidentally eat a death cap, fly agaric, false morel etc.) It would be prudent to assume something else made him sick.
Given a large population of people doing something ( say cell phone use), it’s inevitable that some of them are going to get sick. Now it’s easy to blame the cell phone for cancer ( though a cancer is caused by actually a variety of different causes and is in fact a variety of different diseases, so it’s a non specific label for a variety of different diseases, sort of like the “cold” ). Now since we know better, we wouldn’t blame the cell phone for X percent of the population catching a cold, or getting herpes or hemorrhoids. But since we are largely ignorant of the causes of cancer(s) it’s easy to go with “god of the gaps” reasoning and blame cell phones when some part of the population develops cancer. ( When we all know that mushrooms cause cancer !)
I withdraw my slander of the mushroom.
Ofcourse cell phone radiation can cause cancer.
That is, if one ignores the last 200 hundred years of scientific advancement, from James Clerk Maxwell onwards. Cell phone radiation damage is no more plausable than a perpetual motion machine due to the Laws of conservation of energy and momentum governing both.
We don’t only have 15 years of data to work with but hundreds of thousands of years living under constant bombardment by photons of all kinds of energy levels.If cell radiation were damaging, then the several orders of magnitude more powerful photons being emitted by the screen you’re reading this on, would be ripping your head apart right now.
The constant infra red being emitted by your own body dwarfs anything cell phones can throw at you.
LuchinG made a good point, also, where are the palm of the hand melanomas ?
But if you were to hit yourself repeatedly on the head with it or eat it, then we would have to concede that yes, cellphones could cause cancer.
Now we’re on Mount Stupid.
You have Doctors Steven Novella, David Gorski, and Harriet Hall saying that harm from cell phone radiation is not completely implausible, but you know better.
“We don’t only have 15 years of data to work with but hundreds of thousands of years living under constant bombardment by photons of all kinds of energy levels.”
First, that’s a naturalistic fallacy. After hundreds of thousands of years, sunlight still causes skin cancer and cataracts. Second, we haven’t had microwaves transmitting right at our heads, but our bodies have been emitting IR, being warm-blooded and all.
“Where are the palm of the hand melanomas?”
Has anyone even tried to find out? Probably not, because microwaves penetrate deeper than UV rays.
http://en.wikipedia.org/wiki/Microwave_burn#Skin
“Exposure to frequencies common in domestic and industrial sources rarely leads to significant skin damage… Due to the deep penetration of these frequencies, the skin may be minimally affected and show no signs of damage, while muscles, nerves, and blood vessels may be significantly damaged. Sensory nerves are particularly sensitive to such damage; cases of persistent neuritis and compression neuropathy were reported after significant microwave exposures.”
Cell phones are radio transmitter/receivers. Microwave ovens are not. The magnetron in a microwave oven operates on completely different physical principles than do the radio antenna for a cell phone. The magnetron uses the ballistic nature of electrons in a vacuum which are pulsed very rapidly whereas in a radio transmitter/receiver there is a continuous stream of electrons.
The “micro” in microwave ovens and in microwave cell phone transmissions are not of the same frequencies. “Micro” simply means smaller than ordinary radio waves which can be as long as a meter or so. It is NOT an indication of frequency.
Microwave ovens cook food through dielectric heating of organic “stuff” (a technical term ;)). They cannot cause point mutations but they do denature proteins. That’s what they’re supposed to do.
If you took a cell phone transceiver and pumped it up to 1000 watts you still couldn’t boil water with it because it’s the wrong kind of radiation. You need a magetron to do that.
Cell pones are safe.
Microwaves are a subset of radio waves between 0.3 GHz and 300 GHz.
Microwave ovens use the same frequency as cordless phones and Wi-Fi: 2.4 GHz. Cell phones use 1.9 GHz, which penetrates deeper.
A high-power microwave antenna causes burns.
The class of transmitter device in cell phones can be manufactured to function in a small region over a fairly large range of frequencies. They can be engineered to emit at the ~2.4GHz of a microwave oven but that would be senseless since the signal would be attenuated so much. The magnetron produces microwave radiation as electrons are accelerated along a helical path in a vacuum; the big deal about a magnetron is that it can be designed to produce very high power output whether continuous or in pulses.
@Max,
“The rat study I cited talks about nerve damage, not cancer…”
Sorry. I did actually follow that link; don’t know why I wrote “cancer” instead of “other adverse effects”. But, again, do you know if it’s been replicated?
Please look again at my point about replication and the convergence of evidence. If you do enough studies, looking at correlations between cell phone use or exposure to RF and various types of cancer and nerve damage and other adverse affects, you’re bound to occasionally find “statistically significant” correlations purely by chance(about 5% of the time, by definition). If these are chance correlations, you’d expect to see different, usually weak correlations in different studies, with no convergence on any specific adverse effect. You’d also expect to see occasional NEGATIVE “significant” correlations. It’s my (admittedly layman’s) understanding that this is precisely the case with studies on adverse effects of cell phone use and RF exposure (at least at the levels cell phones expose us to).
“Or just use a headset.”
But why? If cell phone use causes cancer or other adverse effects, we don’t know why. How do we know a headset (wired or not) will protect us? What if it’s the differential activation of auditory nerves in only one ear for extended periods that causes problems, not RF exposure? Or some other, total unforeseen mechanism? Again, what evidence are you aware of that using a headset reduces the risk of cell phone use?
“It’s silly to rely on the null hypothesis. If I give you some unfamiliar mushroom, the null hypothesis would be that it’s harmless, but I doubt you’d eat it.”
Except that in the case of an unfamiliar mushroom, we have strong a priori reasons to suspect that it could be dangerous. In the case of cell phones, we actually have strong a priori reasons (as Peter Damian points out above) to suspect it’s NOT dangerous. Your position appears to be more akin to refusing to eat a species of mushroom that has been widely consumed every day by much of the planet’s population for a couple of decades with no detectable adverse consequences.
“How do we know a headset (wired or not) will protect us?”
Because it’s essentially the cell phone minus everything but the speaker. It’s removing stuff, not adding stuff.
The radio transmitter is still there though, giving your head a slightly smaller dose of radiation and presumably causing abdominal or testicular cancers.
Wearing wired headphones may not be safer, that’s an assumption. The wires in the headphones can act as an antenna. You could be in fact increasing your exposure. see wikipedia tin foil hats, where rather than protecting the brain from radio sources, tin foil hats under some circumstances can amplify the radio signal to the brain.
We need an RF engineer to help with this, but my suspicion is that you’re not a lot safer with wired head phones.
Beastie Boys rapper MCA died of salivary gland cancer, which is relatively rare.
Looking up the risk factors, there are a couple of surprises.
http://www.cancer.org/Cancer/SalivaryGlandCancer/DetailedGuide/salivary-gland-cancer-risk-
“Tobacco and alcohol can increase the risk for several cancers of the head and neck area, but they have not been strongly linked to salivary gland cancers in most studies.”
“One recent study suggested an increased risk of parotid gland tumors among heavy cell phone users. In this study, most of the tumors seen were benign (not cancer). Other studies looking at this issue have not found such a link. Research in this area is still in progress. If there is any excess risk, it could be decreased by using corded or cordless earpieces that move the device away from the user’s head and decrease the amount of radiation that reaches the body.”
Fixed link
http://www.cancer.org/Cancer/SalivaryGlandCancer/DetailedGuide/salivary-gland-cancer-risk-factors
Again, we have ONE study that suggests and adverse effect – in this case an increased risk of salivary gland tumors (most of which were benign). At the same time, “Other studies looking at this issue have not found such a link.” And again, a recommendation to use an earpiece to decrease radiation exposure – with no evidence that using an earpiece significantly decreases the radiation exposure of the body part in question – with no evidence that it is radiation exposure that is causing an increased risk – which risk, according to multiple studies, doesn’t even exist.
You can cite a study that shows a correlation with neural damage in rats. Another that shows a correlation with gliomas. Another that shows a correlation with salivary tumors. And so one. But none of them seems to be replicated. Meanwhile, many more studies fail to replicate the correlations, or find any significant correlations with any adverse events. This is exactly that pattern you’d expect to find if there were no actual correlation.
Again, at the standard medical science significance level of p=.05, just by chance, you’d expect 5% of the cell phone use – adverse event correlations you look at to yield “significant” results. Add in the file drawer effect. Then add in data mining (a study finds increased risk of one particular type of cancer among the cohort of heaviest users, but no increase in other cohorts – no dose/response effect – and no replication by other studies). All together, if there were no actual adverse effects, you’d expect to find quite a few published studies finding a significant correlation, but all finding different correlations, and a repeated and consistent failure to replicate any particular correlation. Which, AFAIK, is EXACTLY what we see in the published literature on cell phone usage.
If there were a real effect, in addition to the random noise of false positives, we’d expect to see a convergence across multiple studies of similar levels of correlation between cell phone use and the SAME adverse effect(s). Exactly what we see with studies of cigarette smoking and various lung problems, and exactly what we don’t see with cell phones and…anything.
Instead of a series of one-off, un-replicated studies showing different adverse effects, can you show a convergence of evidence across multiple studies for any particular adverse effect(s)?
Dr. Novella, I mostly like this article but I have some issues with it.
You seem to leap from physicists insisting that non-ionizing radiation (NIR) cannot cause *cancer* to arguing against their supposedly saying that NIR can’t “cause health effects”. I don’t think physicists are making that assertion. As you said, heating is a well-known possible biological effect of non-ionizing radiation.
You link to one of Dr. Gorski’s blog articles in support of your argument that physicists believe NIR can’t possibly cause any harm at all (which they don’t believe). In that article, Dr. Gorski is complaining when physicists declare that NIR as a cause of cancer is “utterly impossible,” but he does go on to say that the notion is “incredibly implausible” on physics grounds (plus given the research to date).
You go on to say “More subtle biological effects are not likely but are also not completely implausible.” Is there really that much of a distinction, for all intents and purposes, between “utterly impossible” as some physicists say and “incredibly implausible” as Dr. Gorski says and “not completely implausible,” as you say? Spitting hairs, imo, when it comes to deciding to spend billions on research, and yet you call for more.
You say: “There is some local tissue warming, for example. The magnitude of this effect is very small, but it is not zero. My own feelings on the question is that biological effects from cell phone radiation is very unlikely, but it would be premature to declare them impossible. Therefore clinical research into the effects of chronic cell phone use are warranted.”
Calling for further research into anything with a higher than zero output of heat seems irrational to me. Besides, the heating effects of radiowaves/microwaves have been studied extensively (I believe tens of thousands of military and other studies), leading to current cell phone and tower or base antenna regulations. The heat from a cell phone, especially now with more efficient technology, is incredibly low, similar to holding a pen light to your head; ten cell phones might put out the same heat as a night light.
I don’t see any reason to even worry about radiation from a child using a cell phone. There are so many other things to worry about, and so many better uses for research dollars.
Damn, I should never try to write a post in the middle of the night. I made my own leap, I see. You didn’t say physicists conclude no harm from NIR, you said some scientists leap from the implausibility of NIR causing cancer to the belief that cell phones can cause no biological harm at all. Fair enough. Still, I think mostly such scientists are saying that (1) NIR cannot plausibly cause cancer, and (2) thermal effects of NIR can be a danger but the heat from cell phones is too miniscule to cause bodily harm.
thank you for such a useful information.