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Mobile phones and cancer – the full picture
An article we published last week about links between mobiles and cancer proved highly controversial. Here a cancer expert and physicist argues that it misrepresented the research and that fears are ill-founded
Last week’s article: The inconvenient truth about cancer and mobile phones
Last week the Observer published an article by Mark Hertsgaard and Mark Dowie on a disturbing topic – the idea that telecoms giants might collude to suppress evidence that wireless technology causes cancer. The feature was well written, ostensibly well researched, and deeply concerning. Its powerful narrative tapped into rich themes; our deep-seated fears about cancer, corporate greed, and technology’s potentially noxious influence on our health. It spread rapidly across social media – facilitated by the very object on which it cast doubt.
Yet as enthralling as Hertsgaard and Dowie’s narrative might be, it is strewn with rudimentary errors and dubious inferences. As a physicist working in cancer research, I found the authors’ penchant for amplifying claims far beyond that which the evidence allows troubling. And as a scientist deeply invested in public understanding of science, I’ve seen first-hand the damage that scaremongering can do to societal health. While it is tempting to rage into the void, perhaps this episode can serve as a case study in how public understanding of science can be mangled, and what warning signs we might look out for.
Cherry-picking and misrepresentation
The opening paragraph lays bare a seemingly astounding conclusion – the US’s National Toxicology Program concluded that mobile phones cause cancer. This is, to put it charitably, a devious extrapolation. The study in question observed that rats exposed to intense radiofrequency (RF) had slightly higher rates of brain cancers relative to the control group. But far from being a smoking gun, the flaws in this study paint a muddled picture. First, the preprint reveals that the rats in the RF-exposure group lived significantly longer than those controls. As cancer is primarily correlated with age, it’s not surprising the longer-lived group would get more cancer, but it would be equally daft to presume RF increases lifespan based on these results.
As other authors have pointed out , the NTP results raise several questions about methodology and interpretation but certainly do not show RF leads to cancer. Nor could a study in isolation answer this question – studies are essentially single data-points. What matters is whether consistent trends are seen across many studies. Indeed, a multitude of studies have been performed to this end, and as the World Health Organisation states , there has been no evidence of detrimental health effects: “A large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use.”
Instead of rats, we might consider human evidence. The 13-country Interphone study examined phone usage in more than 5,000 patients with brain tumours, concluding there was no causal relationship between phone use and brain tumours. And while one would expect cancer rates to increase with usage were this a cause, the dose-response curve betrayed no signs of correlation. In some instances, it registered a decrease in risk with increasing usage. Curiously, the authors are aware enough of Interphone to cite it, but utterly twist its finding by stating the study “linked wireless radiation to cancer”. This stands in stark contrast to Interphone’s actual conclusion: “Overall, no increase in risk of glioma or meningioma was observed with the use of mobile phones.”
Other studies have been similarly robust; a Danish cohort study followed 358,403 people for 27 years, again finding no link between phone usage and tumour rates. The scientific consensus to date is that there is no evidence linking cancer to mobile phones. To ignore strong evidence against a conjecture while inflating weak studies is textbook cherry-picking , where data that might contradict a particular hypothesis is jettisoned, and only evidence fitting the desired story retained. This is antithetical to science, where the totality of evidence must be assessed in concert.
Not all radiation is bad
Since the early 1990s, mobile phone usage worldwide has grown at an exponential rate. If phones are linked to cancer, we’d expect to see a marked uptick in cancer with uptake. Yet we do not. American mobile phone penetration increased from almost nothing in 1992 to practically 100% by 2008 and there is zero indication glioma rates have increased , a finding replicated by numerous other studies .
This isn’t surprising in one respect. We are surrounded by a symphony of invisible light, of which our eyes detect only a tiny sliver. The energy carried by packets of light is proportional to the frequency of that light, a finding that won Albert Einstein his Nobel prize. High-frequency light has sufficient energy to break apart chemical bonds, causing DNA damage. This is “ionising” radiation , exploited in x-ray therapy where high-energy photons are marshalled to kill tumour cells. Ionising radiation can also lead to cancer; high-energy ultraviolet radiation, for example, induces skin cancer through sustained DNA damage .
By contrast, RF (and indeed, visible light) are notoriously low energy and non-ionising, lacking the ability to wreak havoc on DNA. For cancers to form, a carcinogen needs to damage DNA – unless some extremely novel mechanism were to be discovered, it is extraordinarily unlikely that RF could cause cancer.
It’s not a conspiracy
Hertsgaard and Dowie insinuate the telecoms industry is obfuscating scientific inquiry, drawing parallels with contemptible efforts by big tobacco to negate public acceptance of the link between smoking and cancer , and attempts by fossil-fuel groups to enforce a sense of public confusion and inertia over climate change . It might not seem too much of a stretch to imply the telecoms industry would engage in similarly odious behaviour, but this reasonable edifice crumbles under even cursory reflection.
The crucial difference is that there was an abundance of strong evidence linking smoking to cancer, and for anthropogenic climate change too. Unlike RF-radiation, smoking is a clear carcinogen , linked to cancer experimentally as early as the 1920s. Subsequent experiments echoed this, showing clear causal links to cancer. By 1953, the weight of scientific evidence linking cancer to smoking was overwhelming . Similarly, climate-change is supported by evidence so strong as to be virtually incontrovertible . The scientific consensus is that our climate is changing rapidly, with the unmistakable fingerprints of human meddling making it clear we’re responsible for rising global temperatures. The mechanism behind this has long been known – French Polymath Joseph Fourier hypothesized human impact on climate in 1827 , with effects of greenhouse gases demonstrated experimentally by Irish Physicist John Tyndall in 1864.
With RF, however, the scientific evidence points to a conclusion totally at odds with what the authors postulate. The analogy to industry bamboozling the public to ignore findings doesn’t hold if there is no strong scientific consensus from which to deflect, rendering it cynical or ignorant to equivocate the twain. This is not a case of an industry trying to distract from an inescapable scientific conclusion – the reality is there is nothing of substance from which to deflect.
Shifting the burden of proof
The authors conclude by stating a “lack of definitive proof that a technology is harmful does not mean the technology is safe, yet the wireless industry has succeeded in selling this logical fallacy to the world”. Such a statement raises questions regarding their grasp of the term “logical fallacy”. The onus here is on the authors to prove their assertion – it is sheer logical contortion to present a lack of evidence as a superficial supporting argument. That the authors attribute this lack of evidence for their claims to the machinations of a nebulous big telecoms is indicative of a mindset more conspiratorial than sceptical.
The conspiratorial bent is relevant – misconceptions about wireless technology have long perpetuated. Like all the most enduring myths, fears over new technologies are built upon a tiny kernel of truth, hideously distorted. There is no shortage of websites and groups alleging all manner of damage from wifi . Disputing these narratives tends to result in personal besmirchment, with questioners labelled either a pawn of the industry or witless dupe.
While constant monitoring of an emergent technology is laudable, current evidence contradicts the hypothesis that mobile phones increase the risk of cancer. Scaremongering narratives may be more alluring than the less sensational, scientific findings, but they are not harmless. We need only look at any vaccine panic to see the cost in human life when superstition outpaces science. In an age where misinformation can perpetuate rapidly, it can be difficult to parse fact from fiction, but it’s imperative that we hone our scientific scepticism rather than succumb to baseless panics – our very wellbeing depends on it.
Dr David Robert Grimes ( @drg1985 ) is a physicist, cancer researcher, and science writer based at Queen’s University Belfast and the University of Oxford, and is also a recipient of the Sense About Science/Nature Maddox prize