Here we go again. As you may have already discerned from the panicky headlines exploding across your feed – “Cellphone-Cancer Link Found in Government Study,” “Major Cell Phone Radiation Study Reignites Cancer Questions,” and so on – new data were just released which suggest a link between cell phone use and cancer.Well, in rats. But only male ones. And the group of rats those rats were compared to seemed weirdly immune to the cancers in question. Also, the male rats exposed to the cell-phone radiation lived longer than the ones who weren’t. Also also, the cell-phone-radiation rats only got the cancers in question at the rates they were supposed to, given the previously observed prevalence of these cancers in rats.
Has your heart rate slowed yet? Good. This sort of unnecessary panic is what happens in the age of hypercompetitive social-media science journalism, and it sucks.
As Megan Thielking and Dylan Scott of STAT News report, the big, $25-million study, some of the results of which were released late last night, was conducted by the U.S. National Toxicology Program. To oversimplify a bit, it involved dosing a bunch of rats with what researchers believe to be levels of cell-phone radiation equivalent to what humans are hit with when they use cell phones, and then comparing their health outcomes to a control group that wasn’t exposed to the radiation.
The headline finding, as STAT puts it, is that the rats who used adorable miniature cell phones — I know that’s not really how the study was conducted, but I can’t get that image out of my head — experienced “higher incidence of two types of cancer: malignant gliomas in the brain and schwannomas in the heart” than the control group asked to turn their rodent-phones in to the researchers for the duration of the study (sorry).
Then STAT lays out what it describes as “major caveats”:
The statistically significant results were limited to male rats. … The male rats exposed to radiation — about 9 hours a day, 7 days a week — also lived longer than a control group not exposed to radiation. In addition, it was unusual that no cancers occurred in the control group in this study. The incidence of malignant gliomas in male rats exposed to radiation — 2.2 percent to 3.3 percent — was within the range seen in non-exposed rats in previous studies, the authors said …
In a very good post at The Incidental Economist, Aaron Carroll also highlights a bunch of caveats, some overlapping with the ones mentioned by Thielking and Scott, others more technical. He also notes that some of the basic statistical information you’d expect to see in published research is absent here, making it hard to fully evaluate the findings.
So let’s cut to the chase: Should you be worried about cell-phone use based on this study? I’d argue you shouldn’t be. Based on STAT’s explanation, after all, the rats in the cell-phone-radiation group got these cancers at the rates they were supposed to. There’s only an “increased risk” in the sense that male rats in the radiation group were more likely to get cancer than a group of rats who seemed strangely resistant to cancer. It sounds as though if the control group had developed these cancers at the normal levels, there wouldn’t have been much to report here at all. And still, those male rats lived longer anyway!
To be sure, the weirdness of this study does not mean it’s impossible that cell phones are legitimately dangerous. One study can neither overturn the consensus(ish) that cell phones are safe — STAT notes that while the World Health Organization classifies cell phones as a possible carcinogen, the organization places them in the same category “given to coffee and talcum powder” — nor confirm it in a dispositive manner.
But science isn’t a buffet: You can’t wander around a given study’s statistically significant findings, scooping only those which tell a compelling story onto your plate (rich mac and cheese) while ignoring those which complicate things or point in the opposite direction (brussels sprouts). If you’re going to insist that a study tells a story people should care about, the whole thing has to make sense — it has to be prix fixe coherent.
In this case, for example, why would there be gender differences? I am no expert on rat physiology (maybe I’ll head in that direction if journalism doesn’t work out), but it strikes me as quite unlikely that the hearts and brains of he-rats and she-rats differ enough that one is immune to the carcinogenic effects of cell-phone radiation and the other is susceptible to it. You can’t leave that gender difference steaming, untouched, in the tray! If you’re going to tell a story about cell-phone cancer risk, it has to incorporate both the mac and cheese and the health food, too. Because by buffet logic, outlets could just as easily post headlines like “Women May Be Immune to Cell-Phone Radiation, Suggests Rat Study,” or “Cell Phones May Make People Live Longer, Suggests Rat Study.”
“The researchers have more data stockpiled that they haven’t reported,” reports STAT. “They say the rest of the results from the study will likely trickle out starting in late 2017.” Maybe that will clarify things. Maybe, in the long run, this will be the study that proves we are all slowly killing ourselves with cell-phone use (though it’s worth noting that fewer and fewer people are holding cell phones up to their heads these days, which might affect questions of dangerousness). But in the meantime, don’t fall for the headlines. Science isn’t a buffet!