I finally made time to read the results of the Interphone retrospective study on cell phones and brain cancer that were released last week. What persuaded me to do it were the radically conflicting media interpretations of the announcement. Here’s what seems to be the consensus view, as reported on the Washington Post’s “Post Tech” blog:
A large international study into the link between cellphone use and two kinds of brain cancer produced inconclusive results, according to a report to be released Tuesday in Geneva.
But researchers of the report noted flaws in the methodology of the long-awaited study. … The study’s results echo past research that the cellphone industry has cited for nearly two decades — a murky picture that there is not a conclusive link between cellphone use and cancer nor conclusive results that such a connection isn’t possible.
That’s the kind of summary I wish were written more often. Ambiguity is probably the most common scientific result, although the press seems determined not to admit it in science reporting or elsewhere. Contrast that with this take from, of all places, the BBC:
Analysis of more than 10,000 people by the International Agency for Research on Cancer (IARC) found no relationship between years of use and risk. There is no known biological mechanism by which mobiles could cause cancer, but there has been public concern. It is hoped this study will allay some anxieties, as research continues.
In other words: “You superstitious idiots only think phones cause cancer because you don’t know anything about Science.” It’s one thing to say that no link was found, but to basically insult people who believe it could exist is pretty rich. That first sentence is also carefully worded to focus on the one thing the study did rule out, instead of the many things it didn’t. Logically one would expect the amount of use to be a driver of risk rather than length of use. Why didn’t they lead with that? Because the findings about the amount of use are inconsistent, and the way the two articles deal with them is telling. One problem is that for most people there appears to be a risk-reduction associated with moderate, regular cell-phone use. Here’s the BBC’s take:
In fact, most regular users – defined as people who made use of their phone at least once a week – appeared to have a lower risk of brain cancer than those who rarely used a phone. The report authors stressed however this was unlikely to be down to any protective effect of phone use, and more a quirk of the study.
In the WaPo article this is seen as more than a mere quirk, indicative of a “flaw” and a “source of possible inaccuracies”. The other key point is that people in the highest usage category (more than 30 minutes per day) did appear to show an increased risk. Here’s how the WaPo handles that point:
The 10-year study, which was conducted by the World Health Organization’s International Agency for Research on Cancer, concluded there were “suggestions” that heavy use could increase the risk of glioma but “biases and error prevent a causal interpretation” that would directly blame cellphone radiation for the tumor.
According to the BBC story, these results were “dismissed as problematic.” The Beeb story tries pretty hard to blame this on errors in reporting, citing the fact that ten people (out of over 5000 with tumours) claimed to have spent 12 hours per day on the phone. They punch this further with a quotation from the report that the cancer “interferes with memory and cognition, undermining the accuracy of the recollections of such extreme use.” That may be true, but what it adds up to is that you don’t know if that risk is there or not. It doesn’t mean the risk should be discounted.
On the issue of funding for the study (about $24 million total), the BBC says that it “received some funding from the mobile industry”, while the Post tells us that it was “almost a quarter”. Weirdest of all is the difference on further reports. The BBC story seems to be pushing the idea that it’s a waste of taxpayer money, with this quote from the leader of the UK arm of the study:
“Whether it is worth doing more research, that is a question for society. These are expensive studies, and there are many other things in the world that should be investigated. It is society which has to answer the question of how long you continue to investigate something that does not have a biological basis.”
He has clearly made up his mind. According to the Post however, the lead researchers “urge more investigation into the topic to account for how cellphone use is affecting the health of youths” and because “the behavior of cellphone users has changed since the study was launched in 2000”. That’s a bit different. Either way, both articles report that a 30-year prospective study started last month. So 30 years from now we ought to know, although that study too is funded in part by the cell phone industry. If it gets canceled early, I might throw my phone away.