French study raises questions on mobile phone safety

by Elisabeth Zingg
Credit: Vojko Kalan/public domain

People who use mobile phones intensively appear to have a higher risk of developing certain types of brain cancer, French scientists said on Tuesday, reviving questions about phone safety.

Individuals who used their cellphone for more than 15 hours each month over five years on average had between two and three times greater risk of developing glioma and meningioma tumours compared with people whose used their phone rarely, they found.

The study, appearing in the latest issue of British journal Occupational and Environmental Medicine, is the latest foray in a long-running exploration of safety.

Over the last 15 years, most investigations have failed to turn up conclusive results either way, although several have suggested a link between gliomas and intensive, long-term use.

"Our study is part of that trend, but the results have to be confirmed," said Isabelle Baldi, of the University of Bordeaux in southwestern France, who took part in the probe.

In 2011, the International Agency for Research on Cancer (IARC) said radiofrequency fields used by mobile phones are possibly carcinogenic.

But research faces several challenges. They include clear proof in the lab that these fields are harmful to human cells.

Another is getting an accurate picture of phone use in real life, filtering out lifestyle factors such as smoking which amplify cancer risk and taking into account changing phone technology.

The new study looked at 253 cases of glioma and 194 cases of meningioma reported in four French departments (counties) between 2004 and 2006.

These patients were matched against 892 "controls," or healthy individuals drawn from the general population, in a bid to spot any differences between the two groups.

The comparison found a higher risk among those who used their phone intensively, especially among those who used it for their work, such as in sales. The duration of use in this category ranged from between two and 10 years, averaging at five years.

But study also found several inconsistencies with other investigations that have suggested a link between heavy phone use and .

For instance, in contrast with previous work, it found that occurred on the opposite side of the brain, rather than on the same side, of where the phone was customarily used.

"It is difficult to define a level of risk, if any, especially as is constantly evolving," the study acknowledged.

"The rapid evolution of technology has led to a considerable increase in the use of mobile phones and a parallel decrease of [radiowave intensity] emitted by the phones.

"Studies taking account of these recent developments and allowing the observation of potential long-term effects will be needed."

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verkle
1 / 5 (4) May 13, 2014
Just like the Fukushima nuclear power plant disaster, radiation effects won't be seen for years after. And then it might be too late.
Eikka
4.7 / 5 (3) May 13, 2014
Just like the Fukushima nuclear power plant disaster, radiation effects won't be seen for years after.


Problem is, there is no plausible mechanism by which microwaves can affect human cells, except by direct heating at unplausibly high power.

These studies are a textbook example of faulty statistics, because they either look at small sample sizes, or find correlations with large numbers of potential causes.

If you take cancer patients and try to see what they are doing differently than your "average" person, you're looking at hundreds of things that are individually improbable, but taken collectively finding at least one correlate is very probable.

There's also confirmation bias: if the study showed e.g. that bicycling is causing brain cancer, they either don't publish, or they pick the next weaker correlate which just happens to be cellphones.

The fact that they found correlation with cancer on the opposite side of the brain is a good indication that the result is false.
Eikka
5 / 5 (2) May 13, 2014
-the- textbook example of this kind of bad statistics is the power lines vs. leukemia scare of a while back. Basically, they assumed that power lines -are- causing some sort of illness and tried to find out what it was, so they took a number of people who are living near powerlines and compared them to a list of some 800 different ailments.

Again, individually the probability that any one of those would be present is very small, but when you add up 800 small probabilities you get a large probability that somehow a great number of people suffering from any one of those ailments have found their way into your sample of people by pure chance.

So they found that they had an unusually large number of people with leukemia and called it a day: "power lines are causing leukemia".

Except later studies took a larger sample of people diagnosed with leukemia within a country, hundreds of thousands of them, and the correlation vanished. They didn't live near power lines more than anyone else.
Eikka
4.7 / 5 (3) May 13, 2014
Plus, there is an open question in their sampling method:

The new study looked at 253 cases of glioma and 194 cases of meningioma reported in four French departments (counties) between 2004 and 2006.

These patients were matched against 892 "controls," or healthy individuals drawn from the general population


Suppose these specific types of brain cancer are more prevalent in urban rather than sub-urban and rural populations for reasons specific to the urban environment such as air pollution. It is known that this is the case for cancers in general.

At the same time, urban populations are heavier cellphone users.

So you have more urban brain cancer sufferers who use more cellphones, and you compare them against the "general population" who on average aren't exposed to cellphones as much, and you will find that cellphones correlate with brain cancer.

In this way you can find a correlation to cancer with any arbitrary activity that city dwellers do more than country folk.
Krewger
3 / 5 (1) May 13, 2014
It's an interesting study but I would also ask how long have we been closely monitoring these types of brain cancer? Realistically I think we forget that in 1900 we were running around on horse and buggy instead of driving cars and Ford released the Model T in 1908. Our understanding of medicine, cancers and how diseases and disorders have just recently been placed under scrutiny at a level never before possible with our modern technology compared to the the last 20,000 years of humans inhabiting the earth. We are finally establishing baselines and databases that were only truly possible with computers to comprehend the data we were looking at and that has only been in the last 15-20 years that we have begun digitizing medical records in the capacity of being able to properly aggregate results from big data. These cancers might be more prevalent than before thought and environmental impact such as work stress could also play a part in this that is not yet well documented.
Eikka
not rated yet May 20, 2014
These cancers might be more prevalent than before thought and environmental impact such as work stress could also play a part in this that is not yet well documented.


I think I remember there's at least some evidence that breast cancers are caused as much by stress as other physical factors, with people living in bad neighborhoods and in poverty being at increased risk.