Friday, June 25, 2010
An opportunity to explain one of the simplest and most powerful concepts of
science to the public is slipping away. A month ago WHO released its long-
awaited Interphone study of cell phones and brain cancer in 13 countries.
The 10 year, $14 million, case-control study reports that "no increase in
risk of glioma or meningioma was observed with the use of mobile phones."
That's the right answer, so why am I pissed? We already knew that cell
phones don't cause cancer. We've known it for years. From the media
coverage you would think these guys just discovered it. Let's go to the
next sentence: "There were suggestions of an increased risk of glioma at
higher exposure levels, but biases and error prevented a causal
interpretation." So is there a supernatural interpretation? That one
sentence undoes everything in the study. Case-control requires human
recollection; at their best case-control studies are to science as polls
are to elections. They may come out the same, but you can't count on it.
Ten years ago a group in Denmark published a beautiful epidemiological
study of cell phones and brain cancer in the Journal of the National Cancer
Institute: Johansen C.Boice JD Jr, McLaughlin JK, Olsen JH. Cellular
telephones and cancer a nationwide Cohort study in Denmark. J Natl
Cancer Inst 2001;93:2037. The study was based entirely on existing
public records: the Danish Cancer Registry, mobile phone charges, death
records, subscriptions, etc. The conclusion was unequivocal: There was no
correlation between cell phone use and the incidence of brain cancer. It
was nice to have that fact confirmed, but it was not a surprise. I was
invited to write an editorial on how scientists should respond to the cell
phone/brain cancer question, for the same issue of JNCI JNCI, Vol. 93, No.
3, 166-167, February 7, 2001. Cancer agents act by creating mutant strands
of DNA. In the case of electromagnetic radiation, there is a sharp
threshold for this process at the extreme blue end of the visible
spectrum. Albert Einstein explained this with the photoelectric effect in
1905, for which he received the Nobel Prize in 1921. Cell phones operate
at a frequency about 1 million times lower than the ultraviolet threshold
and hence cannot be a cause of cancer. It's important to recognize that
it's not the intensity of radiation that makes it a cancer agent, but the
frequency.
They can if you disable the interlock on your microwave oven and stick your
head in it, but your cell phone operates on tiny little batteries. They
don't have much power. How hot does your hand get holding your microwave?
Your body uses blood as a coolant to maintain a pretty constant temperature
over the body parts. Especially the brain. It's got its work cut out for
it today in Washington.
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