Saturday, June 4, 2011

Phones of doom?

Bonus post on cell phones ... a pet peeve.

I don't own a cell phone. Nevertheless, as a scientist, the discussion of cell phone dangers intrigues me to no end. The topic was brought up breathlessly by some neighbors a few years ago, with anecdotes about a rash of coworkers who had come down with brain tumors. I replied that the physics simply didn't merit any concern at all. Now the WHO has flagged cell phones as "possible" carcinogens, putting them in the same class as virtually every other substance on earth ... it is not a very meaningful designation, really.

The radiation we are talking about here is a thousand-fold less powerful, per photon, than visible light. And while UV light beyond the upper end of the visible range can damage our skin, break chemical bonds, and cause cancer, the much less powerful photons of radio waves can't do anything of the sort. At most, they might induce a little bit of jiggling of our molecules- some extra heat beyond that naturally flowing through our veins. It is the high-energy ionizing radiation that we need to worry about- the kind we get from CAT scans, mammograms, radon, living & flying at high altitudes, and from breathing in the exhaust of coal plants, among many other things.

For me, it comes down to data, and these graphs say it all:

First, the adoption of cell phones.

Second, the incidence of brain tumors (data from Minnesota).

You can see that so far into the cell phone epidemic, there has been no correlated cancer epidemic of the brain (or anything else). One might claim that it could take decades for such cancers to develop. In that case, the anecdotal evidence of cancer clusters is contradictory and worthless. Even if the average gestation time is long, a serious cancer risk will cause early cases as well, since some part of the population is already older and predisposed to be pushed over the edge by this new carcinogenic insult. The cases would already be showing up at some detectible rate.

What this is really about is magical thinking, as people wonder at "waves" going through them, feel instinctively violated, and fall prey to archetypal fears. This extends to researchers as well, who routinely, especially in social and medical sciences, get the results they expect from studies which, when replicated, show lower and lower effect sizes with each replication. Our unconscious exerts strong effects on everything we do, and it is the premiere accomplishment of the scientific method to, at times when we want accurate data, find ways to cordon off reality and the hypothesis at issue from all the other biasses we can subtly bring to bear on such a question. Yet this is easier said than done.

So don't worry. And while science keeps on going and may yet find that cell phones pose some measurable risk, the epidemiology already tells that the risk is certain to be vanishingly small- much less than the chance of dying from driving while using a cell phone.

1 comment:

  1. Burk - thanks for this. Cancer is, for the most part, more a symptom of old age than it is anything else... we simply live long enough now for cancers to form. Of course cancer is terrible and we should fund research to find ways to treat and eliminate it. But to add things to the list of carcinogens seems pointless, as you say.
    I had a joke poster once that read: "WARNING: The Surgeon General has determined that doing anything, anytime, anywhere with anyone may be hazardous to your health. Have a nice day." Indeed.