12/28/10

Maybe cell phones do maraud a little bit, but so what?

Now, instead of thinking that the concern for cancer risk from cell phones is BS, I think the concerns are exaggerated and misplaced. Let me explain.

When I wrote my previous post, I was not aware of the meta-analysis from 2009 by Myung et al. in the Journal of Clinical Oncology. (A meta-analysis uses statistical techniques to classify and then pool results from a number of studies.) The work by Myung et al. needs some detailed discussion, but it presents some findings which bear consideration: first, that in the subgroup of studies they considered which were of higher quality, there is a positive association between any cell-phone use (compared to rare or never use) and brain tumors both benign and malignant. Second, there is a significant association, in all studies which consider cell-phone use of 10 years or longer, between that length of use and brain tumors.

There are some caveats here. First, the "high-quality studies" are all chips off one larger study, i.e. done by the same group of researchers - and the lower-quality studies are all from another larger study. This means that there haven't been too many separate groups studying this topic recently in a scientifically legitimate way. Second, all the studies considered in this meta-analysis (23 of them) are case-control studies, which for various reasons are often considered more susceptible to bias than cohort studies, in which groups of subjects are followed for the development of brain tumors. Thus the biases I talked about in my previous post still apply.

Since the associations are small, susceptible to bias, and only in a subgroup of available studies, I would say the jury is still out.

Even when the jury comes back from sequestration (cell phones turned off, I guess), my general impression from my previous post holds true. I would not make any individual change in lifestyle, much less any public policy decisions, based on these weak-if-true associations, just because there are so many things in this world (even confining ourselves to our individual and public health) which are more important to worry about.

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