How reliable is the epidemiological evidence on mobile phones and cancer?
Friday, July 24, 2009
Comments by Cindy Sage on 3rd Blog - Between a Rock and A Hard Place Blog
Dariusz,
Several questions and comments:
1) You say Auvinen profiled ‘all published epidemiological studies to date dealing with mobile phones and cancer’ at the BEMS meeting. Did he include the Kan et al., (2007) meta-analysis? For brain tumors, it reported a pooled OR for long-term users of 10 years and longer (5 studies) at 1.25 (CI = 1.01-1.54). This is important. The meta-analsis EXCLUDED any Hardell et al studies. It still found increased risk of brain tumor. J Neurooncol. 2007 July 1:(Epub). Kan P Simonsen SE Lyon JL Kestle JR. Division of Pediatric Neurosurgery, Department of Neurosurgery, University of Utah, 100 N. Medical Drive, Salt Lake City, Utah. john.kestle@hsc.utah.edu
2) You say Auvinen indicated “the scientific evidence is of insufficient quality to reliably draw any health-risk-related estimates.” Well, this cannot be true when all the published studies to date with data on 10 year and longer latency report increased risk of malignant brain tumor. It is enough to say there is early evidence of some risk, but the risk cannot yet be quantified precisely. So, it is sufficient for early precautionary advice. That should be the signal from the evidence to date.
3) By agreeing with Auvinen’s position that “more case-control studies will not improve the situation because of unavoidable biases, and will only be a waste of time and money”, are you saying that Hardell et al studies are a waste? That they contribute no useful information?
4) You say that “case-control studies” are of such insufficient quality hat drawing any health-related conclusions is like ‘flipping-a-coin”. In fact, you could and should say also that cohort studies suffer from the same methodological deficiencies and are equally or more unreliable. There are several published articles reporting the specific deficiencies of other types of epidemiological studies, including exclusion of heavy users, diluting effects by including improper definition of regular user, drawing conclusions from latency periods too short to show effects and finding none, concluding there is no risk, etc. Deficiencies that have led to ORs consistently under 1 across many of the published studies indicate omething is wrong with their research design, or execution.
5) I think the results of the paper in Epidemiology and the ICNIRP RF Review paper do have consistent conclusions (you do not). ICNIRP concludes that “Results of epidemiological studies to date give no consistent or convincing evidence of a causal relationship between RF exposure and any adverse health effect. On the other hand, these studies have too many deficiencies to rule out an association.” A conclusion of the Epidemiology paper is “For slow-growing tumors such as meningioma and acoustic neuroma, as well as glioma among long-term users, the absence of an association reported thus far is inconclusive because the observation period has been too short.” It cannot rule out effects either. And because the Epidemiology paper omits reference to the Kan et al., 2007 finding of increased risk at 10 or more years, excluding all the Hardell et al papers, and because it dismisses its own finding that combined results of studies with 10 years or more of cell phone use show elevated risks as ‘deviant results’, fixing these two glaring errors would perhaps require a shift to “there is some evidence” or “there is a real risk”.
6) You conclude that “at this time, any statements suggesting that ‘there is a health risk’ or ‘there is no health risk’, based on the epidemiological evidence, are premature and not reliabily supported by the available science.” Dariusz, you forget that it is not black and white, nor are we given only two choices - yes it does, or no it does not conclusively cause brain tumors. There is the important middle ground which would say “we have some evidence… and that the risks of doing nothing with it, of waiting until we know definitively one way or the other, will result in decades of unnecessary exposures that could have been prevented by some sensible public health cautions based on the data showing some risk at 10 years or longer use. There is no excuse for demanding an ‘either or” scenario. Thanks for the forum to discuss these ideas. You are doing us all a service by providing a place for exchange of viewpoints
Cindy Sage
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CINDY SAGE COMMENTS ON DARIUSZ LESZCZYNSKI’S BLOG
Source: EMFacts
Date: 07/24/2009
