19/01/2006 - New Glioma research incorrectly dismisses Mobile Phone Usage
New Mobile Phone Use and Glioma paper
Hepworth SJ, et al, Mobile phone use and risk of glioma in adults: case-control
study
BMJ Online First, 20th January 2006
This paper and its accompanying Press Release make the following claim
without appropriate justification: "Use of a mobile phone, either in the
short or medium term, is not associated with an increased risk of glioma."
(Abstract Conclusions)
It is Powerwatch's view that this is a highly misleading claim, either
through a deliberate and politically motivated attempt to spin the information
towards a set goal, or due to incompetent assessment of the results in the
report.
The study does, indeed, find that result for the gliomas studied - but the
sample used excluded a large majority of the high grade (fast growing) glioma
cases because: "We interviewed 51% of those patients with glioma who were
eligible, mainly because rapid death prevented us from approaching all of
them." (Discussion - Potential Bias, Paragraph 1)
They continue: "As early death is most likely in patients with high grade
tumours, it is not surprising that participation rates were higher in those with
low grade tumours. A bias in these results would occur only if mobile phone use
was related to severity of tumour, which was not supported by our analysis,
where odds ratios for mobile phone use showed no increased risk for high or low
grade tumours." It is equally misleading here to state "which was not
supported by our analysis" when they do not in fact present any analysis for
mobile phone usage differences between the cases with low-grade and high-grade
gliomas. Also, although they admit to not having a representative number of
high-grade gliomas, they do not provide any case numbers for the two groups.
Once again, this can only be due to either an ulterior motive or incompetence,
as the only reasonable conclusion in this respect would be to say "due to the
small number of high grade cases in our study, we cannot assess the effect of
mobile phone usage on high grade gliomas".
Simplistically, in middle-age adults, about 50% of gliomas are low grade and
50% are high grade. Most high grade gliomas are fast growing and fatal within a
few years. As they only included 51% of possible cases, and admit that there was
a strong bias (chi2 p=0.001) towards low grade tumours, then we are
left to assume that they had, in fact, very few high grade glioma cases. In
which case, this is further evidence that they have no scientific justification
for commenting on either high grade gliomas or gliomas as a whole. Without
research to suggest otherwise, it is perfectly plausible to suggest that mobile
phone usage may have a large impact on high grade glioma cases that were in the
49% of cases omitted.
It is very disappointing that these well-respected scientists can draw such
badly justified conclusions from their research. Had this study limited its
conclusions to the results found from the available cases, and commented that no
conclusions can be drawn about the cause of approximately half of all gliomas,
the study would have been fine. As it is, it presents a highly misleading
overall picture, and may make it harder to get funding to look into causes of
high grade gliomas, about which there is still little known. One can only hope
that the conclusions are down to an incompetent misrepresentation as opposed to
a more sinister motivation.
As high grade gliomas seem to be fatal within a short time of diagnosis, it
is clear that a prospective study is now needed that will record details of
cases as they are diagnosed.
Alasdair Philips
Director of Powerwatch
| 
