Lloyd Morgan's Column
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Commentary, Second Japanese Interphone Study1
As we will see, this Interphone study discussed here has two methodology
improvements, not previously seen in published Interphone brain tumor studies.
The two improvements are:
- Looking at three categories of Specific Absorption Rate (SAR)2 exposure within the brain tumor.
However, one table (Table 2), for various indices of cellphone
use, reports results for glioma,3 meningioma,
4 and pituitary adenoma.5 This table considered all tumors as exposed. It is not clear
why tumors of the pituitary gland were investigated, for as the study
states, "[P]ituitary adenomas occur [at the base of the skull], where RF
exposure is negligible..." As a result, this study, while introducing two
improvements not previous seen in Interphone studies, makes only a partial
improvement in one.
- Control subjects eligible for participation were not told their
participation would be for a cellphone study.
A cellphone's radiation plume penetrates a small volume of the brain. Thus,
tumors outside the plume are unexposed tumors. Treating all brain tumors, as in
Table 2, as exposed, results in an underestimation of the risk of brain tumors.
This second Japanese Interphone study examines the power absorbed within
gliomas and meningiomas (SAR). Previously, no Interphone brain tumor study
examined the power absorbed within the brain tumor. This study presents results
for three categories of power absorption within the brain. Though hampered by
design flaws that underestimate the risk, a 5.84-fold risk of glioma was found
[see Results, Risk of Glioma (Brain Cancer)].
Determining the power absorbed at the site of a brain tumor is essential.
Yet, even though this study does look at tumors within the radiation plume
(Tables 3, and 4), because of other design flaws, it is almost incapable of
finding a risk.
Five of these six design flaws independently underestimate the risk of brain
tumors. Three of the flaws are resolved in this study. For a thorough
examination of these design flaws see Interphone Studies to Date, An Examination of Poor Study Design, Resulting in
an Underestimation of the Risk of Brain Tumors.
When potential controls are asked to participate in a cellphone study, it is
reasonable to assume that potential controls using a cellphone are more likely
to agree to participate compared to potential controls that are not using a
cellphone. The result is a problem called selection bias. Selection bias will
underestimate the risk of brain tumors. Not telling potential controls,
recruited to participate in this study, it is a cellphone study, eliminates
1 - Takebayashi et al. Mobile phone use,
exposure to radiofrequency electromagnetic field, and brain tumour: a
case-control study. British Journal of Cancer (2008) 98, 652 - 659.
2 - SAR is the amount of energy absorbed is
tissue, in this case brain tissue, from cellphone radiation. SAR is measured in
Watts per kilogram of tissue.
3 - A glioma is a tumor of the glial cells in the
brain. Colloquially it is referred to as brain cancer.
4 - A meningioma is a tumor of the meninges that
surround the brain and spinal cord.
5 - The pituitary (master) gland is located at
the skull base.
Six Interphone Protocol Design Flaws and Limitations of this Study
Flaw 1: Selection Bias
This flaw is resolved in the third improvement.
Flaw 2: Inclusion of Tumors Outside the Cellphone's Radiation Plume
This flaw is resolved in the first and second improvement.
Flaw 3: Latency Time and Definition of Regular User
This flaw results in an underestimation of risk and is not resolved in this
study (see The limitations of this study below). It is a major contributor to
the underestimation of risk. Thus, this flaw alone, is why it is nearly
impossible to find a risk of brain tumors.
Latency Time: Latency time is the time from exposure to diagnosis.
Data from ionizing radiation, reports brain tumor latency time is between 20 and
40 years (similar to smoking and lung cancer). With only 2 cases (2.4% of all
cases) at 10+ years, there is virtually no possibility of finding a risk for
10+ years of use.
Of particular interest is that the number of cases (8) in the first
Takebayashi study was 2.4% of all cases, identical to the this Takebayashi
Definition of Regular User: The Internet Protocol defines regular
cellphone use as use for at least once a week, for 6 months or more with
diagnosis at least a year previous. Given the rapid adoption of cellphone
everywhere, the vast percentage of cellphone users have used a cellphone for far
too short of time for any reasonable brain tumor latency time.
Flaw 4: Children and Young Adults Are Not Included in the Interphone
Children, due to their rapid cell growth, are far more at risk to a tumorgenic
exposure than adults. The range of age in this study was 30 to 59. Not having
younger subjects in the study results in an underestimation of risk.
Flaw 4 results in an underestimation of risk and is not resolved in this
Flaw 5: Cellphone's Radiated Power
This flaw is resolve by the inclusion of various SAR metrics.
Flaw 6: Number of Cases Included in a Study
This study has far too few cases, considering the latency time for a tumor to
be diagnosed. In total it has 83 glioma cases and 128 meningioma cases. The
result: only 2 glioma cases and only 4 meningioma cases had used a cellphone for
10+ years. This study required far more cases (at least 15 times more glioma
cases) in order to have meaningful results for a 10+ year brain tumor latency
Results: Risk of Glioma (AKA Brain Cancer)
At the beginning of the Discussion section this study states, "No consistent
increase [in risk] was observed in the overall risk of glioma or meningioma
among mobile phone users ..." The authors are using "consistent" to hide the
important results of this study. There are three important results: one is
alarming, two raise concerns.
For the highest compared to the lowest Cumulative maxSAR-hours (> 10, or
> 1,000 hours of use) there was a 5.84-fold risk of glioma. The text comments
that the finding was not significant (< 95% confidence). It is outrageous
that this finding was described a non-significant without further qualification!
The nearly 6-fold risk of brain cancer has a confidence level of 94.9% (7
For the "mid-high" category of mean maxSAR6,
the risk of glioma (15 cases) was 2.98-fold and was a tad lower than 95%
confidence. For mean maxSAR with values between 0.001 and 0.01 Watts per
kilogram the risk of glioma was 2.30-fold and the confidence was 91% (17 cases).
These findings are a reason enough to be concerned about using a cellphone.
While this study made two improvements, the existing flaws, particularly the
short latency time, made it nearly impossible to find a risk. Because the study
did find risks, it should result in a world-wide set of public health actions
to substantially reduce the absorbed cellphone radiation. For example, the
consistent use of a wired headset and not allowing children to use cellphones.
The 5.84-fold glioma risk found for > 1,000 hours (2 cases) of use it
confirms the Hardell team's findings of a 1.3-fold risk, for < 1,000 hours
(355 cases), a 1.8-fold risk for 1,001 to 2,000 hour (26 cases), and a 3.7-fold
risk for > 2,000 hours (21 cases)7. However,
this study found a much higher risk than the Hardell study. Suggesting, because
the > 1,000 hours was > 1,000 hours at the highest value for mean maxSAR,
that higher SAR values create higher risk.
Bottom line: in spite of the BBC's headline "Mobiles 'not brain cancer
risk'", the risk of brain tumors from cellphone use exists.
6 - Mean maxSAR is the average maximum for all
the phones used by a subject.
7 - Hardell et al, Pooled analysis of two
case-control studies on use of cellular and cordless telephones and the risk for
malignant brain tumours diagnosed in 1997-2003. Int Arch Occup Environ Health.
2006 Sep;79(8):630-9. Epub 2006 Mar 16.