1. The study by Aydin et al. contradicts its own conclusion that there is no exposure-response relationship between mobile phone use and brain tumors in children. Their data shows a clear exposure-response relationship. 2. The study contains multiple data discrepancies between the numbers reported in the text and tables. These discrepancies call into question the results and conclusions. 3. Over 60% of brain tumor locations in the study were reported as unknown or central, and these cases all showed protective effects, suggesting a methodological problem.

1. 1
Correspondence
Re: Mobile Phone Use and Brain Tumors in Children and Adolescents: A
Multicenter Case–Control Study
Aydin et al. (1)’s data contradicts its conclusion, has multiple data discrepancies and
methodological problems in their laterality analysis.
Contradiction
They conclude, “The absence of an exposure–response relationship either in terms of the
amount of mobile phone use …,” yet report, 2.8 years after the first subscription for a cellphone
began, using operator data, OR=2.15, 95% CI=1.07 to 4.29, combined with Ptrend=0.001,
indicating a clear exposure-response relationship.
The results also suggest that children and adolescents may have a shorter latency time for the
development of brain cancer than adults.
Data Discrepancies
Both Tables 4 and 5 have three mutually exclusive categories. The total cases from these 3
categories are 671 and 613 respectively in a study with 352 cases.
The authors report 423 eligible cases and 909 eligible controls, with participation by 352
cases (83.2%) and 646 controls (71.0%) resulting in exclusion of 71 cases and 263 controls.
When the reasons for exclusion are summed, there were 121 cases (50 additional), 280 controls
(17 additional). This would result in case participation of 60% and control participation of 69%,
which in turn would likely increase various biases.
The text reports that 35% of cases and 34% of controls had operator data. If this was true
then there would be 123 cases and 200 controls. Table 4 reports 196 cases and 360 controls
with operator data. The reason for this discrepancy is unclear, but it would likely make a large
difference in the associated risks as there would be 37% fewer cases and 39% fewer controls.
Methodological Problems
Table 5 reported 215 cases (61%) that had either an unknown location or were centrally
located, with no explanation why the locations were unknown. Perhaps this explains why all 13
risks in this category were protective, 3 significantly, and all 4 trends found increasing protection
with increasing exposure.
Twelve of the thirteen laterality results indicated higher contralateral risks than ipsilateral.
However, their definitions of ipsilateral and contralateral use differ from dictionary definitions,
and from those employed in all previous cellphone studies. Many other studies have found a
clear association between side of head on which phone use was generally reported and location
of brain tumor association (2-4). In any event, results reported an increased risk, with 7 of 8
trends for increasing risk with increasing exposure being significant or borderline significant
(Ptrend<0.10). Significant risks ranged from 2.66 to 6.19. Risks of this magnitude for childhood
brain cancer, combined with increasing risk with increasing exposure, are alarming.
Financial Bias and Summary
Several cellphone companies provided funding for this study. The problem of financial bias
has been well documented (5-7). Conspicuously missing from the Funding and Notes section are

2. 2
individual conflicts of interests among the authors (e.g., consulting, stock ownership, director
status, etc.).
The numerous discrepancies suggest a poor peer-review process and/or a rush to publish.
Despite the discrepancies in the report, their data support the relationship between exposure
and increased risk for brain tumors.
L. Lloyd Morgan, BS
Ronald B Herberman, MD
Devra Lee Davis, PhD
Notes
Affiliations of authors: Environmental Heath Trust; Intrexon Corporation; Environmental Health Trust
Correspondence to: L. Lloyd Morgan, 2022 Francisco Street, Berkeley, CA 94709, USA (email:
Lloyd.L.Morgan@gmail.com).
References
1. Aydin D, Feychting M, Schüz J, Tynes T, Andersen TV, Schmidt LS, Poulsen AH,
Johansen C, Prochazka M, Lannering B, Klaeboe L, Eggen T, Jenni D, Grotzer M,
Von der Weid N, Kuehn C, Röösli M. Mobile Phone Use and Brain Tumors in
Children and Adolescents: A Multicenter Case–Control Study. J Natl Cancer Inst.
2011;103:1–13.
2. Löon S, Ahlbom A, Hall P, Feychting M. Mobile Phone Use and the Risk of
Acoustic Neuroma. Epidemiology 2004;15: 653–659.
3. Hardell L, Carlberg M, Hansson Mild K, Pooled analysis of two case-control
studies on the use of cellular and cordless telephones and the risk of benign brain
tumours diagnosed during 1997-2003. Int J OF Oncol 28: 509-518, 2006.
4. Hardell L, Carlberg M. Mobile phones, cordless phones and the risk for brain
tumours. Int. J Oncol 35: 5-17, 2009.
5. Morgan LL. Estimating the risk of brain tumors from cellphone use: Published
case-control studies. Pathophysiology. 2009 Aug;16(2-3):137-47. Epub 2009 Apr
7.
6. Huss, et al., Source of funding and results of studies of health effects of mobile
phone use: systematic review of experimental studies, Environ. Health Perspect.
115 (2007) 1–4.
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