Page 35 - Contributed Paper Session (CPS) - Volume 6

CPS1483 Ken Karipidis et. al

There were increasing trends for all locations and a strong decreasing trend
for unspecified location during the period of increased CT and MRI use (1982-
1992) Table 1. There were also increases in the frontal and temporal lobes and
a smaller decrease in unspecified location during the period of advances in
MRI (1993-2002); this period also had a very large decrease in gliomas with
overlapping location. During the period of substantial mobile use there were
no increases in any of the locations apart from the frontal lobe and there was
a strong decrease in unspecified location. With the redistribution of a high
number of gliomas with unspecified and overlapping location there was a
much lower increasing trend only for gliomas in the frontal lobe during all
three periods and a large increase in the parietal lobe during the first period
(Table 2).
Predicted Incidence: Assuming a causal association between mobile phone
use and glioma, the predicted incidence trends for both genders during 2003-
2013 by applying various relative risks, latency periods and mobile phone use
scenarios are shown in Table 3. The predicted incidence trends showed an
increase for most mobile phone use scenarios and latency periods that were
modelled apart from a 20-year latency period. The highest expected trends
were generally seen for a 10-year latency period, which was the latency period
associated with mobile phones and brain tumour as reported in the
Interphone and Swedish studies.
With a RR of 2 for all mobile phone users and a latency of 10 years, the
predicted incidence rate for both genders in 2013 was 7.3 per 100,000 people
(6.7 to 7.9) compared to the observed 4.5 per 100,000. The predicted rates
increase to 8.7 (8.1 to 9.3) and 10.2 (9.5 to 10.8) per 100,000 for RRs of 2.5 and
3 respectively. With a RR of 1.5 for regular users and a RR of 2 for heavy users
and a latency of 10 years the predicted rate was 6.1 per 100,000 (5.6 to 6.6);
increasing to 6.4 (5.9 to 6.9) and 6.7 (6.1 to 7.2) when applying RRs of 2.5 and
3 to heavy users, respectively. Assuming a latency of 15 years, the predicted
incidence rates in 2013 were also higher compared to the observed rate. The
model did not show an increasing trend for a latency of 20 years.

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