Motorola StarTAC Owner's Manual page 134

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animal studies apply to the use of mobile phones. First, it is
uncertain how to apply the results obtained in rats and mice
to humans. Second, many of the studies that showed
increased tumor development used animals that had
already been treated with cancer-causing chemicals, and
other studies exposed the animals to the RF virtually
continuously—up to 22 hours per day.
For the past five years in the United States, the mobile
phone industry has supported research into the safety of
mobile phones. This research has resulted in two findings in
particular that merit additional study:
1. In a hospital-based, case-control study, researchers
looked for an association between mobile phone use
and either glioma (a type of brain cancer) or acoustic
neuroma (a benign tumor of the nerve sheath). No
statistically significant association was found between
mobile phone use and acoustic neuroma. There was
also no association between mobile phone use and
gliomas when all types of types of gliomas were
considered together. It should be noted that the
average length of mobile phone exposure in this
study was less than three years.
When 20 types of glioma were considered separately,
however, an association was found between mobile
phone use and one rare type of glioma,
neuroepithelliomatous tumors. It is possible with
multiple comparisons of the same sample that this
association occurred by chance. Moreover, the risk
did not increase with how often the mobile phone was
used, or the length of the calls. In fact, the risk
actually decreased with cumulative hours of mobile
phone use. Most cancer causing agents increase risk
with increased exposure. An ongoing study of brain