User's Manual

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
cancers by the National Cancer Institute is expected to bear on the accuracy and repeatability of
these results.(1)
2. Researchers conducted a large battery of laboratory tests to assess the effects of exposure to
mobile phone RF on genetic material. These included tests for several kinds of abnormalities,
including mutations, chromosomal aberrations, DNA strand breaks, and structural changes in
the genetic material of blood cells called lymphocytes. None of the tests showed any effect of
the RF except for the micronucleus assay, which detects structural effects on the genetic
material. The cells in this assay showed changes after exposure to simulated cell phone
radiation, but only after 24 hours of exposure. It is possible that exposing the test cells to
radiation for this long resulted in heating. Since this assay is known to be sensitive to heating,
heat alone could have caused the abnormalities to occur. The data already in the literature on
the response of the micronucleus assay to RF are conflicting. Thus, follow-up research is
necessary.(2)
FDA is currently working with government, industry, and academic groups to ensure the
proper follow-up to these industry-funded research findings. Collaboration with the Cellular
Telecommunication Industry Association(CTIA) in particular is expected to lead to FDA
providing research recommendations and scientific oversight of new CTIA-funded research
based on such recommendations.
Two other studies of interest have been reported recently in the literature:
1. Two groups of 18 people were exposed to simulated mobile phone signals under laboratory
conditions while they performed cognitive function tests. There were no changes in the
subjects’ ability to recall words, numbers, or pictures, or in their spatial memory, but they were
able to make choices more quickly in one visual test when they were exposed to simulated
mobile phone signals. This was the only change noted among more than 20 variables
compared.(3)
2. In a study of 209 brain tumor cases and 425 matched controls, there was no increased risk of
brain tumors associated with mobile phone use. When tumors did exist in certain locations,
however, they were more likely to be on the side of the head where the mobile phone was
used. Because this occurred in only a small number of cases, the increased likelihood was
too small to be statistically significant.(4)
(1) Muscat et al. Epidemiological Study of Cellular Telephone Use and Malignant Brain Tumors.
In: States of the Science Symposium;1999 June 20; Long Beach, California.
(2) Tice et al. Tests of mobile phone signals for activity in genotoxicity and other laboratory
assays. In: Annual Meeting of the Environmental Mutagen Society; March 29, 1999,