157
mode. Whereas high levels of RF can produce health effects
(by heating tissue), exposure to low level RF that does not
produce heating effects causes no known adverse health
effects.
The biological effects of radio frequency energy should not
be confused with the effects from other types of
electromagnetic energy.
Very high levels of electromagnetic energy, such as is found
in X-rays and gamma rays, can ionize biological tissues.
Ionization is a process where electrons are stripped away
from their normal locations in atoms and molecules. It can
permanently damage biological tissues including DNA, the
genetic material.
The energy levels associated with radio frequency energy,
including both radio waves and microwaves, are not great
enough to cause ionization of atoms and molecules.
Therefore, RF energy is a type of non-ionizing radiation.
Other types of non-ionizing radiation include visible light,
infrared radiation (heat), and other forms of electromagnetic
radiation with relatively low frequencies.
While RF energy does not ionize particles, large amounts can
increase body temperatures and cause tissue damage. Two
areas of the body, the eyes and the testes, are particularly
vulnerable to RF heating because there is relatively little
blood flow in them to carry away excess heat.
Research Results to Date: Is there a connection
between RF and certain health problems?
The results of most studies conducted to date say no. In
addition, attempts to replicate and confirm the few studies
that have shown a connection have failed.
The scientific community at large therefore believes that the
weight of scientific evidence does not show an association
between exposure to Radio Frequency (RF) from cell phones
and adverse health outcomes. Still the scientific community
has supported additional research to address gaps in
knowledge. Some of these studies are described below.
Interphone Study
Interphone is a large international study designed to
determine whether cell phones increase the risk of head and
neck cancer. A report published in the International Journal
of Epidemiology (June, 2010) compared cell phone usage for
more than 5,000 people with brain tumors (glioma and
meningioma) and a similar number of healthy controls.