August 1 2000

Amid mounting concerns that the Golden Age of communication may have a dark side, the US Food and Drug Administration (FDA) is turning to outside experts to help assess whether the cell phone may pose an adverse health risk through radiation.

At an August 1st workshop in Gaithersburg, MD, officials from FDA's Center for Devices and Radiologic Health (CDRH) met with scientific and technological leaders to begin to develop an approach for putting the troubling theory about cell phones to the test.

Whatever experiments ultimately show about the dangers of regular cell phone use, experts agree that the potential adverse health risks from the ubiquitous devices and other forms of wireless communications are fast becoming everyone's problem.

``(We are) moving to a situation where everyone will be exposed to radiation because of wireless communication,'' noted Dr. Gregory Lotz of the National Institute for Occupational Safety and Heath. ``We now have large populations exposed to low levels of radiofrequency (radiation).'' Cell phone use is of particular concern, Lotz stressed, because of the device's close proximity to the brain.

While it is hard to escape the current media blitz warning of the cell phone's role as a highway hazard, surprisingly little is known about the adverse effects the device may cause when its electromagnetic field penetrates the body. Thus, FDA is collaborating with industry in an attempt to fill the current knowledge gaps through a series of studies.

One factor giving rise to concerns that cell phones may carry grave health risks is the capacity of devices emitting radiofrequency radiation (RF) to heat tissue, such as brain cells, because such thermal effect is known to have genetic effects, and hence, leads to tumor growth.

Existing data on cell phone's tissue heating properties, however, is encouraging. Studies done in the last few years using animal models and tissue samples suggest that the RF emitted by cell phones, typically 800 to 1500 megaherts (MHz), is too weak to have a thermal effect on tissue.

Despite some cause for optimism, the health consequences of cell phone use over time remains a mystery.

``We don't have data on longterm exposure to RF,'' Lotz noted. While some studies on longterm cell phone use are underway, he said, ``very few'' have been completed and published.

What's more, some experts theorize that cell phones may interfere with cells' DNA mechanisms despite the devices' minimal tissue heating effect. Thus, experiments planned by FDA and industry will evaluate RF's effect on tissue at varying doses, or specific absorption rates (SAR) and varying exposure times, while keeping cell temperature as constant as possible.

A device's SAR is a reliable measure of its ability to cause cell damage and will vary according to the type of tissue through which the radiation is conducted, such as bone, muscle or fat. In the case of cell phones, SAR is highest at the ``hot spot'' where the cell phone is held to the user's ear. The Federal Communications Commission (FCC) has imposed an SAR limit of 1.6 watts per kilogram on currently-marketed cell phones.


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